From 401a95aa83988cda238432af107b07bf9e79e547 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Thu, 7 May 2009 13:42:47 -0700
Subject: [PATCH] if a struct s contains an anonymous interface value with
 method m, s.m() is ok and m now shows up in s's method set for interface
 runtime.

see http://cl/28419-p2 for new test interface10.go.

R=ken
OCL=28420
CL=28423
---
 src/cmd/gc/dcl.c  | 29 +++++++++++++++++++++++++----
 src/cmd/gc/go.h   |  1 +
 src/cmd/gc/obj.c  |  4 ++--
 src/cmd/gc/subr.c | 18 +++++++++++++++++-
 src/cmd/gc/walk.c |  7 +++++--
 5 files changed, 50 insertions(+), 9 deletions(-)

diff --git a/src/cmd/gc/dcl.c b/src/cmd/gc/dcl.c
index 202f48f858b..14617fb6045 100644
--- a/src/cmd/gc/dcl.c
+++ b/src/cmd/gc/dcl.c
@@ -1075,15 +1075,36 @@ Node*
 fakethis(void)
 {
 	Node *n;
-	Type *t;
 
 	n = nod(ODCLFIELD, N, N);
-	t = dostruct(N, TSTRUCT);
-	t = ptrto(t);
-	n->type = t;
+	n->type = ptrto(typ(TSTRUCT));
 	return n;
 }
 
+/*
+ * Is this field a method on an interface?
+ * Those methods have an anonymous
+ * *struct{} as the receiver.
+ * (See fakethis above.)
+ */
+int
+isifacemethod(Type *f)
+{
+	Type *rcvr;
+	Type *t;
+
+	rcvr = getthisx(f->type)->type;
+	if(rcvr->sym != S)
+		return 0;
+	t = rcvr->type;
+	if(!isptr[t->etype])
+		return 0;
+	t = t->type;
+	if(t->sym != S || t->etype != TSTRUCT || t->type != T)
+		return 0;
+	return 1;
+}
+
 /*
  * this generates a new name that is
  * pushed down on the declaration list.
diff --git a/src/cmd/gc/go.h b/src/cmd/gc/go.h
index c8f3cbf3fe9..a7f10ced290 100644
--- a/src/cmd/gc/go.h
+++ b/src/cmd/gc/go.h
@@ -822,6 +822,7 @@ void	addvar(Node*, Type*, int);
 void	addtyp(Type*, int);
 void	addconst(Node*, Node*, int);
 Node*	fakethis(void);
+int	isifacemethod(Type*);
 Node*	newname(Sym*);
 Node*	oldname(Sym*);
 Type*	newtype(Sym*);
diff --git a/src/cmd/gc/obj.c b/src/cmd/gc/obj.c
index e55e5def8c8..ee0fd53dcdd 100644
--- a/src/cmd/gc/obj.c
+++ b/src/cmd/gc/obj.c
@@ -206,7 +206,7 @@ dumpsigt(Type *progt, Type *ifacet, Type *rcvrt, Type *methodt, Sym *s)
 
 		// get receiver type for this particular method.
 		this = getthisx(f->type)->type->type;
-		if(f->embedded != 2 && isptr[this->etype] && !isptr[progt->etype]) {
+		if(f->embedded != 2 && isptr[this->etype] && !isptr[progt->etype] && !isifacemethod(f)) {
 			// pointer receiver method but value method set.
 			// ignore.
 			if(debug['r'])
@@ -238,7 +238,7 @@ dumpsigt(Type *progt, Type *ifacet, Type *rcvrt, Type *methodt, Sym *s)
 				// but we can generate more efficient code
 				// using genembedtramp if all that is necessary
 				// is a pointer adjustment and a JMP.
-				if(f->embedded && isptr[ifacet->etype])
+				if(f->embedded && isptr[ifacet->etype] && !isifacemethod(f))
 					genembedtramp(ifacet, a);
 				else
 					genwrapper(ifacet, f, a->sym);
diff --git a/src/cmd/gc/subr.c b/src/cmd/gc/subr.c
index 65bf8543f22..7972c41d8cc 100644
--- a/src/cmd/gc/subr.c
+++ b/src/cmd/gc/subr.c
@@ -2568,6 +2568,22 @@ expand0(Type *t, int followptr)
 		u = u->type;
 	}
 
+	if(u->etype == TINTER) {
+		for(f=u->type; f!=T; f=f->down) {
+			if(!exportname(f->sym->name) && strcmp(f->sym->opackage, package) != 0)
+				continue;
+			if(f->sym->uniq)
+				continue;
+			f->sym->uniq = 1;
+			sl = mal(sizeof(*sl));
+			sl->field = f;
+			sl->link = slist;
+			sl->followptr = followptr;
+			slist = sl;
+		}
+		return;
+	}
+
 	u = methtype(t);
 	if(u != T) {
 		for(f=u->method; f!=T; f=f->down) {
@@ -2858,7 +2874,7 @@ ifaceokT2I(Type *t0, Type *iface, Type **m)
 		// if pointer receiver in method,
 		// the method does not exist for value types.
 		rcvr = getthisx(tm->type)->type->type;
-		if(isptr[rcvr->etype] && !isptr[t0->etype] && !followptr) {
+		if(isptr[rcvr->etype] && !isptr[t0->etype] && !followptr && !isifacemethod(tm)) {
 			if(debug['r'])
 				yyerror("interface pointer mismatch");
 			*m = im;
diff --git a/src/cmd/gc/walk.c b/src/cmd/gc/walk.c
index 64d2ae65d0d..efb092ab81b 100644
--- a/src/cmd/gc/walk.c
+++ b/src/cmd/gc/walk.c
@@ -192,6 +192,7 @@ implicitstar(Node **nn)
 	case TMAP:
 	case TSTRING:
 	case TARRAY:
+	case TINTER:
 		break;
 	default:
 		return;
@@ -1611,8 +1612,10 @@ lookdot(Node *n, Type *t)
 		n->right = f1->nname;		// substitute real name
 		n->xoffset = f1->width;
 		n->type = f1->type;
-		if(t->etype == TINTER)
+		if(t->etype == TINTER) {
+			implicitstar(&n->left);
 			n->op = ODOTINTER;
+		}
 		return 1;
 	}
 
@@ -1742,7 +1745,7 @@ loop:
 		if(l != N || r != T)
 			yyerror("assignment count mismatch: %d = %d",
 				listcount(*nl), structcount(*nr));
-			
+
 		return rev(nn);
 	}