code review 883049: gc: make sure main.main has correct type

src/cmd/gc/go.y

 // Copyright 2009 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
 /*
  * Go language grammar.
  *
  * The Go semicolon rules are:
  *
  *  1. all statements and declarations are terminated by semicolons.
@@ skipping 1052 matching lines @@
         }
 
 fndcl:
         dcl_name '(' oarg_type_list_ocomma ')' fnres
         {
                 Node *n;
 
                 $3 = checkarglist($3, 1);
                 $$ = nod(ODCLFUNC, N, N);
                 $$->nname = $1;
-                if($3 == nil && $5 == nil)
-                        $$->nname = renameinit($1);
                 n = nod(OTFUNC, N, N);
                 n->list = $3;
                 n->rlist = $5;
+                if(strcmp($1->sym->name, "init") == 0) {
+                        $$->nname = renameinit($1);
+                        if($3 != nil || $5 != nil)
+                                yyerror("func init must have no arguments and no return values");
+                }
+                if(strcmp(localpkg->name, "main") == 0 && strcmp($1->sym->name, "main") == 0) {
+                        if($3 != nil || $5 != nil)
+                                yyerror("func main must have no arguments and no return values");
+                }
                 // TODO: check if nname already has an ntype
                 $$->nname->ntype = n;
                 funchdr($$);
         }
 |       '(' oarg_type_list_ocomma ')' new_name '(' oarg_type_list_ocomma ')' fnres
         {
                 Node *rcvr, *t;
 
                 $2 = checkarglist($2, 0);
                 $6 = checkarglist($6, 1);
@@ skipping 733 matching lines @@
 
 hidden_interfacedcl_list:
         hidden_interfacedcl
         {
                 $$ = list1($1);
         }
 |       hidden_interfacedcl_list ';' hidden_interfacedcl
         {
                 $$ = list($1, $3);
         }