Merge branch 'master' into android.rake-ndk-clang

45 files changed, 1253 insertions, 466 deletions

diff --git a/mrbgems/default.gembox b/mrbgems/default.gembox
index 0960ba979..64f05de10 100644
--- a/mrbgems/default.gembox
+++ b/mrbgems/default.gembox
@@ -53,7 +53,7 @@ MRuby::GemBox.new do |conf|
   # Use Enumerator class (require mruby-fiber)
   conf.gem :core => "mruby-enumerator"
 
-  # Use Enumerable::Lazy class (require mruby-enumerator)
+  # Use Enumerator::Lazy class (require mruby-enumerator)
   conf.gem :core => "mruby-enum-lazy"
 
   # Use toplevel object (main) methods extension
@@ -71,6 +71,9 @@ MRuby::GemBox.new do |conf|
   # Use Kernel module extension
   conf.gem :core => "mruby-kernel-ext"
 
+  # Use class/module extension
+  conf.gem :core => "mruby-class-ext"
+
   # Use mruby-compiler to build other mrbgems
   conf.gem :core => "mruby-compiler"
 end
diff --git a/mrbgems/mruby-array-ext/src/array.c b/mrbgems/mruby-array-ext/src/array.c
index d5c96e2cc..af947303b 100644
--- a/mrbgems/mruby-array-ext/src/array.c
+++ b/mrbgems/mruby-array-ext/src/array.c
@@ -131,7 +131,7 @@ mrb_ary_to_h(mrb_state *mrb, mrb_value ary)
 
     if (mrb_nil_p(v)) {
       mrb_raisef(mrb, E_TYPE_ERROR, "wrong element type %S at %S (expected array)",
-        mrb_str_new_cstr(mrb,  mrb_obj_classname(mrb, RARRAY_PTR(ary)[i])),
+        mrb_str_new_cstr(mrb,  mrb_obj_classname(mrb, ary_elt(ary, i))),
         mrb_fixnum_value(i)
       );
     }
diff --git a/mrbgems/mruby-array-ext/test/array.rb b/mrbgems/mruby-array-ext/test/array.rb
index ec1528fc3..09ec8d9e7 100644
--- a/mrbgems/mruby-array-ext/test/array.rb
+++ b/mrbgems/mruby-array-ext/test/array.rb
@@ -301,6 +301,17 @@ assert('Array#to_h') do
   assert_raise(ArgumentError) { [[1]].to_h }
 end
 
+assert('Array#to_h (Modified)') do
+  class A
+    def to_ary
+      $a.clear
+      nil
+    end
+  end
+  $a = [A.new]
+  assert_raise(TypeError) { $a.to_h }
+end
+
 assert("Array#index (block)") do
   assert_nil (1..10).to_a.index { |i| i % 5 == 0 and i % 7 == 0 }
   assert_equal 34, (1..100).to_a.index { |i| i % 5 == 0 and i % 7 == 0 }
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c b/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
index 218aeda90..27f27a05a 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/apibreak.c
@@ -43,7 +43,7 @@ check_lineno( mrb_irep_debug_info_file *info_file, uint16_t lineno )
 }
 
 static int32_t
-get_break_index( mrb_debug_context *dbg, int32_t bpno )
+get_break_index( mrb_debug_context *dbg, uint32_t bpno )
 {
   uint32_t i;
   int32_t index;
@@ -296,7 +296,7 @@ mrb_debug_get_break_all( mrb_state *mrb, mrb_debug_context *dbg, uint32_t size,
 int32_t
 mrb_debug_get_break( mrb_state *mrb, mrb_debug_context *dbg, uint32_t bpno, mrb_debug_breakpoint *bp )
 {
-  uint32_t index;
+  int32_t index;
 
   if((mrb == NULL) || (dbg == NULL) || (bp == NULL)) {
     return MRB_DEBUG_INVALID_ARGUMENT;
diff --git a/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c b/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
index 1c77d1ef8..33e9575bf 100644
--- a/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
+++ b/mrbgems/mruby-bin-debugger/tools/mrdb/apilist.c
@@ -71,7 +71,7 @@ dirname(mrb_state *mrb, const char *path)
   }
 
   p = strrchr(path, '/');
-  len = p != NULL ? p - path : strlen(path);
+  len = p != NULL ? (size_t)(p - path) : strlen(path);
 
   dir = mrb_malloc(mrb, len + 1);
   strncpy(dir, path, len);
diff --git a/mrbgems/mruby-bin-mruby/bintest/mruby.rb b/mrbgems/mruby-bin-mruby/bintest/mruby.rb
index 01fc94632..72ac6586d 100644
--- a/mrbgems/mruby-bin-mruby/bintest/mruby.rb
+++ b/mrbgems/mruby-bin-mruby/bintest/mruby.rb
@@ -44,3 +44,17 @@ EOS
   script.flush
   assert_equal "\"test\"\n\"fin\"\n", `#{cmd('mruby')} #{script.path}`
 end
+
+assert('garbage collecting built-in classes') do
+  script = Tempfile.new('test.rb')
+
+  script.write <<RUBY
+NilClass = nil
+GC.start
+Array.dup
+print nil.class.to_s
+RUBY
+  script.flush
+  assert_equal "NilClass", `#{cmd('mruby')} #{script.path}`
+  assert_equal 0, $?.exitstatus
+end
diff --git a/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c b/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
index ab6c6688f..d10535140 100644
--- a/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
+++ b/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c
@@ -6,6 +6,7 @@
 #include <mruby/compile.h>
 #include <mruby/dump.h>
 #include <mruby/variable.h>
+#include <mruby/throw.h>
 
 #ifdef MRB_DISABLE_STDIO
 static void
@@ -176,6 +177,8 @@ main(int argc, char **argv)
   mrbc_context *c;
   mrb_value v;
   mrb_sym zero_sym;
+  struct mrb_jmpbuf c_jmp;
+  int ai;
 
   if (mrb == NULL) {
     fputs("Invalid mrb_state, exiting mruby\n", stderr);
@@ -189,59 +192,67 @@ main(int argc, char **argv)
     return n;
   }
 
-  ARGV = mrb_ary_new_capa(mrb, args.argc);
-  for (i = 0; i < args.argc; i++) {
-    char* utf8 = mrb_utf8_from_locale(args.argv[i], -1);
-    if (utf8) {
-      mrb_ary_push(mrb, ARGV, mrb_str_new_cstr(mrb, utf8));
-      mrb_utf8_free(utf8);
+  ai = mrb_gc_arena_save(mrb);
+  MRB_TRY(&c_jmp) {
+    mrb->jmp = &c_jmp;
+    ARGV = mrb_ary_new_capa(mrb, args.argc);
+    for (i = 0; i < args.argc; i++) {
+      char* utf8 = mrb_utf8_from_locale(args.argv[i], -1);
+      if (utf8) {
+        mrb_ary_push(mrb, ARGV, mrb_str_new_cstr(mrb, utf8));
+        mrb_utf8_free(utf8);
+      }
     }
-  }
-  mrb_define_global_const(mrb, "ARGV", ARGV);
-
-  c = mrbc_context_new(mrb);
-  if (args.verbose)
-    c->dump_result = TRUE;
-  if (args.check_syntax)
-    c->no_exec = TRUE;
-
-  /* Set $0 */
-  zero_sym = mrb_intern_lit(mrb, "$0");
-  if (args.rfp) {
-    const char *cmdline;
-    cmdline = args.cmdline ? args.cmdline : "-";
-    mrbc_filename(mrb, c, cmdline);
-    mrb_gv_set(mrb, zero_sym, mrb_str_new_cstr(mrb, cmdline));
-  }
-  else {
-    mrbc_filename(mrb, c, "-e");
-    mrb_gv_set(mrb, zero_sym, mrb_str_new_lit(mrb, "-e"));
-  }
+    mrb_define_global_const(mrb, "ARGV", ARGV);
 
-  /* Load program */
-  if (args.mrbfile) {
-    v = mrb_load_irep_file_cxt(mrb, args.rfp, c);
-  }
-  else if (args.rfp) {
-    v = mrb_load_file_cxt(mrb, args.rfp, c);
-  }
-  else {
-    char* utf8 = mrb_utf8_from_locale(args.cmdline, -1);
-    if (!utf8) abort();
-    v = mrb_load_string_cxt(mrb, utf8, c);
-    mrb_utf8_free(utf8);
-  }
+    c = mrbc_context_new(mrb);
+    if (args.verbose)
+      c->dump_result = TRUE;
+    if (args.check_syntax)
+      c->no_exec = TRUE;
+
+    /* Set $0 */
+    zero_sym = mrb_intern_lit(mrb, "$0");
+    if (args.rfp) {
+      const char *cmdline;
+      cmdline = args.cmdline ? args.cmdline : "-";
+      mrbc_filename(mrb, c, cmdline);
+      mrb_gv_set(mrb, zero_sym, mrb_str_new_cstr(mrb, cmdline));
+    }
+    else {
+      mrbc_filename(mrb, c, "-e");
+      mrb_gv_set(mrb, zero_sym, mrb_str_new_lit(mrb, "-e"));
+    }
+
+    /* Load program */
+    if (args.mrbfile) {
+      v = mrb_load_irep_file_cxt(mrb, args.rfp, c);
+    }
+    else if (args.rfp) {
+      v = mrb_load_file_cxt(mrb, args.rfp, c);
+    }
+    else {
+      char* utf8 = mrb_utf8_from_locale(args.cmdline, -1);
+      if (!utf8) abort();
+      v = mrb_load_string_cxt(mrb, utf8, c);
+      mrb_utf8_free(utf8);
+    }
 
-  mrbc_context_free(mrb, c);
-  if (mrb->exc) {
-    if (!mrb_undef_p(v)) {
-      mrb_print_error(mrb);
+    mrb_gc_arena_restore(mrb, ai);
+    mrbc_context_free(mrb, c);
+    if (mrb->exc) {
+      if (!mrb_undef_p(v)) {
+        mrb_print_error(mrb);
+      }
+      n = -1;
+    }
+    else if (args.check_syntax) {
+      printf("Syntax OK\n");
     }
-    n = -1;
   }
-  else if (args.check_syntax) {
-    printf("Syntax OK\n");
+  MRB_CATCH(&c_jmp) {           /* error */
   }
+  MRB_END_EXC(&c_jmp);
   cleanup(mrb, &args);
 
   return n == 0 ? EXIT_SUCCESS : EXIT_FAILURE;
diff --git a/mrbgems/mruby-class-ext/mrbgem.rake b/mrbgems/mruby-class-ext/mrbgem.rake
new file mode 100644
index 000000000..a384b1eef
--- /dev/null
+++ b/mrbgems/mruby-class-ext/mrbgem.rake
@@ -0,0 +1,5 @@
+MRuby::Gem::Specification.new('mruby-class-ext') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'class/module extension'
+end
diff --git a/mrbgems/mruby-class-ext/src/class.c b/mrbgems/mruby-class-ext/src/class.c
new file mode 100644
index 000000000..8ca7d66c2
--- /dev/null
+++ b/mrbgems/mruby-class-ext/src/class.c
@@ -0,0 +1,23 @@
+#include "mruby.h"
+#include "mruby/class.h"
+#include "mruby/string.h"
+
+static mrb_value
+mrb_mod_name(mrb_state *mrb, mrb_value self)
+{
+  mrb_value name = mrb_class_path(mrb, mrb_class_ptr(self));
+  return mrb_nil_p(name)? name : mrb_str_dup(mrb, name);
+}
+
+void
+mrb_mruby_class_ext_gem_init(mrb_state *mrb)
+{
+  struct RClass *mod = mrb->module_class;
+
+  mrb_define_method(mrb, mod, "name", mrb_mod_name, MRB_ARGS_NONE());
+}
+
+void
+mrb_mruby_class_ext_gem_final(mrb_state *mrb)
+{
+}
diff --git a/mrbgems/mruby-class-ext/test/module.rb b/mrbgems/mruby-class-ext/test/module.rb
new file mode 100644
index 000000000..f721ad0c6
--- /dev/null
+++ b/mrbgems/mruby-class-ext/test/module.rb
@@ -0,0 +1,10 @@
+assert 'Module#name' do
+  module A
+    class B
+    end
+  end
+
+  assert_nil A::B.singleton_class.name
+  assert_equal 'Fixnum', Fixnum.name
+  assert_equal 'A::B', A::B.name
+end
diff --git a/mrbgems/mruby-compiler/bintest/mrbc.rb b/mrbgems/mruby-compiler/bintest/mrbc.rb
index e4dc6a9a8..e27365edb 100644
--- a/mrbgems/mruby-compiler/bintest/mrbc.rb
+++ b/mrbgems/mruby-compiler/bintest/mrbc.rb
@@ -10,3 +10,12 @@ assert('Compiling multiple files without new line in last line. #2361') do
   assert_equal "#{cmd('mrbc')}:#{a.path}:Syntax OK", result.chomp
   assert_equal 0, $?.exitstatus
 end
+
+assert('parsing function with void argument') do
+  a, out = Tempfile.new('a.rb'), Tempfile.new('out.mrb')
+  a.write('f ()')
+  a.flush
+  result = `#{cmd('mrbc')} -c -o #{out.path} #{a.path} 2>&1`
+  assert_equal "#{cmd('mrbc')}:#{a.path}:Syntax OK", result.chomp
+  assert_equal 0, $?.exitstatus
+end
diff --git a/mrbgems/mruby-compiler/core/codegen.c b/mrbgems/mruby-compiler/core/codegen.c
index 9b064b867..23e036d49 100644
--- a/mrbgems/mruby-compiler/core/codegen.c
+++ b/mrbgems/mruby-compiler/core/codegen.c
@@ -93,6 +93,7 @@ codegen_error(codegen_scope *s, const char *message)
   if (!s) return;
   while (s->prev) {
     codegen_scope *tmp = s->prev;
+    mrb_free(s->mrb, s->iseq);
     mrb_pool_close(s->mpool);
     s = tmp;
   }
@@ -387,6 +388,9 @@ dispatch(codegen_scope *s, int pc)
     scope_error(s);
     break;
   }
+  if (diff > MAXARG_sBx) {
+    codegen_error(s, "too distant jump address");
+  }
   s->iseq[pc] = MKOP_AsBx(c, GETARG_A(i), diff);
 }
 
@@ -500,7 +504,12 @@ new_lit(codegen_scope *s, mrb_value val)
   return i;
 }
 
-static inline int
+/* method symbols should be fit in 9 bits */
+#define MAXMSYMLEN 512
+/* maximum symbol numbers */
+#define MAXSYMLEN 65536
+
+static int
 new_msym(codegen_scope *s, mrb_sym sym)
 {
   size_t i, len;
@@ -508,20 +517,20 @@ new_msym(codegen_scope *s, mrb_sym sym)
   mrb_assert(s->irep);
 
   len = s->irep->slen;
-  if (len > 256) len = 256;
+  if (len > MAXMSYMLEN) len = MAXMSYMLEN;
   for (i=0; i<len; i++) {
     if (s->irep->syms[i] == sym) return i;
     if (s->irep->syms[i] == 0) break;
   }
-  if (i == 256) {
-    codegen_error(s, "too many symbols (max 256)");
+  if (i == MAXMSYMLEN) {
+    codegen_error(s, "too many symbols (max " MRB_STRINGIZE(MAXMSYMLEN) ")");
   }
   s->irep->syms[i] = sym;
   if (i == s->irep->slen) s->irep->slen++;
   return i;
 }
 
