1 files changed, 48 insertions, 20 deletions

diff --git a/mrbgems/mruby-compiler/core/parse.y b/mrbgems/mruby-compiler/core/parse.y
index de875a1ae..f8db486a5 100644
--- a/mrbgems/mruby-compiler/core/parse.y
+++ b/mrbgems/mruby-compiler/core/parse.y
@@ -318,19 +318,19 @@ locals_node(parser_state *p)
 static void
 nvars_nest(parser_state *p)
 {
-  p->nvars = cons(p->nvars, nint(0));
+  p->nvars = cons(nint(0), p->nvars);
 }
 
 static void
 nvars_block(parser_state *p)
 {
-  p->nvars = cons(p->nvars, nint(-2));
+  p->nvars = cons(nint(-2), p->nvars);
 }
 
 static void
 nvars_unnest(parser_state *p)
 {
-  p->nvars = p->nvars->car;
+  p->nvars = p->nvars->cdr;
 }
 
 /* (:scope (vars..) (prog...)) */
@@ -671,12 +671,9 @@ new_cvar(parser_state *p, mrb_sym sym)
 static node*
 new_nvar(parser_state *p, int num)
 {
-  if (!p->nvars || intn(p->nvars->cdr) < -1) {
-    yyerror(p, "numbered parameter outside block");
-  } else {
-    int nvars = intn(p->nvars->cdr);
-    p->nvars->cdr = nint(nvars > num ? nvars : num);
-  }
+  int nvars = intn(p->nvars->car);
+
+  p->nvars->car = nint(nvars > num ? nvars : num);
   return cons((node*)NODE_NVAR, nint(num));
 }
 
@@ -840,7 +837,7 @@ new_block_arg(parser_state *p, node *a)
 static node*
 setup_numparams(parser_state *p, node *a)
 {
-  int nvars = intn(p->nvars->cdr);
+  int nvars = intn(p->nvars->car);
   if (nvars > 0) {
     int i;
     mrb_sym sym;
@@ -1955,6 +1952,10 @@ lhs             : variable
                       backref_error(p, $1);
                       $$ = 0;
                     }
+                | tNUMPARAM
+                    {
+                      yyerror(p, "can't assign to numbered parameter");
+                    }
                 ;
 
 cname           : tIDENTIFIER
@@ -3278,6 +3279,10 @@ var_lhs         : variable
                     {
                       assignable(p, $1);
                     }
+                | tNUMPARAM
+                    {
+                      yyerror(p, "can't assign to numbered parameter");
+                    }
                 ;
 
 var_ref         : variable
@@ -3538,6 +3543,11 @@ f_bad_arg       : tCONSTANT
                       yyerror(p, "formal argument cannot be a class variable");
                       $$ = 0;
                     }
+                | tNUMPARAM
+                    {
+                      yyerror(p, "formal argument cannot be a numbered parameter");
+                      $$ = 0;
+                    }
                 ;
 
 f_norm_arg      : f_bad_arg
@@ -5957,24 +5967,33 @@ parser_yylex(parser_state *p)
     case '_':
       if (toklen(p) == 2 && ISDIGIT(tok(p)[1]) && p->nvars) {
         int n = tok(p)[1] - '0';
+        int nvar;
 
         if (n > 0) {
-          node *nvars = p->nvars->car;
+          node *nvars = p->nvars->cdr;
 
           while (nvars) {
-            if (intn(nvars->cdr) > 0) {
-              yywarning(p, "numbered parameter in nested block");
+            nvar = intn(nvars->car);
+            if (nvar == -2) break; /* top of the scope */
+            if (nvar > 0) {
+              yywarning(p, "numbered parameter used in outer block");
               break;
             }
-            nvars->cdr = nint(-1);
-            nvars = nvars->car;
+            nvars->car = nint(-1);
+            nvars = nvars->cdr;
           }
-          if (intn(p->nvars->cdr) < 0) {
-            yywarning(p, "numbered parameter in nested block");
+          nvar = intn(p->nvars->car);
+          if (nvar == -1) {
+            yywarning(p, "numbered parameter used in inner block");
+          }
+          if (nvar >= -1) {
+            pylval.num = n;
+            p->lstate = EXPR_END;
+            return tNUMPARAM;
+          }
+          else {
+            yywarning(p, "identifier for numbered parameter; consider another name");
           }
-          pylval.num = n;
-          p->lstate = EXPR_END;
-          return tNUMPARAM;
         }
       }
       /* fall through */
@@ -5993,6 +6012,15 @@ parser_yylex(parser_state *p)
           else {
             pushback(p, c);
           }
+          if ((c = nextc(p)) == '=' && !peek(p, '~') && !peek(p, '>') &&
+              (!peek(p, '=') || (peek_n(p, '>', 1)))) {
+            result = tIDENTIFIER;
+            tokadd(p, c);
+            tokfix(p);
+          }
+          else {
+            pushback(p, c);
+          }
         }
         if (result == 0 && ISUPPER(tok(p)[0])) {
           result = tCONSTANT;