From 6c2738eb43e7cc3ea828c7b7401bef27cc5dd9c9 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Fri, 7 Aug 2009 13:14:01 -0700
Subject: [PATCH] bug181 - type T *struct { T } is an invalid embedded type

R=ken
OCL=32886
CL=32886
---
 src/cmd/gc/dcl.c         |  4 +++-
 src/cmd/gc/go.h          |  1 +
 src/cmd/gc/walk.c        |  8 +++++++-
 test/fixedbugs/bug181.go | 11 +++++++++++
 4 files changed, 22 insertions(+), 2 deletions(-)
 create mode 100644 test/fixedbugs/bug181.go

diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 1768f2e121f..fe64ee08d7a 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -900,8 +900,10 @@ stotype(NodeList *l, int et, Type **t)
 				t1 = n->type;
 				if(t1->sym == S && isptr[t1->etype])
 					t1 = t1->type;
-				if(t1 != T && isptr[t1->etype])
+				if(isptr[t1->etype])
 					yyerror("embedded type cannot be a pointer");
+				else if(t1->etype == TFORW && t1->embedlineno == 0)
+					t1->embedlineno = lineno;
 			}
 		}
 
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index 3c11d038a0b..3ddeca1dffc 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -175,6 +175,7 @@ struct	Type
 	int32	bound;		// negative is dynamic array
 
 	int32	maplineno;	// first use of TFORW as map key
+	int32	embedlineno;	// first use of TFORW as embedded type
 };
 #define	T	((Type*)0)
 
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 044a29643b9..2298c659cba 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -111,7 +111,7 @@ walkdeflist(NodeList *l)
 void
 walkdef(Node *n)
 {
-	int lno, maplineno;
+	int lno, maplineno, embedlineno;
 	NodeList *init;
 	Node *e;
 	Type *t;
@@ -210,6 +210,7 @@ walkdef(Node *n)
 		// copy new type and clear fields
 		// that don't come along
 		maplineno = n->type->maplineno;
+		embedlineno = n->type->embedlineno;
 		*n->type = *t;
 		t = n->type;
 		t->sym = n->sym;
@@ -226,6 +227,11 @@ walkdef(Node *n)
 			lineno = maplineno;
 			maptype(n->type, types[TBOOL]);
 		}
+		if(embedlineno) {
+			lineno = embedlineno;
+			if(isptr[t->etype])
+				yyerror("embedded type cannot be a pointer");
+		}
 		break;
 	}
 
diff --git a/test/fixedbugs/bug181.go b/test/fixedbugs/bug181.go
new file mode 100644
index 00000000000..f87bc9d4ee9
--- /dev/null
+++ b/test/fixedbugs/bug181.go
@@ -0,0 +1,11 @@
+// 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 {
+	T;	// ERROR "embed.*pointer"
+}