-static inline int
+static int
 new_sym(codegen_scope *s, mrb_sym sym)
 {
   size_t i;
@@ -529,13 +538,18 @@ new_sym(codegen_scope *s, mrb_sym sym)
   for (i=0; i<s->irep->slen; i++) {
     if (s->irep->syms[i] == sym) return i;
   }
-  if (s->irep->slen > 125 && s->irep->slen < 256) {
-    s->irep->syms = (mrb_sym *)codegen_realloc(s, s->irep->syms, sizeof(mrb_sym)*65536);
-    for (i = 0; i < 256 - s->irep->slen; i++) {
+  if (s->irep->slen == MAXSYMLEN) {
+    codegen_error(s, "too many symbols (max " MRB_STRINGIZE(MAXSYMLEN) ")");
+  }
+
+  if (s->irep->slen > MAXMSYMLEN/2 && s->scapa == MAXMSYMLEN) {
+    s->scapa = MAXSYMLEN;
+    s->irep->syms = (mrb_sym *)codegen_realloc(s, s->irep->syms, sizeof(mrb_sym)*MAXSYMLEN);
+    for (i = s->irep->slen; i < MAXMSYMLEN; i++) {
       static const mrb_sym mrb_sym_zero = { 0 };
-      s->irep->syms[i + s->irep->slen] = mrb_sym_zero;
+      s->irep->syms[i] = mrb_sym_zero;
     }
-    s->irep->slen = 256;
+    s->irep->slen = MAXMSYMLEN;
   }
   s->irep->syms[s->irep->slen] = sym;
   return s->irep->slen++;
@@ -588,9 +602,6 @@ for_body(codegen_scope *s, node *tree)
 
   push();                       /* push for a block parameter */
 
-  lp = loop_push(s, LOOP_FOR);
-  lp->pc1 = new_label(s);
-
   /* generate loop variable */
   n2 = tree->car;
   genop(s, MKOP_Ax(OP_ENTER, 0x40000));
@@ -600,6 +611,11 @@ for_body(codegen_scope *s, node *tree)
   else {
     gen_vmassignment(s, n2, 1, VAL);
   }
+  /* construct loop */
+  lp = loop_push(s, LOOP_FOR);
+  lp->pc2 = new_label(s);
+
+  /* loop body */
   codegen(s, tree->cdr->cdr->car, VAL);
   pop();
   if (s->pc > 0) {
@@ -650,6 +666,9 @@ lambda_body(codegen_scope *s, node *tree, int blk)
     ka = kd = 0;
     ba = tree->car->cdr->cdr->cdr->cdr ? 1 : 0;
 
+    if (ma > 0x1f || oa > 0x1f || pa > 0x1f || ka > 0x1f) {
+      codegen_error(s, "too many formal arguments");
+    }
     a = ((mrb_aspec)(ma & 0x1f) << 18)
       | ((mrb_aspec)(oa & 0x1f) << 13)
       | ((ra & 1) << 12)
@@ -770,6 +789,8 @@ attrsym(codegen_scope *s, mrb_sym a)
   return mrb_intern(s->mrb, name2, len+1);
 }
 
+#define CALL_MAXARGS 127
+
 static int
 gen_values(codegen_scope *s, node *t, int val)
 {
@@ -778,7 +799,9 @@ gen_values(codegen_scope *s, node *t, int val)
 
   while (t) {
     is_splat = (intptr_t)t->car->car == NODE_SPLAT; /* splat mode */
-    if (n >= 127 || is_splat) {
+    if (
+      n >= CALL_MAXARGS - 1 /* need to subtract one because vm.c expects an array if n == CALL_MAXARGS */
+      || is_splat) {
       if (val) {
         if (is_splat && n == 0 && (intptr_t)t->car->cdr->car == NODE_ARRAY) {
           codegen(s, t->car->cdr, VAL);
@@ -812,8 +835,6 @@ gen_values(codegen_scope *s, node *t, int val)
         }
       }
       else {
-        codegen(s, t->car->cdr, NOVAL);
-        t = t->cdr;
         while (t) {
           codegen(s, t->car, NOVAL);
           t = t->cdr;
@@ -829,8 +850,6 @@ gen_values(codegen_scope *s, node *t, int val)
   return n;
 }
 
-#define CALL_MAXARGS 127
-
 static void
 gen_call(codegen_scope *s, node *tree, mrb_sym name, int sp, int val, int safe)
 {
@@ -1057,7 +1076,9 @@ gen_vmassignment(codegen_scope *s, node *tree, int rhs, int val)
         n++;
       }
     }
-    push();
+    if (!val) {
+      push();
+    }
   }
 }
 
@@ -1360,6 +1381,10 @@ codegen(codegen_scope *s, node *tree, int val)
       int pos1, pos2;
       node *e = tree->cdr->cdr->car;
 
+      if (!tree->car) {
+        codegen(s, e, val);
+        return;
+      }
       switch ((intptr_t)tree->car->car) {
       case NODE_TRUE:
       case NODE_INT:
@@ -1510,7 +1535,9 @@ codegen(codegen_scope *s, node *tree, int val)
         genop(s, MKOP_A(OP_LOADNIL, cursp()));
         if (pos3) dispatch_linked(s, pos3);
         if (head) pop();
-        genop(s, MKOP_AB(OP_MOVE, cursp(), pos));
+        if (cursp() != pos) {
+          genop(s, MKOP_AB(OP_MOVE, cursp(), pos));
+        }
         push();
       }
       else {
@@ -1655,7 +1682,6 @@ codegen(codegen_scope *s, node *tree, int val)
         }
         tree = tree->car;
         if (tree->car) {                /* pre */
-          int first = TRUE;
           t = tree->car;
           n = 0;
           while (t) {
@@ -1664,10 +1690,7 @@ codegen(codegen_scope *s, node *tree, int val)
               n++;
             }
             else {
-              if (first) {
-                genop(s, MKOP_A(OP_LOADNIL, rhs+n));
-                first = FALSE;
-              }
+              genop(s, MKOP_A(OP_LOADNIL, rhs+n));
               gen_assignment(s, t->car, rhs+n, NOVAL);
             }
             t = t->cdr;
@@ -1746,6 +1769,7 @@ codegen(codegen_scope *s, node *tree, int val)
         genop(s, MKOP_A(OP_RESCUE, exc));
         genop(s, MKOP_A(OP_LOADF, exc));
         dispatch(s, noexc);
+        loop_pop(s, NOVAL);
       }
       else if ((intptr_t)tree->car->car == NODE_CALL) {
         node *n = tree->car->cdr;
@@ -1795,8 +1819,10 @@ codegen(codegen_scope *s, node *tree, int val)
         int pos;
 
         pop();
-        if (val && vsp >= 0) {
-          genop(s, MKOP_AB(OP_MOVE, vsp, cursp()));
+        if (val) {
+          if (vsp >= 0) {
+            genop(s, MKOP_AB(OP_MOVE, vsp, cursp()));
+          }
           pos = genop(s, MKOP_AsBx(name[0]=='|'?OP_JMPIF:OP_JMPNOT, cursp(), 0));
         }
         else {
@@ -2012,7 +2038,7 @@ codegen(codegen_scope *s, node *tree, int val)
     break;
 
   case NODE_REDO:
-    if (!s->loop) {
+    if (!s->loop || s->loop->type == LOOP_BEGIN || s->loop->type == LOOP_RESCUE) {
       raise_error(s, "unexpected redo");
     }
     else {
@@ -2021,6 +2047,7 @@ codegen(codegen_scope *s, node *tree, int val)
       }
       genop(s, MKOP_sBx(OP_JMP, s->loop->pc2 - s->pc));
     }
+    if (val) push();
     break;
 
   case NODE_RETRY:
@@ -2055,6 +2082,7 @@ codegen(codegen_scope *s, node *tree, int val)
           genop(s, MKOP_sBx(OP_JMP, lp->pc1 - s->pc));
         }
       }
+      if (val) push();
     }
     break;
 
@@ -2194,7 +2222,7 @@ codegen(codegen_scope *s, node *tree, int val)
   case NODE_FLOAT:
     if (val) {
       char *p = (char*)tree;
-      mrb_float f = str_to_mrb_float(p);
+      mrb_float f = mrb_float_read(p, NULL);
       int off = new_lit(s, mrb_float_value(s->mrb, f));
 
       genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
@@ -2208,9 +2236,9 @@ codegen(codegen_scope *s, node *tree, int val)
       tree = tree->cdr;
       switch (nt) {
       case NODE_FLOAT:
-        {
+        if (val) {
           char *p = (char*)tree;
-          mrb_float f = str_to_mrb_float(p);
+          mrb_float f = mrb_float_read(p, NULL);
           int off = new_lit(s, mrb_float_value(s->mrb, -f));
 
           genop(s, MKOP_ABx(OP_LOADL, cursp(), off));
@@ -2219,7 +2247,7 @@ codegen(codegen_scope *s, node *tree, int val)
         break;
 
       case NODE_INT:
-        {
+        if (val) {
           char *p = (char*)tree->car;
           int base = (intptr_t)tree->cdr->car;
           mrb_int i;
@@ -2248,7 +2276,7 @@ codegen(codegen_scope *s, node *tree, int val)
         break;
 
       default:
-        {
+        if (val) {
           int sym = new_msym(s, mrb_intern_lit(s->mrb, "-"));
 
           genop(s, MKOP_ABx(OP_LOADI, cursp(), 0));
@@ -2257,6 +2285,9 @@ codegen(codegen_scope *s, node *tree, int val)
           pop(); pop();
           genop(s, MKOP_ABC(OP_SUB, cursp(), sym, 2));
         }
+        else {
+          codegen(s, tree, NOVAL);
+        }
         break;
       }
     }
@@ -2282,7 +2313,11 @@ codegen(codegen_scope *s, node *tree, int val)
     if (val) {
       node *n = tree;
 
-      if (!n) break;
+      if (!n) {
+        genop(s, MKOP_A(OP_LOADNIL, cursp()));
+        push();
+        break;
+      }
       codegen(s, n->car, VAL);
       n = n->cdr;
       while (n) {
@@ -2539,13 +2574,31 @@ codegen(codegen_scope *s, node *tree, int val)
       genop(s, MKOP_A(OP_TCLASS, cursp()));
       push();
       while (t) {
-        int symbol = new_msym(s, sym(t->car));
+        int symbol;
+        if (num >= CALL_MAXARGS - 1) {
+          pop_n(num);
+          genop(s, MKOP_ABC(OP_ARRAY, cursp(), cursp(), num));
+          while (t) {
+            symbol = new_msym(s, sym(t->car));
+            push();
+            genop(s, MKOP_ABx(OP_LOADSYM, cursp(), symbol));
+            pop();
+            genop(s, MKOP_AB(OP_ARYPUSH, cursp(), cursp()+1));
+            t = t->cdr;
+          }
+          num = CALL_MAXARGS;
+          break;
+        }
+        symbol = new_msym(s, sym(t->car));
         genop(s, MKOP_ABx(OP_LOADSYM, cursp(), symbol));
         push();
         t = t->cdr;
         num++;
       }
-      pop_n(num + 1);
+      pop();
+      if (num < CALL_MAXARGS) {
+        pop_n(num);
+      }
       genop(s, MKOP_ABC(OP_SEND, cursp(), undef, num));
       if (val) {
         push();
@@ -2713,13 +2766,13 @@ scope_new(mrb_state *mrb, codegen_scope *prev, node *lv)
 
   p->icapa = 1024;
   p->iseq = (mrb_code*)mrb_malloc(mrb, sizeof(mrb_code)*p->icapa);
-  p->irep->iseq = p->iseq;
+  p->irep->iseq = NULL;
 
   p->pcapa = 32;
   p->irep->pool = (mrb_value*)mrb_malloc(mrb, sizeof(mrb_value)*p->pcapa);
   p->irep->plen = 0;
 
-  p->scapa = 256;
+  p->scapa = MAXMSYMLEN;
   p->irep->syms = (mrb_sym*)mrb_malloc(mrb, sizeof(mrb_sym)*p->scapa);
   p->irep->slen = 0;
 
@@ -2797,6 +2850,7 @@ scope_finish(codegen_scope *s)
     memcpy(fname, s->filename, fname_len);
     fname[fname_len] = '\0';
     irep->filename = fname;
+    irep->own_filename = TRUE;
   }
 
   irep->nlocals = s->nlocals;
@@ -2904,9 +2958,6 @@ mrb_generate_code(mrb_state *mrb, parser_state *p)
     return proc;
   }
   MRB_CATCH(&scope->jmp) {
-    if (scope->filename == scope->irep->filename) {
-      scope->irep->filename = NULL;
-    }
     mrb_irep_decref(mrb, scope->irep);
     mrb_pool_close(scope->mpool);
     return NULL;
diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index 426c262fb..f8e4eb72f 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -41,6 +41,7 @@ static void yyerror(parser_state *p, const char *s);
 static void yywarn(parser_state *p, const char *s);
 static void yywarning(parser_state *p, const char *s);
 static void backref_error(parser_state *p, node *n);
+static void void_expr_error(parser_state *p, node *n);
 static void tokadd(parser_state *p, int32_t c);
 
 #define identchar(c) (ISALNUM(c) || (c) == '_' || !ISASCII(c))
@@ -870,6 +871,7 @@ call_with_block(parser_state *p, node *a, node *b)
     break;
   case NODE_CALL:
   case NODE_FCALL:
+  case NODE_SCALL:
     n = a->cdr->cdr->cdr;
     if (!n->car) n->car = cons(0, b);
     else {
@@ -1097,7 +1099,7 @@ heredoc_end(parser_state *p)
 %type <nd> literal numeric cpath symbol
 %type <nd> top_compstmt top_stmts top_stmt
 %type <nd> bodystmt compstmt stmts stmt expr arg primary command command_call method_call
-%type <nd> expr_value arg_value arg_rhs primary_value
+%type <nd> expr_value arg_rhs primary_value
 %type <nd> if_tail opt_else case_body cases opt_rescue exc_list exc_var opt_ensure
 %type <nd> args call_args opt_call_args
 %type <nd> paren_args opt_paren_args variable
@@ -1322,7 +1324,7 @@ stmt            : keyword_alias fsym {p->lstate = EXPR_FNAME;} fsym
                     {
                       $$ = new_asgn(p, $1, new_array(p, $3));
                     }
-                | mlhs '=' arg_value
+                | mlhs '=' arg
                     {
                       $$ = new_masgn(p, $1, $3);
                     }
@@ -1401,7 +1403,10 @@ expr            : command_call
 expr_value      : expr
                     {
                       if (!$1) $$ = new_nil(p);
-                      else $$ = $1;
+                      else {
+                        void_expr_error(p, $1);
+                        $$ = $1;
+                      }
                     }
                 ;
 
@@ -1907,20 +1912,13 @@ arg             : lhs '=' arg_rhs
                     }
                 ;
 
-arg_value       : arg
-                    {
-                      $$ = $1;
-                      if (!$$) $$ = new_nil(p);
-                    }
-                ;
-
 aref_args       : none
                 | args trailer
                     {
                       $$ = $1;
                       NODE_LINENO($$, $1);
                     }
-                | args ',' assocs trailer
+                | args comma assocs trailer
                     {
                       $$ = push($1, new_hash(p, $3));
                     }
@@ -1931,9 +1929,14 @@ aref_args       : none
                     }
                 ;
 
-arg_rhs         : arg   %prec tOP_ASGN
+arg_rhs         : arg %prec tOP_ASGN
+                    {
+                      void_expr_error(p, $1);
+                      $$ = $1;
+                    }
                 | arg modifier_rescue arg
                     {
+                      void_expr_error(p, $1);
                       $$ = new_mod_rescue(p, $1, $3);
                     }
                 ;
@@ -1955,7 +1958,7 @@ opt_call_args   : none
                       $$ = cons($1,0);
                       NODE_LINENO($$, $1);
                     }
-                | args ',' assocs ','
+                | args comma assocs ','
                     {
                       $$ = cons(push($1, new_hash(p, $3)), 0);
                       NODE_LINENO($$, $1);
@@ -1982,7 +1985,7 @@ call_args       : command
                       $$ = cons(list1(new_hash(p, $1)), $2);
                       NODE_LINENO($$, $1);
                     }
-                | args ',' assocs opt_block_arg
+                | args comma assocs opt_block_arg
                     {
                       $$ = cons(push($1, new_hash(p, $3)), $4);
                       NODE_LINENO($$, $1);
@@ -2005,13 +2008,13 @@ command_args    :  {
                     }
                 ;
 
