From 290e68b9833da723cbe9138856f7d6d494e5b07b Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Fri, 20 Jan 2012 17:14:09 -0500
Subject: [PATCH] gc: undo most of 'fix infinite recursion for embedded
 interfaces'

Preserve test.

changeset:   11593:f1deaf35e1d1
user:        Luuk van Dijk <lvd@golang.org>
date:        Tue Jan 17 10:00:57 2012 +0100
summary:     gc: fix infinite recursion for embedded interfaces

This is causing 'interface type loop' errors during compilation
of a complex program.  I don't understand what's happening
well enough to boil it down to a simple test case, but undoing
this change fixes the problem.

The change being undone is fixing a corner case (uses of
pointer to interface in an interface definition) that basically
only comes up in erroneous Go programs.  Let's not try to
fix this again until after Go 1.

Unfixes issue 1909.

TBR=lvd
CC=golang-dev
https://golang.org/cl/5555063
---
 src/cmd/gc/dcl.c                   |  9 +--------
 src/cmd/gc/export.c                |  9 +--------
 src/cmd/gc/fmt.c                   |  8 +-------
 test/{fixedbugs => bugs}/bug395.go | 15 +++++++++++----
 test/golden.out                    |  3 +++
 5 files changed, 17 insertions(+), 27 deletions(-)
 rename test/{fixedbugs => bugs}/bug395.go (63%)

diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 94258a0c593..66edab9b94b 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -940,19 +940,13 @@ interfacefield(Node *n)
 Type*
 tointerface(NodeList *l)
 {
-	Type *t, *f, **tp, **otp, *t1;
+	Type *t, *f, **tp, *t1;
 
 	t = typ(TINTER);
-	t->orig = typ(TINTER);
 
 	tp = &t->type;
-	otp = &t->orig->type;
-
 	for(; l; l=l->next) {
 		f = interfacefield(l->n);
-		*otp = typ(TFIELD);
-		**otp = *f;
-		otp = &(*otp)->down;
 
 		if (l->n->left == N && f->type->etype == TINTER) {
 			// embedded interface, inline methods
@@ -961,7 +955,6 @@ tointerface(NodeList *l)
 				f->type = t1->type;
 				f->broke = t1->broke;
 				f->sym = t1->sym;
-				f->embedded = 1;
 				if(f->sym)
 					f->nname = newname(f->sym);
 				*tp = f;
diff --git a/src/cmd/gc/export.c b/src/cmd/gc/export.c
index 965b745a802..05fdcbf32b8 100644
--- a/src/cmd/gc/export.c
+++ b/src/cmd/gc/export.c
@@ -241,13 +241,6 @@ dumpexporttype(Type *t)
 	if(t->sym != S && t->etype != TFIELD)
 		dumppkg(t->sym->pkg);
 
-	// fmt will print the ->orig of an interface, which has the original embedded interfaces.
-	// be sure to dump them here
-	if(t->etype == TINTER)
-		for(f=t->orig->type; f; f=f->down)
-			if(f->sym == S)
-				dumpexporttype(f->type);
-
 	dumpexporttype(t->type);
 	dumpexporttype(t->down);
 
@@ -477,7 +470,7 @@ importtype(Type *pt, Type *t)
 		pt->sym->lastlineno = parserline();
 		declare(n, PEXTERN);
 		checkwidth(pt);
-	} else if(!eqtype(pt->orig, t->orig))
+	} else if(!eqtype(pt->orig, t))
 		yyerror("inconsistent definition for type %S during import\n\t%lT\n\t%lT", pt->sym, pt, t);
 
 	if(debug['E'])
diff --git a/src/cmd/gc/fmt.c b/src/cmd/gc/fmt.c
index 6f2041c1c56..b7a648789ab 100644
--- a/src/cmd/gc/fmt.c
+++ b/src/cmd/gc/fmt.c
@@ -640,15 +640,9 @@ typefmt(Fmt *fp, Type *t)
 		return fmtprint(fp, "map[%T]%T", t->down, t->type);
 
 	case TINTER:
-		t = t->orig;
 		fmtstrcpy(fp, "interface {");
 		for(t1=t->type; t1!=T; t1=t1->down)
-			if(!t1->sym) {
-				if(t1->down)
-					fmtprint(fp, " %T;", t1->type);
-				else
-					fmtprint(fp, " %T ", t1->type);
-			} else if(exportname(t1->sym->name)) {
+			if(exportname(t1->sym->name)) {
 				if(t1->down)
 					fmtprint(fp, " %hS%hT;", t1->sym, t1->type);
 				else
diff --git a/test/fixedbugs/bug395.go b/test/bugs/bug395.go
similarity index 63%
rename from test/fixedbugs/bug395.go
rename to test/bugs/bug395.go
index d0af3f9fce1..adf74497cde 100644
--- a/test/fixedbugs/bug395.go
+++ b/test/bugs/bug395.go
@@ -1,4 +1,5 @@
-// $G $D/$F.go || echo "Bug395"
+// echo bug395 is broken  # takes 90+ seconds to break
+// # $G $D/$F.go || echo bug395
 
 // Copyright 2011 The Go Authors.  All rights reserved.
 // Use of this source code is governed by a BSD-style
@@ -9,7 +10,13 @@
 package test
 
 type Foo interface {
-       Bar() interface{Foo}
-       Baz() interface{Foo}
-       Bug() interface{Foo}
+	Bar() interface {
+		Foo
+	}
+	Baz() interface {
+		Foo
+	}
+	Bug() interface {
+		Foo
+	}
 }
diff --git a/test/golden.out b/test/golden.out
index d7ecbdc8783..e0b4cf6e2a7 100644
--- a/test/golden.out
+++ b/test/golden.out
@@ -14,3 +14,6 @@
 == fixedbugs/
 
 == bugs/
+
+=========== bugs/bug395.go
+bug395 is broken