gc: keep track of real actual type of identifiers.

R=rsc
CC=golang-dev
https://golang.org/cl/2519042

src/cmd/gc/go.h

@@ -41,7 +41,7 @@ enum
 	AMEMWORD,
 
 	BADWIDTH	= -1000000000,
-	MAXWIDTH        = 1<<30
+	MAXWIDTH	= 1<<30
 };
 
 /*
@@ -218,6 +218,7 @@ struct	Node
 	Node*	left;
 	Node*	right;
 	Type*	type;
+	Type*	realtype;	// as determined by typecheck
 	NodeList*	list;
 	NodeList*	rlist;
 
@@ -636,9 +637,9 @@ EXTERN	Label*	labellist;
  *
  * typedef	struct
  * {				// must not move anything
- * 	uchar	array[8];	// pointer to data
- * 	uchar	nel[4];		// number of elements
- * 	uchar	cap[4];		// allocated number of elements
+ *	uchar	array[8];	// pointer to data
+ *	uchar	nel[4];		// number of elements
+ *	uchar	cap[4];		// allocated number of elements
  * } Array;
  */
 EXTERN	int	Array_array;	// runtime offsetof(Array,array) - same for String
@@ -653,8 +654,8 @@ EXTERN	int	sizeof_Array;	// runtime sizeof(Array)
  *
  * typedef	struct
  * {				// must not move anything
- * 	uchar	array[8];	// pointer to data
- * 	uchar	nel[4];		// number of elements
+ *	uchar	array[8];	// pointer to data
+ *	uchar	nel[4];		// number of elements
  * } String;
  */
 EXTERN	int	sizeof_String;	// runtime sizeof(String)

src/cmd/gc/subr.c

@@ -1273,7 +1273,7 @@ Tpretty(Fmt *fp, Type *t)
 			fmtprint(fp, "...%T", t->type->type);
 		else
 			fmtprint(fp, "%T", t->type);
-		if(t->note) {	
+		if(t->note) {
 			fmtprint(fp, " ");
 			if(exporting)
 				fmtprint(fp, ":");
@@ -3607,10 +3607,11 @@ umagic(Magic *m)
 Sym*
 ngotype(Node *n)
 {
-	if(n->sym != S && strncmp(n->sym->name, "autotmp_", 8) != 0)
-	if(n->type->etype != TFUNC || n->type->thistuple == 0)
-	if(n->type->etype != TSTRUCT || n->type->funarg == 0)
-		return typename(n->type)->left->sym;
+	if(n->sym != S && n->realtype != T)
+	if(strncmp(n->sym->name, "autotmp_", 8) != 0)
+	if(strncmp(n->sym->name, "statictmp_", 8) != 0)
+		return typename(n->realtype)->left->sym;
+
 	return S;
 }
 
@@ -3684,4 +3685,3 @@ strlit(char *s)
 	t->len = strlen(s);
 	return t;
 }
-

src/cmd/gc/typecheck.c

@@ -80,7 +80,7 @@ typecheck(Node **np, int top)
 	n = *np;
 	if(n == N)
 		return N;
-	
+
 	// Resolve definition of name and value of iota lazily.
 	n = resolve(n);
 	*np = n;
@@ -112,6 +112,7 @@ typecheck(Node **np, int top)
 			goto error;
 		}
 		walkdef(n);
+		n->realtype = n->type;
 		if(n->op == ONONAME)
 			goto error;
 	}