-block_arg       : tAMPER arg_value
+block_arg       : tAMPER arg
                     {
                       $$ = new_block_arg(p, $2);
                     }
                 ;
 
-opt_block_arg   : ',' block_arg
+opt_block_arg   : comma block_arg
                     {
                       $$ = $2;
                     }
@@ -2021,44 +2024,47 @@ opt_block_arg   : ',' block_arg
                     }
                 ;
 
-args            : arg_value
+comma           : ','
+                | ','  heredoc_bodies
+                ;
+
+args            : arg
                     {
+                      void_expr_error(p, $1);
                       $$ = cons($1, 0);
                       NODE_LINENO($$, $1);
                     }
-                | tSTAR arg_value
+                | tSTAR arg
                     {
+                      void_expr_error(p, $2);
                       $$ = cons(new_splat(p, $2), 0);
                       NODE_LINENO($$, $2);
                     }
-                | args ',' arg_value
+                | args comma arg
                     {
+                      void_expr_error(p, $3);
                       $$ = push($1, $3);
                     }
-                | args ',' tSTAR arg_value
+                | args comma tSTAR arg
                     {
+                      void_expr_error(p, $4);
                       $$ = push($1, new_splat(p, $4));
                     }
-                | args ',' heredoc_bodies arg_value
-                    {
-                      $$ = push($1, $4);
-                    }
-                | args ',' heredoc_bodies tSTAR arg_value
-                    {
-                      $$ = push($1, new_splat(p, $5));
-                    }
                 ;
 
-mrhs            : args ',' arg_value
+mrhs            : args comma arg
                     {
+                      void_expr_error(p, $3);
                       $$ = push($1, $3);
                     }
-                | args ',' tSTAR arg_value
+                | args comma tSTAR arg
                     {
+                      void_expr_error(p, $4);
                       $$ = push($1, new_splat(p, $4));
                     }
-                | tSTAR arg_value
+                | tSTAR arg
                     {
+                      void_expr_error(p, $2);
                       $$ = list1(new_splat(p, $2));
                     }
                 ;
@@ -2097,7 +2103,7 @@ primary         : literal
                     }
                 | tLPAREN_ARG {p->lstate = EXPR_ENDARG;} rparen
                     {
-                      $$ = 0;
+                      $$ = new_nil(p);
                     }
                 | tLPAREN compstmt ')'
                     {
@@ -2125,17 +2131,9 @@ primary         : literal
                     {
                       $$ = new_return(p, 0);
                     }
-                | keyword_yield '(' call_args rparen
+                | keyword_yield opt_paren_args
                     {
-                      $$ = new_yield(p, $3);
-                    }
-                | keyword_yield '(' rparen
-                    {
-                      $$ = new_yield(p, 0);
-                    }
-                | keyword_yield
-                    {
-                      $$ = new_yield(p, 0);
+                      $$ = new_yield(p, $2);
                     }
                 | keyword_not '(' expr rparen
                     {
@@ -2450,7 +2448,7 @@ block_param     : f_arg ',' f_block_optarg ',' f_rest_arg opt_f_block_arg
                     }
                 | f_arg ','
                     {
-                      $$ = new_args(p, $1, 0, 1, 0, 0);
+                      $$ = new_args(p, $1, 0, 0, 0, 0);
                     }
                 | f_arg ',' f_rest_arg ',' f_arg opt_f_block_arg
                     {
@@ -2688,7 +2686,7 @@ opt_rescue      : keyword_rescue exc_list exc_var then
                 | none
                 ;
 
-exc_list        : arg_value
+exc_list        : arg
                     {
                         $$ = list1($1);
                     }
@@ -2783,10 +2781,6 @@ regexp          : tREGEXP_BEG tREGEXP
 heredoc         : tHEREDOC_BEG
                 ;
 
-opt_heredoc_bodies : /* none */
-                   | heredoc_bodies
-                   ;
-
 heredoc_bodies  : heredoc_body
                 | heredoc_bodies heredoc_body
                 ;
@@ -3115,7 +3109,7 @@ f_opt_asgn      : tIDENTIFIER '='
                     }
                 ;
 
-f_opt           : f_opt_asgn arg_value
+f_opt           : f_opt_asgn arg
                     {
                       $$ = cons(nsym($1), $2);
                     }
@@ -3233,23 +3227,23 @@ assocs          : assoc
                     }
                 ;
 
-assoc           : arg_value tASSOC arg_value
+assoc           : arg tASSOC arg
                     {
                       $$ = cons($1, $3);
                     }
-                | tLABEL arg_value
+                | tLABEL arg
                     {
                       $$ = cons(new_sym(p, $1), $2);
                     }
-                | tLABEL_END arg_value
+                | tLABEL_END arg
                     {
                       $$ = cons(new_sym(p, new_strsym(p, $1)), $2);
                     }
-                | tSTRING_BEG tLABEL_END arg_value
+                | tSTRING_BEG tLABEL_END arg
                     {
                       $$ = cons(new_sym(p, new_strsym(p, $2)), $3);
                     }
-                | tSTRING_BEG string_rep tLABEL_END arg_value
+                | tSTRING_BEG string_rep tLABEL_END arg
                     {
                       $$ = cons(new_dsym(p, push($2, $3)), $4);
                     }
@@ -3308,11 +3302,12 @@ rbracket        : opt_nl ']'
 
 trailer         : /* none */
                 | nl
-                | ','
+                | comma
                 ;
 
 term            : ';' {yyerrok;}
                 | nl
+                | heredoc_body
                 ;
 
 nl              : '\n'
@@ -3320,10 +3315,10 @@ nl              : '\n'
                       p->lineno++;
                       p->column = 0;
                     }
-                  opt_heredoc_bodies
+                ;
 
 terms           : term
-                | terms ';' {yyerrok;}
+                | terms term
                 ;
 
 none            : /* none */
@@ -3430,6 +3425,26 @@ backref_error(parser_state *p, node *n)
   }
 }
 
+static void
+void_expr_error(parser_state *p, node *n)
+{
+  int c;
+
+  if (n == NULL) return;
+  c = (int)(intptr_t)n->car;
+  switch (c) {
+  case NODE_BREAK:
+  case NODE_RETURN:
+  case NODE_NEXT:
+  case NODE_REDO:
+  case NODE_RETRY:
+    yyerror(p, "void value expression");
+    break;
+  default:
+    break;
+  }
+}
+
 static void pushback(parser_state *p, int c);
 static mrb_bool peeks(parser_state *p, const char *s);
 static mrb_bool skips(parser_state *p, const char *s);
@@ -3730,6 +3745,44 @@ scan_hex(const int *start, int len, int *retlen)
   return retval;
 }
 
+static int32_t
+read_escape_unicode(parser_state *p, int limit)
+{
+  int32_t c;
+  int buf[9];
+  int i;
+
+  /* Look for opening brace */
+  i = 0;
+  buf[0] = nextc(p);
+  if (buf[0] < 0) goto eof;
+  if (ISXDIGIT(buf[0])) {
+    /* \uxxxx form */
+    for (i=1; i<limit; i++) {
+      buf[i] = nextc(p);
+      if (buf[i] < 0) goto eof;
+      if (!ISXDIGIT(buf[i])) {
+        pushback(p, buf[i]);
+        break;
+      }
+    }
+  }
+  else {
+    pushback(p, buf[0]);
+  }
+  c = scan_hex(buf, i, &i);
+  if (i == 0) {
+  eof:
+    yyerror(p, "Invalid escape character syntax");
+    return -1;
+  }
+  if (c < 0 || c > 0x10FFFF || (c & 0xFFFFF800) == 0xD800) {
+    yyerror(p, "Invalid Unicode code point");
+    return -1;
+  }
+  return c;
+}
+
 /* Return negative to indicate Unicode code point */
 static int32_t
 read_escape(parser_state *p)
@@ -3802,53 +3855,17 @@ read_escape(parser_state *p)
   return c;
 
   case 'u':     /* Unicode */
-  {
-    int buf[9];
-    int i;
-
-    /* Look for opening brace */
-    i = 0;
-    buf[0] = nextc(p);
-    if (buf[0] < 0) goto eof;
-    if (buf[0] == '{') {
+    if (peek(p, '{')) {
       /* \u{xxxxxxxx} form */
-      for (i=0; i<9; i++) {
-        buf[i] = nextc(p);
-        if (buf[i] < 0) goto eof;
-        if (buf[i] == '}') {
-          break;
-        }
-        else if (!ISXDIGIT(buf[i])) {
-          yyerror(p, "Invalid escape character syntax");
-          pushback(p, buf[i]);
-          return 0;
-        }
-      }
-    }
-    else if (ISXDIGIT(buf[0])) {
-      /* \uxxxx form */
-      for (i=1; i<4; i++) {
-        buf[i] = nextc(p);
-        if (buf[i] < 0) goto eof;
-        if (!ISXDIGIT(buf[i])) {
-          pushback(p, buf[i]);
-          break;
-        }
-      }
+      nextc(p);
+      c = read_escape_unicode(p, 8);
+      if (c < 0) return 0;
+      if (nextc(p) != '}') goto eof;
     }
     else {
-      pushback(p, buf[0]);
+      c = read_escape_unicode(p, 4);
+      if (c < 0) return 0;
     }
-    c = scan_hex(buf, i, &i);
-    if (i == 0) {
-      yyerror(p, "Invalid escape character syntax");
-      return 0;
-    }
-    if (c < 0 || c > 0x10FFFF || (c & 0xFFFFF800) == 0xD800) {
-      yyerror(p, "Invalid Unicode code point");
-      return 0;
-    }
-  }
   return -c;
 
   case 'b':/* backspace */
@@ -3906,7 +3923,10 @@ parse_string(parser_state *p)
   int beg = (intptr_t)p->lex_strterm->cdr->cdr->car;
   int end = (intptr_t)p->lex_strterm->cdr->cdr->cdr;
   parser_heredoc_info *hinf = (type & STR_FUNC_HEREDOC) ? parsing_heredoc_inf(p) : NULL;
+  int cmd_state = p->cmd_start;
 
+  if (beg == 0) beg = -3;       /* should never happen */
+  if (end == 0) end = -3;
   newtok(p);
   while ((c = nextc(p)) != end || nest_level != 0) {
     if (hinf && (c == '\n' || c < 0)) {
@@ -3928,7 +3948,12 @@ parse_string(parser_state *p)
           }
         }
         if ((len-1 == hinf->term_len) && (strncmp(s, hinf->term, len-1) == 0)) {
-          return tHEREDOC_END;
+          if (c < 0) {
+            p->parsing_heredoc = NULL;
+          }
+          else {
+            return tHEREDOC_END;
+          }
         }
       }
       if (c < 0) {
@@ -3969,6 +3994,20 @@ parse_string(parser_state *p)
           tokadd(p, '\\');
           tokadd(p, c);
         }
+        else if (c == 'u' && peek(p, '{')) {
+          /* \u{xxxx xxxx xxxx} form */
+          nextc(p);
+          while (1) {
+            do c = nextc(p); while (ISSPACE(c));
+            if (c == '}') break;
+            pushback(p, c);
+            c = read_escape_unicode(p, 8);
+            if (c < 0) break;
+            tokadd(p, -c);
+          }
+          if (hinf)
+            hinf->line_head = FALSE;
+        }
         else {
           pushback(p, c);
           tokadd(p, read_escape(p));
@@ -4093,10 +4132,12 @@ parse_string(parser_state *p)
     return tREGEXP;
   }
   yylval.nd = new_str(p, tok(p), toklen(p));
-  if (IS_LABEL_SUFFIX(0)) {
-    p->lstate = EXPR_BEG;
-    nextc(p);
-    return tLABEL_END;
+  if (IS_LABEL_POSSIBLE()) {
+    if (IS_LABEL_SUFFIX(0)) {
+      p->lstate = EXPR_BEG;
+      nextc(p);
+      return tLABEL_END;
+    }
   }
 
   return tSTRING;
@@ -4871,7 +4912,7 @@ parser_yylex(parser_state *p)
       char *endp;
 
       errno = 0;
-      d = strtod(tok(p), &endp);
+      d = mrb_float_read(tok(p), &endp);
       if (d == 0 && endp == tok(p)) {
         yywarning_s(p, "corrupted float value %s", tok(p));
       }
@@ -5477,7 +5518,10 @@ mrb_parser_parse(parser_state *p, mrbc_context *c)
     p->lex_strterm = NULL;
 
     parser_init_cxt(p, c);
-    yyparse(p);
+    if (yyparse(p) != 0 || p->nerr > 0) {
+      p->tree = 0;
+      return;
+    }
     if (!p->tree) {
       p->tree = new_nil(p);
     }
@@ -5657,8 +5701,8 @@ mrb_parse_string(mrb_state *mrb, const char *s, mrbc_context *c)
   return mrb_parse_nstring(mrb, s, strlen(s), c);
 }
 
-static mrb_value
-load_exec(mrb_state *mrb, parser_state *p, mrbc_context *c)
+MRB_API mrb_value
+mrb_load_exec(mrb_state *mrb, struct mrb_parser_state *p, mrbc_context *c)
 {
   struct RClass *target = mrb->object_class;
   struct RProc *proc;
@@ -5717,7 +5761,7 @@ load_exec(mrb_state *mrb, parser_state *p, mrbc_context *c)
 MRB_API mrb_value
 mrb_load_file_cxt(mrb_state *mrb, FILE *f, mrbc_context *c)
 {
-  return load_exec(mrb, mrb_parse_file(mrb, f, c), c);
+  return mrb_load_exec(mrb, mrb_parse_file(mrb, f, c), c);
 }
 
 MRB_API mrb_value
@@ -5730,7 +5774,7 @@ mrb_load_file(mrb_state *mrb, FILE *f)
 MRB_API mrb_value
 mrb_load_nstring_cxt(mrb_state *mrb, const char *s, int len, mrbc_context *c)
 {
-  return load_exec(mrb, mrb_parse_nstring(mrb, s, len, c), c);
+  return mrb_load_exec(mrb, mrb_parse_nstring(mrb, s, len, c), c);
 }
 
 MRB_API mrb_value
@@ -6024,7 +6068,17 @@ mrb_parser_dump(mrb_state *mrb, node *tree, int offset)
 
   case NODE_FCALL:
   case NODE_CALL:
-    printf("NODE_CALL:\n");
+  case NODE_SCALL:
+    switch (nodetype) {
+    case NODE_FCALL:
+      printf("NODE_FCALL:\n"); break;
+    case NODE_CALL:
+      printf("NODE_CALL(.):\n"); break;
+    case NODE_SCALL:
+      printf("NODE_SCALL(&.):\n"); break;
+    default:
+      break;
+    }
     mrb_parser_dump(mrb, tree->car, offset+1);
     dump_prefix(tree, offset+1);
     printf("method='%s' (%d)\n",
@@ -6504,8 +6558,8 @@ mrb_parser_dump(mrb_state *mrb, node *tree, int offset)
     break;
 
   case NODE_HEREDOC:
-    printf("NODE_HEREDOC:\n");
-    mrb_parser_dump(mrb, ((parser_heredoc_info*)tree)->doc, offset+1);
+    printf("NODE_HEREDOC (<<%s):\n", ((parser_heredoc_info*)tree)->term);
+    dump_recur(mrb, ((parser_heredoc_info*)tree)->doc, offset+1);
     break;
 
   default:
diff --git a/mrbgems/mruby-enum-ext/mrblib/enum.rb b/mrbgems/mruby-enum-ext/mrblib/enum.rb
index a5f661ce6..113b470a9 100644
--- a/mrbgems/mruby-enum-ext/mrblib/enum.rb
+++ b/mrbgems/mruby-enum-ext/mrblib/enum.rb
@@ -58,13 +58,14 @@ module Enumerable
 
   def take(n)
     raise TypeError, "no implicit conversion of #{n.class} into Integer" unless n.respond_to?(:to_int)
-    raise ArgumentError, "attempt to take negative size" if n < 0
-
-    n = n.to_int
+    i = n.to_int
+    raise ArgumentError, "attempt to take negative size" if i < 0
     ary = []
+    return ary if i == 0
     self.each do |*val|
-      break if ary.size >= n
       ary << val.__svalue
+      i -= 1
+      break if i == 0
     end
     ary
   end
@@ -214,21 +215,28 @@ module Enumerable
   # Returns the first element, or the first +n+ elements, of the enumerable.
   # If the enumerable is empty, the first form returns <code>nil</code>, and the
   # second form returns an empty array.
-  def first(n=NONE)
-    if n == NONE
+  def first(*args)
+    case args.length
+    when 0
       self.each do |*val|
         return val.__svalue
       end
       return nil
-    else
-      a = []
-      i = 0
+    when 1
+      n = args[0]
+      raise TypeError, "no implicit conversion of #{n.class} into Integer" unless n.respond_to?(:to_int)
+      i = n.to_int
+      raise ArgumentError, "attempt to take negative size" if i < 0
+      ary = []
+      return ary if i == 0
       self.each do |*val|
-        break if n<=i
-        a.push val.__svalue
-        i += 1
+        ary << val.__svalue
+        i -= 1
+        break if i == 0
       end
-      a
+      ary
+    else
+      raise ArgumentError, "wrong number of arguments (given #{args.length}, expected 0..1)"
     end
   end
 
