fix method function type compare bug (again)

R=ken
OCL=17819
CL=17819

src/cmd/gc/dcl.c

@@ -279,8 +279,10 @@ addmethod(Node *n, Type *t, int local)
 			d = f;
 			continue;
 		}
-		if(!eqtype(t, f->type, 0))
+		if(!eqtype(t, f->type, 0)) {
 			yyerror("method redeclared: %S of type %S", sf, st);
+			print("\t%T\n\t%T\n", f->type, t);
+		}
 		return;
 	}
 
@@ -337,10 +339,13 @@ funchdr(Node *n)
 	// check for same types
 	if(on != N) {
 		if(eqtype(n->type, on->type, 0)) {
-			if(!eqargs(n->type, on->type))
-				yyerror("forward declarations not the same: %S", s);
+			if(!eqargs(n->type, on->type)) {
+				yyerror("function arg names changed: %S", s);
+				print("\t%T\n\t%T\n", on->type, n->type);
+			}
 		} else {
-			yyerror("redeclare of function: %S", s);
+			yyerror("function redeclared: %S", s);
+			print("\t%T\n\t%T\n", on->type, n->type);
 			on = N;
 		}
 	}
@@ -674,7 +679,7 @@ addvar(Node *n, Type *t, int ctxt)
 	if(s->vblock == block) {
 		if(s->oname != N) {
 			yyerror("var %S redeclared in this block"
-				"\n     previous declaration at %L",
+				"\n\tprevious declaration at %L",
 				s, s->oname->lineno);
 		} else
 			yyerror("var %S redeclared in this block", s);

src/cmd/gc/subr.c

@@ -1763,9 +1763,11 @@ eqtype(Type *t1, Type *t2, int d)
 		return 1;
 
 	case TFUNC:
+		// Loop over structs: receiver, in, out.
 		t1 = t1->type;
 		t2 = t2->type;
 		for(;;) {
+			Type *ta, *tb;
 			if(t1 == t2)
 				break;
 			if(t1 == T || t2 == T)
@@ -1773,8 +1775,19 @@ eqtype(Type *t1, Type *t2, int d)
 			if(t1->etype != TSTRUCT || t2->etype != TSTRUCT)
 				return 0;
 
-			if(!eqtype(t1->type, t2->type, 0))
-				return 0;
+			// Loop over fields in structs, checking type only.
+			ta = t1->type;
+			tb = t2->type;
+			while(ta != tb) {
+				if(ta == T || tb == T)
+					return 0;
+				if(ta->etype != TFIELD || tb->etype != TFIELD)
+					return 0;
+				if(!eqtype(ta->type, tb->type, 0))
+					return 0;
+				ta = ta->down;
+				tb = tb->down;
+			}
 
 			t1 = t1->down;
 			t2 = t2->down;

test/golden.out

@@ -182,9 +182,9 @@ fixedbugs/bug029.go:6: syntax error near int
 
 =========== fixedbugs/bug035.go
 fixedbugs/bug035.go:6: var i redeclared in this block
-     previous declaration at fixedbugs/bug035.go:5
+	previous declaration at fixedbugs/bug035.go:5
 fixedbugs/bug035.go:7: var f redeclared in this block
-     previous declaration at fixedbugs/bug035.go:5
+	previous declaration at fixedbugs/bug035.go:5
 
 =========== fixedbugs/bug037.go
 fixedbugs/bug037.go:6: vlong: undefined
@@ -193,7 +193,7 @@ fixedbugs/bug037.go:6: illegal types for operand: AS
 
 =========== fixedbugs/bug039.go
 fixedbugs/bug039.go:6: var x redeclared in this block
-     previous declaration at fixedbugs/bug039.go:5
+	previous declaration at fixedbugs/bug039.go:5
 
 =========== fixedbugs/bug049.go
 fixedbugs/bug049.go:6: illegal conversion of nil to string

test/method1.go

+// errchk $G $D/$F.go
+
+// 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.
+
+package main
+
+type T struct { }
+func (t *T) M(int, string);
+func (t *T) M(int, float) { }   // ERROR "redeclared"
+
+func f(int, string);
+func f(int, float) { }  // ERROR "redeclared"
+
+func g(a int, b string);
+func g(a int, c string);  // ERROR "names changed"
+