embedded interface types in interfaces.

R=ken
OCL=25072
CL=25072

src/cmd/gc/dcl.c

@@ -643,7 +643,7 @@ funclit1(Type *type, Node *body)
 Type**
 stotype(Node *n, int et, Type **t)
 {
-	Type *f;
+	Type *f, *t1;
 	Iter save;
 	String *note;
 	int lno;
@@ -666,20 +666,50 @@ loop:
 		goto next;
 	}
 
-	if(n->op != ODCLFIELD || n->type == T)
+	if(n->op != ODCLFIELD)
 		fatal("stotype: oops %N\n", n);
 
+	if(n->type == T) {
+		// assume error already printed
+		goto next;
+	}
+
 	switch(n->val.ctype) {
 	case CTSTR:
+		if(et != TSTRUCT)
+			yyerror("interface method cannot have annotation");
 		note = n->val.u.sval;
 		break;
 	default:
-		yyerror("field annotation must be string");
+		if(et != TSTRUCT)
+			yyerror("interface method cannot have annotation");
+		else
+			yyerror("field annotation must be string");
 	case CTxxx:
 		note = nil;
 		break;
 	}
 
+	if(et == TINTER && n->left == N) {
+		// embedded interface - inline the methods
+		if(n->type->etype != TINTER) {
+			yyerror("interface contains embedded non-interface %T", t);
+			goto next;
+		}
+		for(t1=n->type->type; t1!=T; t1=t1->down) {
+			if(strcmp(t1->sym->package, package) != 0)
+				yyerror("embedded interface contains unexported method %S", t1->sym);
+			f = typ(TFIELD);
+			f->type = t1->type;
+			f->width = BADWIDTH;
+			f->nname = newname(t1->sym);
+			f->sym = t1->sym;
+			*t = f;
+			t = &f->down;
+		}
+		goto next;
+	}
+
 	f = typ(TFIELD);
 	f->type = n->type;
 	f->note = note;

src/cmd/gc/go.y

@@ -57,7 +57,7 @@
 %type	<node>		exprsym3_list_r exprsym3
 %type	<node>		name onew_name new_name new_name_list_r new_field
 %type	<node>		vardcl_list_r vardcl Avardcl Bvardcl
-%type	<node>		interfacedcl_list_r interfacedcl
+%type	<node>		interfacedcl_list_r interfacedcl interfacedcl1
 %type	<node>		structdcl_list_r structdcl embed
 %type	<node>		fnres Afnres Bfnres fnliteral xfndcl fndcl fnbody
 %type	<node>		braced_keyexpr_list keyval_list_r keyval
@@ -1385,8 +1385,8 @@ embed:
 		context = nil;
 	}
 
-interfacedcl:
-	new_name ',' interfacedcl
+interfacedcl1:
+	new_name ',' interfacedcl1
 	{
 		$$ = nod(ODCLFIELD, $1, N);
 		$$ = nod(OLIST, $$, $3);
@@ -1397,6 +1397,14 @@ interfacedcl:
 		$$->type = $2;
 	}
 
+interfacedcl:
+	interfacedcl1
+|	latype
+	{
+		$$ = nod(ODCLFIELD, N, N);
+		$$->type = oldtype($1);
+	}
+
 indcl:
 	'(' oarg_type_list ')' fnres
 	{