@@ -573,35 +581,38 @@ module Enumerable
   #     a.cycle(2) { |x| puts x }  # print, a, b, c, a, b, c.
   #
 
-  def cycle(n=nil, &block)
-    return to_enum(:cycle, n) if !block && n.nil?
+  def cycle(nv = nil, &block)
+    return to_enum(:cycle, nv) unless block
 
-    ary = []
-    if n.nil?
-      self.each do|*val|
-        ary.push val
-        block.call(*val)
+    n = nil
+
+    if nv.nil?
+      n = -1
+    else
+      unless nv.respond_to?(:to_int)
+        raise TypeError, "no implicit conversion of #{nv.class} into Integer"
       end
-      loop do
-        ary.each do|e|
-          block.call(*e)
-        end
+      n = nv.to_int
+      unless n.kind_of?(Integer)
+        raise TypeError, "no implicit conversion of #{nv.class} into Integer"
       end
-    else
-      raise TypeError, "no implicit conversion of #{n.class} into Integer" unless n.respond_to?(:to_int)
+      return nil if n <= 0
+    end
 
-      n = n.to_int
-      self.each do|*val|
-        ary.push val
-      end
-      count = 0
-      while count < n
-        ary.each do|e|
-          block.call(*e)
-        end
-        count += 1
+    ary = []
+    each do |*i|
+      ary.push(i)
+      yield(*i)
+    end
+    return nil if ary.empty?
+
+    while n < 0 || 0 < (n -= 1)
+      ary.each do |i|
+        yield(*i)
       end
     end
+
+    nil
   end
 
   ##
diff --git a/mrbgems/mruby-enum-ext/test/enum.rb b/mrbgems/mruby-enum-ext/test/enum.rb
index 08b553fe5..076562f45 100644
--- a/mrbgems/mruby-enum-ext/test/enum.rb
+++ b/mrbgems/mruby-enum-ext/test/enum.rb
@@ -128,6 +128,13 @@ assert("Enumerable#cycle") do
   ["a", "b", "c"].cycle(2) { |v| a << v }
   assert_equal ["a", "b", "c", "a", "b", "c"], a
   assert_raise(TypeError) { ["a", "b", "c"].cycle("a") { |v| a << v } }
+
+  empty = Class.new do
+    include Enumerable
+    def each
+    end
+  end
+  assert_nil empty.new.cycle { break :nope }
 end
 
 assert("Enumerable#find_index") do
diff --git a/mrbgems/mruby-enum-lazy/mrbgem.rake b/mrbgems/mruby-enum-lazy/mrbgem.rake
index 219141e98..682134c41 100644
--- a/mrbgems/mruby-enum-lazy/mrbgem.rake
+++ b/mrbgems/mruby-enum-lazy/mrbgem.rake
@@ -1,7 +1,7 @@
 MRuby::Gem::Specification.new('mruby-enum-lazy') do |spec|
   spec.license = 'MIT'
   spec.author  = 'mruby developers'
-  spec.summary = 'Enumerable::Lazy class'
+  spec.summary = 'Enumerator::Lazy class'
   spec.add_dependency('mruby-enumerator', :core => 'mruby-enumerator')
   spec.add_dependency('mruby-enum-ext', :core => 'mruby-enum-ext')
 end
diff --git a/mrbgems/mruby-enum-lazy/mrblib/lazy.rb b/mrbgems/mruby-enum-lazy/mrblib/lazy.rb
index 8ce363c6d..b650072e2 100644
--- a/mrbgems/mruby-enum-lazy/mrblib/lazy.rb
+++ b/mrbgems/mruby-enum-lazy/mrblib/lazy.rb
@@ -2,7 +2,7 @@ module Enumerable
 
   # = Enumerable#lazy implementation
   #
-  # Enumerable#lazy returns an instance of Enumerable::Lazy.
+  # Enumerable#lazy returns an instance of Enumerator::Lazy.
   # You can use it just like as normal Enumerable object,
   # except these methods act as 'lazy':
   #
@@ -16,9 +16,11 @@ module Enumerable
   #   - flat_map  collect_concat
   #   - zip
   def lazy
-    Lazy.new(self)
+    Enumerator::Lazy.new(self)
   end
+end
 
+class Enumerator
   # == Acknowledgements
   #
   #   Based on https://github.com/yhara/enumerable-lazy
@@ -40,6 +42,15 @@ module Enumerable
       }
     end
 
+    def to_enum(meth=:each, *args, &block)
+      lz = Lazy.new(self, &block)
+      lz.obj = self
+      lz.meth = meth
+      lz.args = args
+      lz
+    end
+    alias enum_for to_enum
+
     def map(&block)
       Lazy.new(self){|yielder, val|
         yielder << block.call(val)
diff --git a/mrbgems/mruby-enum-lazy/test/lazy.rb b/mrbgems/mruby-enum-lazy/test/lazy.rb
index ca009d34c..940d070e8 100644
--- a/mrbgems/mruby-enum-lazy/test/lazy.rb
+++ b/mrbgems/mruby-enum-lazy/test/lazy.rb
@@ -1,9 +1,9 @@
-assert("Enumerable::Lazy") do
+assert("Enumerator::Lazy") do
   a = [1, 2]
-  assert_equal Enumerable::Lazy, a.lazy.class
+  assert_equal Enumerator::Lazy, a.lazy.class
 end
 
-assert("Enumerable::Lazy laziness") do
+assert("Enumerator::Lazy laziness") do
   a = Object.new
   def a.each
     return to_enum :each unless block_given?
@@ -40,7 +40,13 @@ assert("Enumerable::Lazy laziness") do
   assert_equal [10,20], a.b
 end
 
-assert("Enumerable::Lazy#zip with cycle") do
+assert("Enumrator::Lazy#to_enum") do
+  lazy_enum = (0..Float::INFINITY).lazy.to_enum(:each_slice, 2)
+  assert_kind_of Enumerator::Lazy, lazy_enum
+  assert_equal [0*1, 2*3, 4*5, 6*7], lazy_enum.map { |a| a.first * a.last }.first(4)
+end
+
+assert("Enumerator::Lazy#zip with cycle") do
   e1 = [1, 2, 3].cycle
   e2 = [:a, :b].cycle
   assert_equal [[1,:a],[2,:b],[3,:a]], e1.lazy.zip(e2).first(3)
diff --git a/mrbgems/mruby-enumerator/mrblib/enumerator.rb b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
index 9abaca38a..89b66cd45 100644
--- a/mrbgems/mruby-enumerator/mrblib/enumerator.rb
+++ b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
@@ -153,12 +153,18 @@ class Enumerator
   #
   def with_index(offset=0)
     return to_enum :with_index, offset unless block_given?
-    raise TypeError, "no implicit conversion of #{offset.class} into Integer" unless offset.respond_to?(:to_int)
+    offset = if offset.nil?
+      0
+    elsif offset.respond_to?(:to_int)
+      offset.to_int
+    else
+      raise TypeError, "no implicit conversion of #{offset.class} into Integer"
+    end
 
-    n = offset.to_int - 1
-    enumerator_block_call do |i|
+    n = offset - 1
+    enumerator_block_call do |*i|
       n += 1
-      yield [i,n]
+      yield i.__svalue, n
     end
   end
 
@@ -516,6 +522,7 @@ class Enumerator
 
   # just for internal
   class Generator
+    include Enumerable
     def initialize(&block)
       raise TypeError, "wrong argument type #{self.class} (expected Proc)" unless block.kind_of? Proc
 
diff --git a/mrbgems/mruby-enumerator/test/enumerator.rb b/mrbgems/mruby-enumerator/test/enumerator.rb
index 2e45dae4b..e86e874f0 100644
--- a/mrbgems/mruby-enumerator/test/enumerator.rb
+++ b/mrbgems/mruby-enumerator/test/enumerator.rb
@@ -50,6 +50,9 @@ end
 assert 'Enumerator#with_index' do
   assert_equal([[1,0],[2,1],[3,2]], @obj.to_enum(:foo, 1, 2, 3).with_index.to_a)
   assert_equal([[1,5],[2,6],[3,7]], @obj.to_enum(:foo, 1, 2, 3).with_index(5).to_a)
+  a = []
+  @obj.to_enum(:foo, 1, 2, 3).with_index(10).with_index(20) { |*i| a << i }
+  assert_equal [[[1, 10], 20], [[2, 11], 21], [[3, 12], 22]], a
 end
 
 assert 'Enumerator#with_index nonnum offset' do
diff --git a/mrbgems/mruby-eval/src/eval.c b/mrbgems/mruby-eval/src/eval.c
index 26dd728ba..81bc80280 100644
--- a/mrbgems/mruby-eval/src/eval.c
+++ b/mrbgems/mruby-eval/src/eval.c
@@ -5,6 +5,9 @@
 #include <mruby/proc.h>
 #include <mruby/opcode.h>
 
+mrb_value mrb_exec_irep(mrb_state *mrb, mrb_value self, struct RProc *p);
+mrb_value mrb_obj_instance_eval(mrb_state *mrb, mrb_value self);
+
 static struct mrb_irep *
 get_closure_irep(mrb_state *mrb, int level)
 {
@@ -209,22 +212,15 @@ f_eval(mrb_state *mrb, mrb_value self)
   mrb_value binding = mrb_nil_value();
   char *file = NULL;
   mrb_int line = 1;
-  mrb_value ret;
   struct RProc *proc;
 
   mrb_get_args(mrb, "s|ozi", &s, &len, &binding, &file, &line);
 
   proc = create_proc_from_string(mrb, s, len, binding, file, line);
-  ret = mrb_top_run(mrb, proc, mrb->c->stack[0], 0);
-  if (mrb->exc) {
-    mrb_exc_raise(mrb, mrb_obj_value(mrb->exc));
-  }
-
-  return ret;
+  mrb_assert(!MRB_PROC_CFUNC_P(proc));
+  return mrb_exec_irep(mrb, self, proc);
 }
 
-mrb_value mrb_obj_instance_eval(mrb_state *mrb, mrb_value self);
-
 #define CI_ACC_SKIP    -1
 
 static mrb_value
@@ -250,7 +246,8 @@ f_instance_eval(mrb_state *mrb, mrb_value self)
     c->ci->target_class = mrb_class_ptr(cv);
     proc = create_proc_from_string(mrb, s, len, mrb_nil_value(), file, line);
     mrb->c->ci->env = NULL;
-    return mrb_vm_run(mrb, proc, mrb->c->stack[0], 0);
+    mrb_assert(!MRB_PROC_CFUNC_P(proc));
+    return mrb_exec_irep(mrb, self, proc);
   }
   else {
     mrb_get_args(mrb, "&", &b);
diff --git a/mrbgems/mruby-inline-struct/mrbgem.rake b/mrbgems/mruby-inline-struct/mrbgem.rake
new file mode 100644
index 000000000..91ad9f44b
--- /dev/null
+++ b/mrbgems/mruby-inline-struct/mrbgem.rake
@@ -0,0 +1,5 @@
+MRuby::Gem::Specification.new('mruby-inline-struct') do |spec|
+  spec.license = 'MIT'
+  spec.author  = 'mruby developers'
+  spec.summary = 'inline structure'
+end
diff --git a/mrbgems/mruby-inline-struct/test/inline.c b/mrbgems/mruby-inline-struct/test/inline.c
new file mode 100644
index 000000000..0baaab617
--- /dev/null
+++ b/mrbgems/mruby-inline-struct/test/inline.c
@@ -0,0 +1,83 @@
+#include <mruby.h>
+#include <mruby/class.h>
+#include <mruby/string.h>
+#include <mruby/istruct.h>
+
+static mrb_value
+istruct_test_initialize(mrb_state *mrb, mrb_value self)
+{
+  char *string = (char*)mrb_istruct_ptr(self);
+  mrb_int size = mrb_istruct_size();
+  mrb_value object;
+  mrb_get_args(mrb, "o", &object);
+
+  if (mrb_float_p(object))
+  {
+    snprintf(string, size, "float(%.3f)", mrb_float(object));
+  }
+  else if (mrb_fixnum_p(object))
+  {
+    snprintf(string, size, "fixnum(%" MRB_PRId ")", mrb_fixnum(object));
+  }
+  else if (mrb_string_p(object))
+  {
+    snprintf(string, size, "string(%s)", mrb_string_value_cstr(mrb, &object));
+  }
+
+  string[size - 1] = 0; // force NULL at the end
+  return self;
+}
+
+static mrb_value
+istruct_test_to_s(mrb_state *mrb, mrb_value self)
+{
+  return mrb_str_new_cstr(mrb, (const char*)mrb_istruct_ptr(self));
+}
+
+static mrb_value
+istruct_test_length(mrb_state *mrb, mrb_value self)
+{
+  return mrb_fixnum_value(mrb_istruct_size());
+}
+
+static mrb_value
+istruct_test_test_receive(mrb_state *mrb, mrb_value self)
+{
+  mrb_value object;
+  mrb_get_args(mrb, "o", &object);
+  if (mrb_obj_class(mrb, object) != mrb_class_get(mrb, "InlineStructTest"))
+  {
+    mrb_raisef(mrb, E_TYPE_ERROR, "Expected InlineStructTest");
+  }
+  return mrb_bool_value(((char*)mrb_istruct_ptr(object))[0] == 's');
+}
+
+static mrb_value
+istruct_test_test_receive_direct(mrb_state *mrb, mrb_value self)
+{
+  char *ptr;
+  mrb_get_args(mrb, "I", &ptr);
+  return mrb_bool_value(ptr[0] == 's');
+}
+
+static mrb_value
+istruct_test_mutate(mrb_state *mrb, mrb_value self)
+{
+  char *ptr = (char*)mrb_istruct_ptr(self);
+  memcpy(ptr, "mutate", 6);
+  return mrb_nil_value();
+}
+
+void mrb_mruby_inline_struct_gem_test(mrb_state *mrb)
+{
+  struct RClass *cls;
+
+  cls = mrb_define_class(mrb, "InlineStructTest", mrb->object_class);
+  MRB_SET_INSTANCE_TT(cls, MRB_TT_ISTRUCT);
+  mrb_define_method(mrb, cls, "initialize", istruct_test_initialize, MRB_ARGS_REQ(1));
+  mrb_define_method(mrb, cls, "to_s", istruct_test_to_s, MRB_ARGS_NONE());
+  mrb_define_method(mrb, cls, "mutate", istruct_test_mutate, MRB_ARGS_NONE());
+  mrb_define_class_method(mrb, cls, "length", istruct_test_length, MRB_ARGS_NONE());
+  mrb_define_class_method(mrb, cls, "test_receive", istruct_test_test_receive, MRB_ARGS_REQ(1));
+  mrb_define_class_method(mrb, cls, "test_receive_direct", istruct_test_test_receive_direct, MRB_ARGS_REQ(1));
+}
diff --git a/mrbgems/mruby-inline-struct/test/inline.rb b/mrbgems/mruby-inline-struct/test/inline.rb
new file mode 100644
index 000000000..495859232
--- /dev/null
+++ b/mrbgems/mruby-inline-struct/test/inline.rb
@@ -0,0 +1,151 @@
+##
+# InlineStruct Test
+
+class InlineStructTest
+  def extra_method
+    :ok
+  end
+
+  def test_ivar_set
+    @var = :ivar
+  end
+
+  def test_ivar_get
+    @vat
+  end
+end
+
+assert('InlineStructTest#dup') do
+  obj = InlineStructTest.new(1)
+  assert_equal obj.to_s, 'fixnum(1)'
+  assert_equal obj.dup.to_s, 'fixnum(1)'
+end
+
+assert('InlineStructTest#clone') do
+  obj = InlineStructTest.new(1)
+  assert_equal obj.to_s, 'fixnum(1)'
+  assert_equal obj.clone.to_s, 'fixnum(1)'
+end
+
+assert('InlineStruct#object_id') do
+  obj1 = InlineStructTest.new(1)
+  obj2 = InlineStructTest.new(1)
+  assert_not_equal obj1, obj2
+  assert_not_equal obj1.object_id, obj2.object_id
+  assert_not_equal obj1.object_id, obj1.dup.object_id
+  assert_not_equal obj1.object_id, obj1.clone.object_id
+end
+
+assert('InlineStructTest#mutate (dup)') do
+  obj1 = InlineStructTest.new("foo")
+  assert_equal obj1.to_s, "string(foo)"
+  obj2 = obj1.dup
+  assert_equal obj2.to_s, "string(foo)"
+  obj1.mutate
+  assert_equal obj1.to_s, "mutate(foo)"
+  assert_equal obj2.to_s, "string(foo)"
+end
+
+assert('InlineStructTest#mutate (clone)') do
+  obj1 = InlineStructTest.new("foo")
+  assert_equal obj1.to_s, "string(foo)"
+  obj2 = obj1.clone
+  assert_equal obj2.to_s, "string(foo)"
+  obj1.mutate
+  assert_equal obj1.to_s, "mutate(foo)"
+  assert_equal obj2.to_s, "string(foo)"
+end
+
+assert('InlineStructTest#test_receive(string)') do
+  assert_equal InlineStructTest.test_receive(InlineStructTest.new('a')), true
+end
+
+assert('InlineStructTest#test_receive(float)') do
+  assert_equal InlineStructTest.test_receive(InlineStructTest.new(1.25)), false
+end
+
+assert('InlineStructTest#test_receive(invalid object)') do
+  assert_raise(TypeError) do
+    InlineStructTest.test_receive([])
+  end
+end
+
+assert('InlineStructTest#test_receive(string)') do
+  assert_equal InlineStructTest.test_receive_direct(InlineStructTest.new('a')), true
+end
+
+assert('InlineStructTest#test_receive(float)') do
+  assert_equal InlineStructTest.test_receive_direct(InlineStructTest.new(1.25)), false
+end
+
+assert('InlineStructTest#test_receive(invalid object)') do
+  assert_raise(TypeError) do
+    InlineStructTest.test_receive_direct([])
+  end
+end
+
+assert('InlineStructTest#extra_method') do
+  assert_equal InlineStructTest.new(1).extra_method, :ok
+end
+
+assert('InlineStructTest instance variable') do
+  obj = InlineStructTest.new(1)
+  assert_raise(ArgumentError) do
+    obj.test_ivar_set
+  end
+  assert_equal obj.test_ivar_get, nil
+end
+
+# 64-bit mode
+if InlineStructTest.length == 24
+  assert('InlineStructTest length [64 bit]') do
+    assert_equal InlineStructTest.length, 3 * 8
+  end
+
+  assert('InlineStructTest w/float [64 bit]') do
+    obj = InlineStructTest.new(1.25)
+    assert_equal obj.to_s, "float(1.250)"
+  end
+
+  assert('InlineStructTest w/fixnum [64 bit]') do
+    obj = InlineStructTest.new(42)
+    assert_equal obj.to_s, "fixnum(42)"
+  end
+
+  assert('InlineStructTest w/string [64 bit]') do
+    obj = InlineStructTest.new("hello")
+    assert_equal obj.to_s, "string(hello)"
+  end
+
+  assert('InlineStructTest w/long string [64 bit]') do
+    obj = InlineStructTest.new("this won't fit in 3 * 8 bytes available for the structure")
+    assert_equal obj.to_s, "string(this won't fit i"
+  end
+end
+
+# 32-bit mode
+if InlineStructTest.length == 12
+  assert('InlineStructTest length [32 bit]') do
+    assert_equal InlineStructTest.length, 3 * 4
+  end
+
+  assert('InlineStructTest w/float [32 bit]') do
+    obj = InlineStructTest.new(1.25)
+    assert_equal obj.to_s, "float(1.250"
+  end
+
+  assert('InlineStructTest w/fixnum [32 bit]') do
+    obj = InlineStructTest.new(42)
+    assert_equal obj.to_s, "fixnum(42)"
+  end
+
+  assert('InlineStructTest w/string [32 bit]') do
+    obj = InlineStructTest.new("hello")
+    assert_equal obj.to_s, "string(hell"
+  end
+
+  assert('InlineStructTest w/long string [32 bit]') do
+    obj = InlineStructTest.new("this won't fit in 3 * 4 bytes available for the structure")
+    assert_equal obj.to_s, "string(this"
+  end
+end
diff --git a/mrbgems/mruby-kernel-ext/src/kernel.c b/mrbgems/mruby-kernel-ext/src/kernel.c
index d2153be4a..7e6fa28bd 100644
--- a/mrbgems/mruby-kernel-ext/src/kernel.c
+++ b/mrbgems/mruby-kernel-ext/src/kernel.c
@@ -2,6 +2,64 @@
 #include <mruby/error.h>
 #include <mruby/array.h>
 #include <mruby/hash.h>
+#include <mruby/range.h>
+
+static mrb_value
+mrb_f_caller(mrb_state *mrb, mrb_value self)
+{
+  mrb_value bt, v, length;
+  mrb_int bt_len, argc, lev, n;
+
+  bt = mrb_get_backtrace(mrb);
+  bt_len = RARRAY_LEN(bt);
+  argc = mrb_get_args(mrb, "|oo", &v, &length);
+
+  switch (argc) {
+    case 0:
+      lev = 1;
+      n = bt_len - lev;
+      break;
+    case 1:
+      if (mrb_type(v) == MRB_TT_RANGE) {
+        mrb_int beg, len;
+        if (mrb_range_beg_len(mrb, v, &beg, &len, bt_len, TRUE) == 1) {
+          lev = beg;
+          n = len;
+        }
+        else {
+          return mrb_nil_value();
+        }
+      }
+      else {
+        v = mrb_to_int(mrb, v);
+        lev = mrb_fixnum(v);
+        if (lev < 0) {
+          mrb_raisef(mrb, E_ARGUMENT_ERROR, "negative level (%S)", v);
+        }
+        n = bt_len - lev;
+      }
+      break;
+    case 2:
+      lev = mrb_fixnum(mrb_to_int(mrb, v));
+      n = mrb_fixnum(mrb_to_int(mrb, length));
+      if (lev < 0) {
+        mrb_raisef(mrb, E_ARGUMENT_ERROR, "negative level (%S)", v);
+      }
+      if (n < 0) {
+        mrb_raisef(mrb, E_ARGUMENT_ERROR, "negative size (%S)", length);
+      }
+      break;
+    default:
+      lev = n = 0;
+      break;
+  }
+
+  if (n == 0) {
+    return mrb_ary_new(mrb);
+  }
+
+  return mrb_funcall(mrb, bt, "[]", 2, mrb_fixnum_value(lev), mrb_fixnum_value(n));
+}
 
 /*
  *  call-seq:
@@ -170,6 +228,7 @@ mrb_mruby_kernel_ext_gem_init(mrb_state *mrb)
   struct RClass *krn = mrb->kernel_module;
 
   mrb_define_module_function(mrb, krn, "fail", mrb_f_raise, MRB_ARGS_OPT(2));
+  mrb_define_module_function(mrb, krn, "caller", mrb_f_caller, MRB_ARGS_OPT(2));
   mrb_define_method(mrb, krn, "__method__", mrb_f_method, MRB_ARGS_NONE());
   mrb_define_module_function(mrb, krn, "Integer", mrb_f_integer, MRB_ARGS_ANY());
   mrb_define_module_function(mrb, krn, "Float", mrb_f_float, MRB_ARGS_REQ(1));
diff --git a/mrbgems/mruby-kernel-ext/test/kernel.rb b/mrbgems/mruby-kernel-ext/test/kernel.rb
index cc6af13a3..dd7cea86a 100644
--- a/mrbgems/mruby-kernel-ext/test/kernel.rb
+++ b/mrbgems/mruby-kernel-ext/test/kernel.rb
@@ -3,6 +3,35 @@ assert('Kernel.fail, Kernel#fail') do
   assert_raise(RuntimeError) { Kernel.fail }
 end
 
+assert('Kernel.caller, Kernel#caller') do
+  skip "backtrace isn't available" if caller(0).empty?
+
+  c = Class.new do
+    def foo(*args)
+      caller(*args)
+    end
+
+    def bar(*args)
+      foo(*args)
+    end
+
+    def baz(*args)
+      bar(*args)
+    end
+  end
+  assert_equal "#bar", c.new.baz[0][-4..-1]
+  assert_equal "#foo", c.new.baz(0)[0][-4..-1]
+  assert_equal "#bar", c.new.baz(1)[0][-4..-1]
+  assert_equal "#baz", c.new.baz(2)[0][-4..-1]
+  assert_equal ["#foo", "#bar"], c.new.baz(0, 2).map { |i| i[-4..-1] }
+  assert_equal ["#bar", "#baz"], c.new.baz(1..2).map { |i| i[-4..-1] }
+  assert_nil c.new.baz(10..20)
+  assert_raise(ArgumentError) { c.new.baz(-1) }
+  assert_raise(ArgumentError) { c.new.baz(-1, 1) }
+  assert_raise(ArgumentError) { c.new.baz(1, -1) }
+  assert_raise(TypeError) { c.new.baz(nil) }
+end
+
 assert('Kernel#__method__') do
   assert_equal(:m, Class.new {def m; __method__; end}.new.m)
   assert_equal(:m, Class.new {define_method(:m) {__method__}}.new.m)
diff --git a/mrbgems/mruby-object-ext/src/object.c b/mrbgems/mruby-object-ext/src/object.c
index 3eba95633..e4fe328e9 100644
--- a/mrbgems/mruby-object-ext/src/object.c
+++ b/mrbgems/mruby-object-ext/src/object.c
@@ -96,7 +96,7 @@ mrb_mruby_object_ext_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, n, "to_f", nil_to_f,       MRB_ARGS_NONE());
   mrb_define_method(mrb, n, "to_i", nil_to_i,       MRB_ARGS_NONE());
 
-  mrb_define_method(mrb, mrb->object_class, "instance_exec", mrb_obj_instance_exec, MRB_ARGS_ANY() | MRB_ARGS_BLOCK());
+  mrb_define_method(mrb, mrb->kernel_module, "instance_exec", mrb_obj_instance_exec, MRB_ARGS_ANY() | MRB_ARGS_BLOCK());
 }
 
 void
diff --git a/mrbgems/mruby-object-ext/test/object.rb b/mrbgems/mruby-object-ext/test/object.rb
index fe56f1ec5..f0742f8ce 100644
--- a/mrbgems/mruby-object-ext/test/object.rb
+++ b/mrbgems/mruby-object-ext/test/object.rb
@@ -23,3 +23,31 @@ assert('Object#tap') do
   ], ret
   assert_equal(:tap_ok, Class.new {def m; tap{return :tap_ok}; end}.new.m)
 end
+
+assert('instance_exec on primitives with class and module definition') do
+  begin
+    class A
+      1.instance_exec do
+        class B
+        end
+      end
+    end
+
+    assert_kind_of Class, A::B
+  ensure
+    Object.remove_const :A
+  end
+
+  begin
+    class A
+      1.instance_exec do
+        module B
+        end
+      end
+    end
+
+    assert_kind_of Module, A::B
+  ensure
+    Object.remove_const :A
+  end
+end
diff --git a/mrbgems/mruby-objectspace/src/mruby_objectspace.c b/mrbgems/mruby-objectspace/src/mruby_objectspace.c
index d5cd4f5a1..d0a8effd0 100644
--- a/mrbgems/mruby-objectspace/src/mruby_objectspace.c
+++ b/mrbgems/mruby-objectspace/src/mruby_objectspace.c
@@ -49,7 +49,7 @@ static mrb_value
 os_count_objects(mrb_state *mrb, mrb_value self)
 {
   struct os_count_struct obj_count = { 0 };
-  enum mrb_vtype i;
+  mrb_int i;
   mrb_value hash;
 
   if (mrb_get_args(mrb, "|H", &hash) == 0) {
diff --git a/mrbgems/mruby-print/src/print.c b/mrbgems/mruby-print/src/print.c
index da5f36789..fd8d15241 100644
--- a/mrbgems/mruby-print/src/print.c
+++ b/mrbgems/mruby-print/src/print.c
@@ -22,7 +22,7 @@ printstr(mrb_state *mrb, mrb_value obj)
       int mlen = RSTRING_LEN(obj);
       char* utf8 = RSTRING_PTR(obj);
       int wlen = MultiByteToWideChar(CP_UTF8, 0, utf8, mlen, NULL, 0);
-      wchar_t* utf16 = mrb_malloc(mrb, (wlen+1) * sizeof(wchar_t));
+      wchar_t* utf16 = (wchar_t*)mrb_malloc(mrb, (wlen+1) * sizeof(wchar_t));
       if (utf16 == NULL) return;
       if (MultiByteToWideChar(CP_UTF8, 0, utf8, mlen, utf16, wlen) > 0) {
         utf16[wlen] = 0;
diff --git a/mrbgems/mruby-proc-ext/src/proc.c b/mrbgems/mruby-proc-ext/src/proc.c
index c8c8f1aa1..34f6230dc 100644
--- a/mrbgems/mruby-proc-ext/src/proc.c
+++ b/mrbgems/mruby-proc-ext/src/proc.c
@@ -114,6 +114,9 @@ mrb_proc_parameters(mrb_state *mrb, mrb_value self)
     // TODO cfunc aspec is not implemented yet
     return mrb_ary_new(mrb);
   }
+  if (!irep) {
+    return mrb_ary_new(mrb);
+  }
   if (!irep->lv) {
     return mrb_ary_new(mrb);
   }
diff --git a/mrbgems/mruby-random/src/random.c b/mrbgems/mruby-random/src/random.c
index 3b8d0dd2f..f81d38fe6 100644
--- a/mrbgems/mruby-random/src/random.c
+++ b/mrbgems/mruby-random/src/random.c
@@ -124,6 +124,8 @@ mrb_random_init(mrb_state *mrb, mrb_value self)
   mrb_value seed;
   mt_state *t;
 
+  seed = get_opt(mrb);
+
   /* avoid memory leaks */
   t = (mt_state*)DATA_PTR(self);
   if (t) {
@@ -134,7 +136,6 @@ mrb_random_init(mrb_state *mrb, mrb_value self)
   t = (mt_state *)mrb_malloc(mrb, sizeof(mt_state));
   t->mti = N + 1;
 
-  seed = get_opt(mrb);
   seed = mrb_random_mt_srand(mrb, t, seed);
   if (mrb_nil_p(seed)) {
     t->has_seed = FALSE;
@@ -266,7 +267,7 @@ mrb_ary_sample(mrb_state *mrb, mrb_value ary)
   mrb_int n = 0;
   mrb_bool given;
   mt_state *random = NULL;
-  mrb_int len = RARRAY_LEN(ary);
+  mrb_int len;
 
   mrb_get_args(mrb, "|i?d", &n, &given, &random, &mt_state_type);
   if (random == NULL) {
@@ -274,6 +275,7 @@ mrb_ary_sample(mrb_state *mrb, mrb_value ary)
   }
   mrb_random_rand_seed(mrb, random);
   mt_rand(random);
+  len = RARRAY_LEN(ary);
   if (!given) {                 /* pick one element */
     switch (len) {
     case 0:
diff --git a/mrbgems/mruby-random/test/random.rb b/mrbgems/mruby-random/test/random.rb
index 1653ae4a6..1c59be3a6 100644
--- a/mrbgems/mruby-random/test/random.rb
+++ b/mrbgems/mruby-random/test/random.rb
@@ -74,3 +74,15 @@ assert('Array#shuffle!(random)') do
 
   ary1 != [1, 2, 3, 4, 5, 6, 7, 8, 9, 10] and 10.times { |x| ary1.include? x } and ary1 == ary2
 end
+
+assert('Array#sample checks input length after reading arguments') do
+  $ary = [1, 2, 3]
+  class ArrayChange
+    def to_i
+      $ary << 4
+      4
+    end
+  end
+
+  assert_equal [1, 2, 3, 4], $ary.sample(ArrayChange.new).sort
+end
diff --git a/mrbgems/mruby-range-ext/mrblib/range.rb b/mrbgems/mruby-range-ext/mrblib/range.rb
new file mode 100644
index 000000000..e5d1fb079
--- /dev/null
+++ b/mrbgems/mruby-range-ext/mrblib/range.rb
@@ -0,0 +1,31 @@
+class Range
+  ##
+  # call-seq:
+  #    rng.first    -> obj
+  #    rng.first(n) -> an_array
+  #
+  # Returns the first object in the range, or an array of the first +n+
+  # elements.
+  #
+  #   (10..20).first     #=> 10
+  #   (10..20).first(3)  #=> [10, 11, 12]
+  #
+  def first(*args)
+    return self.begin if args.empty?
+
+    raise ArgumentError, "wrong number of arguments (given #{args.length}, expected 1)" unless args.length == 1
+    nv = args[0]
+    raise TypeError, "no implicit conversion from nil to integer" if nv.nil?
+    raise TypeError, "no implicit conversion of #{nv.class} into Integer" unless nv.respond_to?(:to_int)
+    n = nv.to_int
+    raise TypeError, "no implicit conversion of #{nv.class} into Integer" unless n.kind_of?(Integer)
+    raise ArgumentError, "negative array size (or size too big)" unless 0 <= n
+    ary = []
+    each do |i|
+      break if n <= 0
+      ary.push(i)
+      n -= 1
+    end
+    ary
+  end
+end
diff --git a/mrbgems/mruby-range-ext/src/range.c b/mrbgems/mruby-range-ext/src/range.c
index 4d6f1684f..3131192ff 100644
--- a/mrbgems/mruby-range-ext/src/range.c
+++ b/mrbgems/mruby-range-ext/src/range.c
@@ -1,6 +1,7 @@
 #include <mruby.h>
 #include <mruby/range.h>
 #include <math.h>
+#include <float.h>
 
 static mrb_bool
 r_le(mrb_state *mrb, mrb_value a, mrb_value b)
@@ -43,7 +44,7 @@ static mrb_value
 mrb_range_cover(mrb_state *mrb, mrb_value range)
 {
   mrb_value val;
-  struct RRange *r = mrb_range_ptr(range);
+  struct RRange *r = mrb_range_ptr(mrb, range);
   mrb_value beg, end;
 
   mrb_get_args(mrb, "o", &val);
@@ -67,32 +68,6 @@ mrb_range_cover(mrb_state *mrb, mrb_value range)
 
 /*
  *  call-seq:
- *     rng.first    -> obj
- *     rng.first(n) -> an_array
- *
- *  Returns the first object in the range, or an array of the first +n+
- *  elements.
- *
- *    (10..20).first     #=> 10
- *    (10..20).first(3)  #=> [10, 11, 12]
- */
-static mrb_value
-mrb_range_first(mrb_state *mrb, mrb_value range)
-{
-  mrb_int num;
-  mrb_value array;
-  struct RRange *r = mrb_range_ptr(range);
-
-  if (mrb_get_args(mrb, "|i", &num) == 0) {
-    return r->edges->beg;
-  }
-
-  array = mrb_funcall(mrb, range, "to_a", 0);
-  return mrb_funcall(mrb, array, "first", 1, mrb_fixnum_value(num));
-}
-
-/*
- *  call-seq:
  *     rng.last    -> obj
  *     rng.last(n) -> an_array
  *
@@ -112,7 +87,7 @@ mrb_range_last(mrb_state *mrb, mrb_value range)
 {
   mrb_value num;
   mrb_value array;
-  struct RRange *r = mrb_range_ptr(range);
+  struct RRange *r = mrb_range_ptr(mrb, range);
 
   if (mrb_get_args(mrb, "|o", &num) == 0) {
     return r->edges->end;
@@ -136,15 +111,17 @@ mrb_range_last(mrb_state *mrb, mrb_value range)
 static mrb_value
 mrb_range_size(mrb_state *mrb, mrb_value range)
 {
-  struct RRange *r = mrb_range_ptr(range);
+  struct RRange *r = mrb_range_ptr(mrb, range);
   mrb_value beg, end;
-  double beg_f, end_f;
+  mrb_float beg_f, end_f;
   mrb_bool num_p = TRUE;
+  mrb_bool excl;
 
   beg = r->edges->beg;
   end = r->edges->end;
+  excl = r->excl;
   if (mrb_fixnum_p(beg)) {
-    beg_f = (double)mrb_fixnum(beg);
+    beg_f = (mrb_float)mrb_fixnum(beg);
   }
   else if (mrb_float_p(beg)) {
     beg_f = mrb_float(beg);
@@ -153,7 +130,7 @@ mrb_range_size(mrb_state *mrb, mrb_value range)
     num_p = FALSE;
   }
   if (mrb_fixnum_p(end)) {
-    end_f = (double)mrb_fixnum(end);
+    end_f = (mrb_float)mrb_fixnum(end);
   }
   else if (mrb_float_p(end)) {
     end_f = mrb_float(end);
@@ -162,14 +139,24 @@ mrb_range_size(mrb_state *mrb, mrb_value range)
     num_p = FALSE;
   }
   if (num_p) {
-    double f;
-
-    if (beg_f > end_f) return mrb_fixnum_value(0);
-    f = end_f - beg_f;
-    if (!r->excl) {
-      return mrb_fixnum_value((mrb_int)ceil(f + 1));
+    mrb_float n = end_f - beg_f;
+    mrb_float err = (fabs(beg_f) + fabs(end_f) + fabs(end_f-beg_f)) * MRB_FLOAT_EPSILON;
+
+    if (err>0.5) err=0.5;
+    if (excl) {
+      if (n<=0) return mrb_fixnum_value(0);
+      if (n<1)
+        n = 0;
+      else
+        n = floor(n - err);
+    }
+    else {
+      if (n<0) return mrb_fixnum_value(0);
+      n = floor(n + err);
     }
-    return mrb_fixnum_value((mrb_int)ceil(f));
+    if (isinf(n+1))
+      return mrb_float_value(mrb, INFINITY);
+    return mrb_fixnum_value((mrb_int)n+1);
   }
   return mrb_nil_value();
 }
@@ -180,7 +167,6 @@ mrb_mruby_range_ext_gem_init(mrb_state* mrb)
   struct RClass * s = mrb_class_get(mrb, "Range");
 
   mrb_define_method(mrb, s, "cover?", mrb_range_cover, MRB_ARGS_REQ(1));
-  mrb_define_method(mrb, s, "first",  mrb_range_first, MRB_ARGS_OPT(1));
   mrb_define_method(mrb, s, "last",   mrb_range_last,  MRB_ARGS_OPT(1));
   mrb_define_method(mrb, s, "size",   mrb_range_size,  MRB_ARGS_NONE());
 }
diff --git a/mrbgems/mruby-range-ext/test/range.rb b/mrbgems/mruby-range-ext/test/range.rb
index 18e7dafe4..efcbdabe4 100644
--- a/mrbgems/mruby-range-ext/test/range.rb
+++ b/mrbgems/mruby-range-ext/test/range.rb
@@ -10,6 +10,7 @@ end
 assert('Range#first') do
   assert_equal 10, (10..20).first
   assert_equal [10, 11, 12], (10..20).first(3)
+  assert_equal [0, 1, 2], (0..Float::INFINITY).first(3)
 end
 
 assert('Range#last') do
@@ -25,5 +26,7 @@ assert('Range#size') do
   assert_equal 6, (1...6.3).size
   assert_equal 5, (1...6.0).size
   assert_equal 5, (1.1...6).size
+  assert_equal 15, (1.0..15.9).size
+  assert_equal Float::INFINITY, (0..Float::INFINITY).size
   assert_nil ('a'..'z').size
 end
diff --git a/mrbgems/mruby-sprintf/src/sprintf.c b/mrbgems/mruby-sprintf/src/sprintf.c
index 8d14b0fc5..d02a2aa4d 100644
--- a/mrbgems/mruby-sprintf/src/sprintf.c
+++ b/mrbgems/mruby-sprintf/src/sprintf.c
@@ -116,8 +116,9 @@ mrb_fix2binstr(mrb_state *mrb, mrb_value x, int base)
 
 #define CHECK(l) do {\
 /*  int cr = ENC_CODERANGE(result);*/\
-  while (blen + (l) >= bsiz) {\
+  while ((l) >= bsiz - blen) {\
     bsiz*=2;\
+    if (bsiz < 0) mrb_raise(mrb, E_ARGUMENT_ERROR, "too big specifier"); \
   }\
   mrb_str_resize(mrb, result, bsiz);\
 /*  ENC_CODERANGE_SET(result, cr);*/\
@@ -136,29 +137,63 @@ mrb_fix2binstr(mrb_state *mrb, mrb_value x, int base)
   blen += (l);\
 } while (0)
 
-#define GETARG() (!mrb_undef_p(nextvalue) ? nextvalue : \
-  posarg == -1 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "unnumbered(%S) mixed with numbered", mrb_fixnum_value(nextarg)), mrb_undef_value()) : \
-  posarg == -2 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "unnumbered(%S) mixed with named", mrb_fixnum_value(nextarg)), mrb_undef_value()) : \
+static void
+check_next_arg(mrb_state *mrb, int posarg, int nextarg)
+{
+  switch (posarg) {
+  case -1:
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "unnumbered(%S) mixed with numbered", mrb_fixnum_value(nextarg));
+    break;
+  case -2:
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "unnumbered(%S) mixed with named", mrb_fixnum_value(nextarg));
+    break;
+  default:
+    break;
+  }
+}
+
+static void
+check_pos_arg(mrb_state *mrb, int posarg, int n)
+{
+  if (posarg > 0) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "numbered(%S) after unnumbered(%S)",
+               mrb_fixnum_value(n), mrb_fixnum_value(posarg));
+  }
+  if (posarg == -2) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "numbered(%S) after named", mrb_fixnum_value(n));
+  }
+  if (n < 1) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "invalid index - %S$", mrb_fixnum_value(n));
+  }
+}
+
+static void
+check_name_arg(mrb_state *mrb, int posarg, const char *name, int len)
+{
+  if (posarg > 0) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "named%S after unnumbered(%S)",
+               mrb_str_new(mrb, (name), (len)), mrb_fixnum_value(posarg));
+  }
+  if (posarg == -1) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "named%S after numbered", mrb_str_new(mrb, (name), (len)));
+  }
+}
+
+#define GETNEXTARG() (\
+  check_next_arg(mrb, posarg, nextarg),\
   (posarg = nextarg++, GETNTHARG(posarg)))
 
-#define GETPOSARG(n) (posarg > 0 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "numbered(%S) after unnumbered(%S)", mrb_fixnum_value(n), mrb_fixnum_value(posarg)), mrb_undef_value()) : \
-  posarg == -2 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "numbered(%S) after named", mrb_fixnum_value(n)), mrb_undef_value()) : \
-  ((n < 1) ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "invalid index - %S$", mrb_fixnum_value(n)), mrb_undef_value()) : \
-  (posarg = -1, GETNTHARG(n))))
+#define GETARG() (!mrb_undef_p(nextvalue) ? nextvalue : GETNEXTARG())
+
+#define GETPOSARG(n) (\
+  check_pos_arg(mrb, posarg, n),\
+  (posarg = -1, GETNTHARG(n)))
 
 #define GETNTHARG(nth) \
   ((nth >= argc) ? (mrb_raise(mrb, E_ARGUMENT_ERROR, "too few arguments"), mrb_undef_value()) : argv[nth])
 
-#define GETNAMEARG(id, name, len) ( \
-  posarg > 0 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "named%S after unnumbered(%S)", mrb_str_new(mrb, (name), (len)), mrb_fixnum_value(posarg)), mrb_undef_value()) : \
-  posarg == -1 ? \
-  (mrb_raisef(mrb, E_ARGUMENT_ERROR, "named%S after numbered", mrb_str_new(mrb, (name), (len))), mrb_undef_value()) :    \
+#define GETNAMEARG(id, name, len) (\
+  check_name_arg(mrb, posarg, name, len),\
   (posarg = -2, mrb_hash_fetch(mrb, get_hash(mrb, &hash, argc, argv), id, mrb_undef_value())))
 
 #define GETNUM(n, val) \
@@ -182,7 +217,7 @@ mrb_fix2binstr(mrb_state *mrb, mrb_value x, int base)
     tmp_v = GETPOSARG(n); \
   } \
   else { \
-    tmp_v = GETARG(); \
+    tmp_v = GETNEXTARG(); \
     p = t; \
   } \
   num = mrb_fixnum(tmp_v); \
@@ -675,6 +710,7 @@ retry:
         else {
           mrb_raise(mrb, E_ARGUMENT_ERROR, "invalid character");
         }
+        mrb_check_type(mrb, tmp, MRB_TT_STRING);
         c = RSTRING_PTR(tmp);
         n = RSTRING_LEN(tmp);
         if (!(flags & FWIDTH)) {
@@ -686,10 +722,10 @@ retry:
           CHECK(n);
           memcpy(buf+blen, c, n);
           blen += n;
-          FILL(' ', width-1);
+          if (width>0) FILL(' ', width-1);
         }
         else {
-          FILL(' ', width-1);
+          if (width>0) FILL(' ', width-1);
           CHECK(n);
           memcpy(buf+blen, c, n);
           blen += n;
@@ -843,20 +879,20 @@ retry:
             strncpy(nbuf, RSTRING_PTR(val), sizeof(nbuf));
             break;
           case 8:
-            snprintf(nbuf, sizeof(nbuf), "%"MRB_PRIo, v);
+            snprintf(nbuf, sizeof(nbuf), "%" MRB_PRIo, v);
             break;
           case 10:
-            snprintf(nbuf, sizeof(nbuf), "%"MRB_PRId, v);
+            snprintf(nbuf, sizeof(nbuf), "%" MRB_PRId, v);
             break;
           case 16:
-            snprintf(nbuf, sizeof(nbuf), "%"MRB_PRIx, v);
+            snprintf(nbuf, sizeof(nbuf), "%" MRB_PRIx, v);
             break;
           }
           s = nbuf;
         }
         else {
           s = nbuf;
-          if (v < 0) {
+          if (base != 10 && v < 0) {
             dots = 1;
           }
           switch (base) {
@@ -864,13 +900,13 @@ retry:
             strncpy(++s, RSTRING_PTR(val), sizeof(nbuf)-1);
             break;
           case 8:
-            snprintf(++s, sizeof(nbuf)-1, "%"MRB_PRIo, v);
+            snprintf(++s, sizeof(nbuf)-1, "%" MRB_PRIo, v);
             break;
           case 10:
-            snprintf(++s, sizeof(nbuf)-1, "%"MRB_PRId, v);
+            snprintf(++s, sizeof(nbuf)-1, "%" MRB_PRId, v);
             break;
           case 16:
-            snprintf(++s, sizeof(nbuf)-1, "%"MRB_PRIx, v);
+            snprintf(++s, sizeof(nbuf)-1, "%" MRB_PRIx, v);
             break;
           }
           if (v < 0) {
diff --git a/mrbgems/mruby-sprintf/test/sprintf.rb b/mrbgems/mruby-sprintf/test/sprintf.rb
index 454c226e1..ccbd95d51 100644
--- a/mrbgems/mruby-sprintf/test/sprintf.rb
+++ b/mrbgems/mruby-sprintf/test/sprintf.rb
@@ -5,5 +5,28 @@ assert('String#%') do
   assert_equal "one=1", "one=%d" % 1
   assert_equal "1 one 1.0", "%d %s %3.1f" % [ 1, "one", 1.01 ]
   assert_equal "123 < 456", "%{num} < %<str>s" % { num: 123, str: "456" }
-  assert_equal 16, ("%b" % (1<<15)).size
+  assert_equal 15, ("%b" % (1<<14)).size
+end
+
+assert("String#% with invalid chr") do
+  begin
+    class Fixnum
+      alias_method :chr_, :chr if method_defined?(:chr)
+
+      def chr
+        nil
+      end
+    end
+
+    assert_raise TypeError do
+      "%c" % 0
+    end
+  ensure
+    class Fixnum
+      if method_defined?(:chr_)
+        alias_method :chr, :chr_
+        remove_method :chr_
+      end
+    end
+  end
 end
diff --git a/mrbgems/mruby-string-ext/mrblib/string.rb b/mrbgems/mruby-string-ext/mrblib/string.rb
index c3b765a5f..8895b7ad3 100644
--- a/mrbgems/mruby-string-ext/mrblib/string.rb
+++ b/mrbgems/mruby-string-ext/mrblib/string.rb
@@ -45,7 +45,7 @@ class String
   def lstrip
     a = 0
     z = self.size - 1
-    a += 1 while " \f\n\r\t\v".include?(self[a]) and a <= z
+    a += 1 while a <= z and " \f\n\r\t\v".include?(self[a])
     (z >= 0) ? self[a..z] : ""
   end
 
@@ -62,7 +62,7 @@ class String
   def rstrip
     a = 0
     z = self.size - 1
-    z -= 1 while " \f\n\r\t\v\0".include?(self[z]) and a <= z
+    z -= 1 while a <= z and " \f\n\r\t\v\0".include?(self[z])
     (z >= 0) ? self[a..z] : ""
   end
 
@@ -78,8 +78,8 @@ class String
   def strip
     a = 0
     z = self.size - 1
-    a += 1 while " \f\n\r\t\v".include?(self[a]) and a <= z
-    z -= 1 while " \f\n\r\t\v\0".include?(self[z]) and a <= z
+    a += 1 while a <= z and " \f\n\r\t\v".include?(self[a])
+    z -= 1 while a <= z and " \f\n\r\t\v\0".include?(self[z])
     (z >= 0) ? self[a..z] : ""
   end
 
@@ -275,15 +275,11 @@ class String
   #     "hello".ljust(20)           #=> "hello               "
   #     "hello".ljust(20, '1234')   #=> "hello123412341234123"
   def ljust(idx, padstr = ' ')
-    if idx <= self.size
-      return self
-    end
-    newstr = self.dup
-    newstr << padstr
-    while newstr.size <= idx
-      newstr << padstr
-    end
-    return newstr.slice(0,idx)
+    raise ArgumentError, 'zero width padding' if padstr == ''
+    return self if idx <= self.size
+    pad_repetitions = (idx / padstr.length).ceil
+    padding = (padstr * pad_repetitions)[0...(idx - self.length)]
+    self + padding
   end
 
   ##
@@ -298,15 +294,11 @@ class String
   #     "hello".rjust(20)           #=> "               hello"
   #     "hello".rjust(20, '1234')   #=> "123412341234123hello"
   def rjust(idx, padstr = ' ')
-    if idx <= self.size
-      return self
-    end
-      padsize = idx - self.size
-      newstr = padstr.dup
-      while newstr.size <= padsize
-        newstr << padstr
-      end
-    return newstr.slice(0,padsize) + self
+    raise ArgumentError, 'zero width padding' if padstr == ''
+    return self if idx <= self.size
+    pad_repetitions = (idx / padstr.length).ceil
+    padding = (padstr * pad_repetitions)[0...(idx - self.length)]
+    padding + self
   end
 
   #     str.upto(other_str, exclusive=false) {|s| block }   -> str
@@ -385,4 +377,18 @@ class String
     end
   end
   alias each_codepoint codepoints
+
+  ##
+  # call-seq:
+  #    str.prepend(other_str)  -> str
+  #
+  # Prepend---Prepend the given string to <i>str</i>.
+  #
+  #    a = "world"
+  #    a.prepend("hello ") #=> "hello world"
+  #    a                   #=> "hello world"
+  def prepend(arg)
+    self[0, 0] = arg
+    self
+  end
 end
diff --git a/mrbgems/mruby-string-ext/src/string.c b/mrbgems/mruby-string-ext/src/string.c
index 2a52d53b3..7e87b3db4 100644
--- a/mrbgems/mruby-string-ext/src/string.c
+++ b/mrbgems/mruby-string-ext/src/string.c
@@ -23,10 +23,11 @@ static mrb_value
 mrb_str_setbyte(mrb_state *mrb, mrb_value str)
 {
   mrb_int pos, byte;
-  long len = RSTRING_LEN(str);
+  long len;
 
   mrb_get_args(mrb, "ii", &pos, &byte);
 
+  len = RSTRING_LEN(str);
   if (pos < -len || len <= pos)
     mrb_raisef(mrb, E_INDEX_ERROR, "index %S is out of array", mrb_fixnum_value(pos));
   if (pos < 0)
@@ -55,8 +56,14 @@ mrb_str_byteslice(mrb_state *mrb, mrb_value str)
       mrb_int beg;
 
       len = RSTRING_LEN(str);
-      if (mrb_range_beg_len(mrb, a1, &beg, &len, len)) {
+      switch (mrb_range_beg_len(mrb, a1, &beg, &len, len, TRUE)) {
+      case 0:                   /* not range */
+        break;
+      case 1:                   /* range */
         return mrb_str_substr(mrb, str, beg, len);
+      case 2:                   /* out of range */
+        mrb_raisef(mrb, E_RANGE_ERROR, "%S out of range", a1);
+        break;
       }
       return mrb_nil_value();
     }
@@ -307,13 +314,14 @@ mrb_str_lines(mrb_state *mrb, mrb_value self)
   int ai;
   mrb_int len;
   mrb_value arg;
-  char *p = RSTRING_PTR(self), *t;
-  char *e = p + RSTRING_LEN(self);
+  char *b = RSTRING_PTR(self);
+  char *p = b, *t;
+  char *e = b + RSTRING_LEN(self);
 
   mrb_get_args(mrb, "&", &blk);
 
   result = mrb_ary_new(mrb);
-
+  ai = mrb_gc_arena_save(mrb);
   if (!mrb_nil_p(blk)) {
     while (p < e) {
       t = p;
@@ -322,11 +330,17 @@ mrb_str_lines(mrb_state *mrb, mrb_value self)
       len = (mrb_int) (p - t);
       arg = mrb_str_new(mrb, t, len);
       mrb_yield_argv(mrb, blk, 1, &arg);
+      mrb_gc_arena_restore(mrb, ai);
+      if (b != RSTRING_PTR(self)) {
+        ptrdiff_t diff = p - b;
+        b = RSTRING_PTR(self);
+        p = b + diff;
+      }
+      e = b + RSTRING_LEN(self);
     }
     return self;
   }
   while (p < e) {
-    ai = mrb_gc_arena_save(mrb);
     t = p;
     while (p < e && *p != '\n') p++;
     if (*p == '\n') p++;
@@ -429,44 +443,6 @@ mrb_str_succ(mrb_state *mrb, mrb_value self)
   return str;
 }
 
-/*
- *  call-seq:
- *     str.prepend(other_str)  -> str
- *
- *  Prepend---Prepend the given string to <i>str</i>.
- *
- *     a = "world"
- *     a.prepend("hello ") #=> "hello world"
- *     a                   #=> "hello world"
- */
-static mrb_value
-mrb_str_prepend(mrb_state *mrb, mrb_value self)
-{
-  struct RString *s1 = mrb_str_ptr(self), *s2, *temp_s;
-  mrb_int len;
-  mrb_value other, temp_str;
-
-  mrb_get_args(mrb, "S", &other);
-
-  mrb_str_modify(mrb, s1);
-  if (!mrb_string_p(other)) {
-    other = mrb_str_to_str(mrb, other);
-  }
-  s2 = mrb_str_ptr(other);
-  len = RSTR_LEN(s1) + RSTR_LEN(s2);
-  temp_str = mrb_str_new(mrb, NULL, RSTR_LEN(s1));
-  temp_s = mrb_str_ptr(temp_str);
-  memcpy(RSTR_PTR(temp_s), RSTR_PTR(s1), RSTR_LEN(s1));
-  if (RSTRING_CAPA(self) < len) {
-    mrb_str_resize(mrb, self, len);
-  }
-  memcpy(RSTR_PTR(s1), RSTR_PTR(s2), RSTR_LEN(s2));
-  memcpy(RSTR_PTR(s1) + RSTR_LEN(s2), RSTR_PTR(temp_s), RSTR_LEN(temp_s));
-  RSTR_SET_LEN(s1, len);
-  RSTR_PTR(s1)[len] = '\0';
-  return self;
-}
-
 #ifdef MRB_UTF8_STRING
 static const char utf8len_codepage_zero[256] =
 {
@@ -554,7 +530,6 @@ mrb_mruby_string_ext_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, s, "lines",           mrb_str_lines,           MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "succ",            mrb_str_succ,            MRB_ARGS_NONE());
   mrb_define_method(mrb, s, "succ!",           mrb_str_succ_bang,       MRB_ARGS_NONE());
-  mrb_define_method(mrb, s, "prepend",         mrb_str_prepend,         MRB_ARGS_REQ(1));
   mrb_alias_method(mrb, s, mrb_intern_lit(mrb, "next"), mrb_intern_lit(mrb, "succ"));
   mrb_alias_method(mrb, s, mrb_intern_lit(mrb, "next!"), mrb_intern_lit(mrb, "succ!"));
   mrb_define_method(mrb, s, "ord", mrb_str_ord, MRB_ARGS_NONE());
diff --git a/mrbgems/mruby-string-ext/test/string.rb b/mrbgems/mruby-string-ext/test/string.rb
index a5d55a7ee..24bc859d8 100644
--- a/mrbgems/mruby-string-ext/test/string.rb
+++ b/mrbgems/mruby-string-ext/test/string.rb
@@ -30,6 +30,18 @@ assert('String#setbyte') do
   assert_equal("Hello", str1)
 end
 
+assert("String#setbyte raises IndexError if arg conversion resizes String") do
+  $s = "01234\n"
+  class Tmp
+      def to_i
+          $s.chomp! ''
+          95
+      end
+  end
+  tmp = Tmp.new
+  assert_raise(IndexError) { $s.setbyte(5, tmp) }
+end
+
 assert('String#byteslice') do
   str1 = "hello"
   assert_equal("e", str1.byteslice(1))
@@ -421,6 +433,7 @@ end
 assert('String#ljust') do
   assert_equal "hello", "hello".ljust(4)
   assert_equal "hello               ", "hello".ljust(20)
+  assert_equal 20, "hello".ljust(20).length
   assert_equal "hello123412341234123", "hello".ljust(20, '1234')
   assert_equal "hello", "hello".ljust(-3)
 end
@@ -428,10 +441,55 @@ end
 assert('String#rjust') do
   assert_equal "hello", "hello".rjust(4)
   assert_equal "               hello", "hello".rjust(20)
+  assert_equal 20, "hello".rjust(20).length
   assert_equal "123412341234123hello", "hello".rjust(20, '1234')
   assert_equal "hello", "hello".rjust(-3)
 end
 
+if UTF8STRING
+  assert('String#ljust with UTF8') do
+    assert_equal "helloん              ", "helloん".ljust(20)
+    assert_equal "helloó                            ", "helloó".ljust(34)
+    assert_equal 34, "helloó".ljust(34).length
+    assert_equal "helloんんんんんんんんんんんんんん", "hello".ljust(19, 'ん')
+    assert_equal "helloんんんんんんんんんんんんんんん", "hello".ljust(20, 'ん')
+  end
+
+  assert('String#rjust with UTF8') do
+    assert_equal "              helloん", "helloん".rjust(20)
+    assert_equal "                            helloó", "helloó".rjust(34)
+    # assert_equal 34, "helloó".rjust(34).length
+    assert_equal "んんんんんんんんんんんんんんhello", "hello".rjust(19, 'ん')
+    assert_equal "んんんんんんんんんんんんんんんhello", "hello".rjust(20, 'ん')
+  end
+
+  assert('UTF8 byte counting') do
+    ret = '                                  '
+    ret[-6..-1] = "helloó"
+    assert_equal 34, ret.length
+  end
+end
+
+assert('String#ljust should not change string') do
+  a = "hello"
+  a.ljust(20)
+  assert_equal "hello", a
+end
+
+assert('String#rjust should not change string') do
+  a = "hello"
+  a.rjust(20)
+  assert_equal "hello", a
+end
+
+assert('String#ljust should raise on zero width padding') do
+  assert_raise(ArgumentError) { "foo".ljust(10, '') }
+end
+
+assert('String#rjust should raise on zero width padding') do
+  assert_raise(ArgumentError) { "foo".rjust(10, '') }
+end
+
 assert('String#upto') do
   a     = "aa"
   start = "aa"
diff --git a/mrbgems/mruby-struct/src/struct.c b/mrbgems/mruby-struct/src/struct.c
index 1a06e0c12..93bd1e2b2 100644
--- a/mrbgems/mruby-struct/src/struct.c
+++ b/mrbgems/mruby-struct/src/struct.c
@@ -203,7 +203,7 @@ make_struct(mrb_state *mrb, mrb_value name, mrb_value members, struct RClass * k
     }
     if (mrb_const_defined_at(mrb, mrb_obj_value(klass), id)) {
       mrb_warn(mrb, "redefining constant Struct::%S", name);
-      /* ?rb_mod_remove_const(klass, mrb_sym2name(mrb, id)); */
+      mrb_const_remove(mrb, mrb_obj_value(klass), id);
     }
     c = mrb_define_class_under(mrb, klass, RSTRING_PTR(name), klass);
   }
@@ -273,31 +273,21 @@ mrb_struct_s_def(mrb_state *mrb, mrb_value klass)
   }
   else {
     if (argc > 0) name = argv[0];
-    if (argc > 1) rest = argv[1];
-    if (mrb_array_p(rest)) {
-      if (!mrb_nil_p(name) && mrb_symbol_p(name)) {
-        /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
-        mrb_ary_unshift(mrb, rest, name);
-        name = mrb_nil_value();
-      }
-    }
-    else {
-      pargv = &argv[1];
-      argcnt = argc-1;
-      if (!mrb_nil_p(name) && mrb_symbol_p(name)) {
-        /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
-        name = mrb_nil_value();
-        pargv = &argv[0];
-        argcnt++;
-      }
-      rest = mrb_ary_new_from_values(mrb, argcnt, pargv);
+    pargv = &argv[1];
+    argcnt = argc-1;
+    if (!mrb_nil_p(name) && mrb_symbol_p(name)) {
+      /* 1stArgument:symbol -> name=nil rest=argv[0]-[n] */
+      name = mrb_nil_value();
+      pargv = &argv[0];
+      argcnt++;
     }
+    rest = mrb_ary_new_from_values(mrb, argcnt, pargv);
     for (i=0; i<RARRAY_LEN(rest); i++) {
       id = mrb_obj_to_sym(mrb, RARRAY_PTR(rest)[i]);
       mrb_ary_set(mrb, rest, i, mrb_symbol_value(id));
     }
   }
-  st = make_struct(mrb, name, rest, struct_class(mrb));
+  st = make_struct(mrb, name, rest, mrb_class_ptr(klass));
   if (!mrb_nil_p(b)) {
     mrb_yield_with_class(mrb, b, 1, &st, st, mrb_class_ptr(st));
   }
@@ -703,7 +693,7 @@ mrb_mruby_struct_gem_init(mrb_state* mrb)
   mrb_define_method(mrb, st,        "to_a",           mrb_struct_to_a,        MRB_ARGS_NONE());
   mrb_define_method(mrb, st,        "values",         mrb_struct_to_a,        MRB_ARGS_NONE());
   mrb_define_method(mrb, st,        "to_h",           mrb_struct_to_h,        MRB_ARGS_NONE());
-  mrb_define_method(mrb, st,        "values_at",      mrb_struct_values_at,   MRB_ARGS_NONE());
+  mrb_define_method(mrb, st,        "values_at",      mrb_struct_values_at,   MRB_ARGS_ANY());
 }
 
 void
diff --git a/mrbgems/mruby-struct/test/struct.rb b/mrbgems/mruby-struct/test/struct.rb
index 02ecf69e4..1c0939e7f 100644
--- a/mrbgems/mruby-struct/test/struct.rb
+++ b/mrbgems/mruby-struct/test/struct.rb
@@ -158,3 +158,42 @@ assert("Struct#dig") do
   assert_equal 1, a.dig(:purple, :red)
   assert_equal 1, a.dig(1, 0)
 end
+
+assert("Struct.new removes existing constant") do
+  skip "redefining Struct with same name cause warnings"
+  begin
+    assert_not_equal Struct.new("Test", :a), Struct.new("Test", :a, :b)
+  ensure
+    Struct.remove_const :Test
+  end
+end
+
+assert("Struct#initialize_copy requires struct to be the same type") do
+  begin
+    Struct.new("Test", :a)
+    a = Struct::Test.new("a")
+    Struct.remove_const :Test
+    Struct.new("Test", :a, :b)
+    assert_raise(TypeError) do
+      a.initialize_copy(Struct::Test.new("a", "b"))
+    end
+  ensure
+    Struct.remove_const :Test
+  end
+end
+
+assert("Struct.new does not allow array") do
+  assert_raise(TypeError) do
+    Struct.new("Test", [:a])
+  end
+end
+
+assert("Struct.new generates subclass of Struct") do
+  begin
+    original_struct = Struct
+    Struct = String
+    assert_equal original_struct, original_struct.new.superclass
+  ensure
+    Struct = original_struct
+  end
+end
diff --git a/mrbgems/mruby-test/driver.c b/mrbgems/mruby-test/driver.c
index 7cc5211f0..14e93ff33 100644
--- a/mrbgems/mruby-test/driver.c
+++ b/mrbgems/mruby-test/driver.c
@@ -94,6 +94,12 @@ mrb_init_test_driver(mrb_state *mrb, mrb_bool verbose)
   mrb_define_const(mrb, mrbtest, "FIXNUM_MIN", mrb_fixnum_value(MRB_INT_MIN));
   mrb_define_const(mrb, mrbtest, "FIXNUM_BIT", mrb_fixnum_value(MRB_INT_BIT));
 
+#ifdef MRB_USE_FLOAT
+  mrb_define_const(mrb, mrbtest, "FLOAT_TOLERANCE", mrb_float_value(mrb, 1e-6));
+#else
+  mrb_define_const(mrb, mrbtest, "FLOAT_TOLERANCE", mrb_float_value(mrb, 1e-12));
+#endif
+
   if (verbose) {
     mrb_gv_set(mrb, mrb_intern_lit(mrb, "$mrbtest_verbose"), mrb_true_value());
   }
diff --git a/mrbgems/mruby-time/src/time.c b/mrbgems/mruby-time/src/time.c
index 19ce32832..43d87e5ff 100644
--- a/mrbgems/mruby-time/src/time.c
+++ b/mrbgems/mruby-time/src/time.c
@@ -183,7 +183,7 @@ static const struct mrb_data_type mrb_time_type = { "Time", mrb_free };
 /** Updates the datetime of a mrb_time based on it's timezone and
 seconds setting. Returns self on success, NULL of failure. */
 static struct mrb_time*
-mrb_time_update_datetime(struct mrb_time *self)
+time_update_datetime(mrb_state *mrb, struct mrb_time *self)
 {
   struct tm *aid;
 
@@ -193,7 +193,11 @@ mrb_time_update_datetime(struct mrb_time *self)
   else {
     aid = localtime_r(&self->sec, &self->datetime);
   }
-  if (!aid) return NULL;
+  if (!aid) {
+    mrb_raisef(mrb, E_ARGUMENT_ERROR, "%S out of Time range", mrb_float_value(mrb, (mrb_float)self->sec));
+    /* not reached */
+    return NULL;
+  }
 #ifdef NO_GMTIME_R
   self->datetime = *aid; /* copy data */
 #endif
@@ -213,7 +217,7 @@ static struct mrb_time*
 time_alloc(mrb_state *mrb, double sec, double usec, enum mrb_timezone timezone)
 {
   struct mrb_time *tm;
-  time_t tsec;
+  time_t tsec = 0;
 
   if (sizeof(time_t) == 4 && (sec > (double)INT32_MAX || (double)INT32_MIN > sec)) {
     goto out_of_range;
@@ -238,7 +242,7 @@ time_alloc(mrb_state *mrb, double sec, double usec, enum mrb_timezone timezone)
     tm->usec -= 1000000;
   }
   tm->timezone = timezone;
-  mrb_time_update_datetime(tm);
+  time_update_datetime(mrb, tm);
 
   return tm;
 }
@@ -290,7 +294,7 @@ current_mrb_time(mrb_state *mrb)
   }
 #endif
   tm->timezone = MRB_TIMEZONE_LOCAL;
-  mrb_time_update_datetime(tm);
+  time_update_datetime(mrb, tm);
 
   return tm;
 }
@@ -328,6 +332,15 @@ time_mktime(mrb_state *mrb, mrb_int ayear, mrb_int amonth, mrb_int aday,
   nowtime.tm_min   = (int)amin;
   nowtime.tm_sec   = (int)asec;
   nowtime.tm_isdst = -1;
+
+  if (nowtime.tm_mon  < 0 || nowtime.tm_mon  > 11
+      || nowtime.tm_mday < 1 || nowtime.tm_mday > 31
+      || nowtime.tm_hour < 0 || nowtime.tm_hour > 24
+      || (nowtime.tm_hour == 24 && (nowtime.tm_min > 0 || nowtime.tm_sec > 0))
+      || nowtime.tm_min  < 0 || nowtime.tm_min  > 59
+      || nowtime.tm_sec  < 0 || nowtime.tm_sec  > 60)
+    mrb_raise(mrb, E_RUNTIME_ERROR, "argument out of range");
+
   if (timezone == MRB_TIMEZONE_UTC) {
     nowsecs = timegm(&nowtime);
   }
@@ -368,6 +381,17 @@ mrb_time_local(mrb_state *mrb, mrb_value self)
           time_mktime(mrb, ayear, amonth, aday, ahour, amin, asec, ausec, MRB_TIMEZONE_LOCAL));
 }
 
+static struct mrb_time*
+time_get_ptr(mrb_state *mrb, mrb_value time)
+{
+  struct mrb_time *tm;
+
+  tm = DATA_GET_PTR(mrb, time, &mrb_time_type, struct mrb_time);
+  if (!tm) {
+    mrb_raise(mrb, E_ARGUMENT_ERROR, "uninitialized time");
+  }
+  return tm;
+}
 
 static mrb_value
 mrb_time_eq(mrb_state *mrb, mrb_value self)
@@ -377,7 +401,7 @@ mrb_time_eq(mrb_state *mrb, mrb_value self)
   mrb_bool eq_p;
 
   mrb_get_args(mrb, "o", &other);
-  tm1 = DATA_CHECK_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm1 = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
   tm2 = DATA_CHECK_GET_PTR(mrb, other, &mrb_time_type, struct mrb_time);
   eq_p = tm1 && tm2 && tm1->sec == tm2->sec && tm1->usec == tm2->usec;
 
@@ -391,7 +415,7 @@ mrb_time_cmp(mrb_state *mrb, mrb_value self)
   struct mrb_time *tm1, *tm2;
 
   mrb_get_args(mrb, "o", &other);
-  tm1 = DATA_CHECK_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm1 = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
   tm2 = DATA_CHECK_GET_PTR(mrb, other, &mrb_time_type, struct mrb_time);
   if (!tm1 || !tm2) return mrb_nil_value();
   if (tm1->sec > tm2->sec) {
@@ -417,7 +441,7 @@ mrb_time_plus(mrb_state *mrb, mrb_value self)
   struct mrb_time *tm;
 
   mrb_get_args(mrb, "f", &f);
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_time_make(mrb, mrb_obj_class(mrb, self), (double)tm->sec+f, (double)tm->usec, tm->timezone);
 }
 
@@ -429,8 +453,7 @@ mrb_time_minus(mrb_state *mrb, mrb_value self)
   struct mrb_time *tm, *tm2;
 
   mrb_get_args(mrb, "o", &other);
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
-
+  tm = time_get_ptr(mrb, self);
   tm2 = DATA_CHECK_GET_PTR(mrb, other, &mrb_time_type, struct mrb_time);
   if (tm2) {
     f = (mrb_float)(tm->sec - tm2->sec)
@@ -450,7 +473,7 @@ mrb_time_wday(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_wday);
 }
 
@@ -461,7 +484,7 @@ mrb_time_yday(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_yday + 1);
 }
 
@@ -472,7 +495,7 @@ mrb_time_year(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_year + 1900);
 }
 
@@ -483,7 +506,7 @@ mrb_time_zone(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   if (tm->timezone <= MRB_TIMEZONE_NONE) return mrb_nil_value();
   if (tm->timezone >= MRB_TIMEZONE_LAST) return mrb_nil_value();
   return mrb_str_new_static(mrb,
@@ -501,7 +524,7 @@ mrb_time_asctime(mrb_state *mrb, mrb_value self)
   char buf[256];
   int len;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   d = &tm->datetime;
   len = snprintf(buf, sizeof(buf), "%s %s %02d %02d:%02d:%02d %s%d",
     wday_names[d->tm_wday], mon_names[d->tm_mon], d->tm_mday,
@@ -518,8 +541,7 @@ mrb_time_day(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
-  if (!tm) return mrb_nil_value();
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_mday);
 }
 
@@ -531,7 +553,7 @@ mrb_time_dst_p(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_bool_value(tm->datetime.tm_isdst);
 }
 
@@ -543,11 +565,11 @@ mrb_time_getutc(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm, *tm2;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   tm2 = (struct mrb_time *)mrb_malloc(mrb, sizeof(*tm));
   *tm2 = *tm;
   tm2->timezone = MRB_TIMEZONE_UTC;
-  mrb_time_update_datetime(tm2);
+  time_update_datetime(mrb, tm2);
   return mrb_time_wrap(mrb, mrb_obj_class(mrb, self), tm2);
 }
 
@@ -558,11 +580,11 @@ mrb_time_getlocal(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm, *tm2;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   tm2 = (struct mrb_time *)mrb_malloc(mrb, sizeof(*tm));
   *tm2 = *tm;
   tm2->timezone = MRB_TIMEZONE_LOCAL;
-  mrb_time_update_datetime(tm2);
+  time_update_datetime(mrb, tm2);
   return mrb_time_wrap(mrb, mrb_obj_class(mrb, self), tm2);
 }
 
@@ -573,7 +595,7 @@ mrb_time_hour(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_hour);
 }
 
@@ -587,14 +609,14 @@ mrb_time_initialize(mrb_state *mrb, mrb_value self)
   int n;
   struct mrb_time *tm;
 
+  n = mrb_get_args(mrb, "|iiiiiii",
+       &ayear, &amonth, &aday, &ahour, &amin, &asec, &ausec);
   tm = (struct mrb_time*)DATA_PTR(self);
   if (tm) {
     mrb_free(mrb, tm);
   }
   mrb_data_init(self, NULL, &mrb_time_type);
 
-  n = mrb_get_args(mrb, "|iiiiiii",
-       &ayear, &amonth, &aday, &ahour, &amin, &asec, &ausec);
   if (n == 0) {
     tm = current_mrb_time(mrb);
   }
@@ -611,16 +633,23 @@ static mrb_value
 mrb_time_initialize_copy(mrb_state *mrb, mrb_value copy)
 {
   mrb_value src;
+  struct mrb_time *t1, *t2;
 
   mrb_get_args(mrb, "o", &src);
   if (mrb_obj_equal(mrb, copy, src)) return copy;
   if (!mrb_obj_is_instance_of(mrb, src, mrb_obj_class(mrb, copy))) {
     mrb_raise(mrb, E_TYPE_ERROR, "wrong argument class");
   }
-  if (!DATA_PTR(copy)) {
-    mrb_data_init(copy, mrb_malloc(mrb, sizeof(struct mrb_time)), &mrb_time_type);
+  t1 = (struct mrb_time *)DATA_PTR(copy);
+  t2 = (struct mrb_time *)DATA_PTR(src);
+  if (!t2) {
+    mrb_raise(mrb, E_ARGUMENT_ERROR, "uninitialized time");
+  }
+  if (!t1) {
+    t1 = (struct mrb_time *)mrb_malloc(mrb, sizeof(struct mrb_time));
+    mrb_data_init(copy, t1, &mrb_time_type);
   }
-  *(struct mrb_time *)DATA_PTR(copy) = *(struct mrb_time *)DATA_PTR(src);
+  *t1 = *t2;
   return copy;
 }
 
@@ -631,9 +660,9 @@ mrb_time_localtime(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   tm->timezone = MRB_TIMEZONE_LOCAL;
-  mrb_time_update_datetime(tm);
+  time_update_datetime(mrb, tm);
   return self;
 }
 
@@ -644,7 +673,7 @@ mrb_time_mday(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_mday);
 }
 
@@ -655,7 +684,7 @@ mrb_time_min(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_min);
 }
 
@@ -666,7 +695,7 @@ mrb_time_mon(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_mon + 1);
 }
 
@@ -677,7 +706,7 @@ mrb_time_sec(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_fixnum_value(tm->datetime.tm_sec);
 }
 
@@ -689,7 +718,7 @@ mrb_time_to_f(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_float_value(mrb, (mrb_float)tm->sec + (mrb_float)tm->usec/1.0e6);
 }
 
@@ -700,7 +729,7 @@ mrb_time_to_i(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   if (tm->sec > MRB_INT_MAX || tm->sec < MRB_INT_MIN) {
     return mrb_float_value(mrb, (mrb_float)tm->sec);
   }
@@ -714,7 +743,7 @@ mrb_time_usec(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   if (tm->usec > MRB_INT_MAX || tm->usec < MRB_INT_MIN) {
     return mrb_float_value(mrb, (mrb_float)tm->usec);
   }
@@ -728,9 +757,9 @@ mrb_time_utc(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   tm->timezone = MRB_TIMEZONE_UTC;
-  mrb_time_update_datetime(tm);
+  time_update_datetime(mrb, tm);
   return self;
 }
 
@@ -741,7 +770,7 @@ mrb_time_utc_p(mrb_state *mrb, mrb_value self)
 {
   struct mrb_time *tm;
 
-  tm = DATA_GET_PTR(mrb, self, &mrb_time_type, struct mrb_time);
+  tm = time_get_ptr(mrb, self);
   return mrb_bool_value(tm->timezone == MRB_TIMEZONE_UTC);
 }