gc: add forgotten typecheck in a lonely corner of sinit

Fixes #2549

R=rsc
CC=golang-dev
https://golang.org/cl/5484060

src/cmd/gc/sinit.c

@@ -707,9 +707,10 @@ slicelit(int ctxt, Node *n, Node *var, NodeList **init)
 
 	// set auto to point at new temp or heap (3 assign)
 	if(n->esc == EscNone) {
-		a = temp(t);
+		a = nod(OAS, temp(t), N);
-		*init = list(*init, nod(OAS, a, N));  // zero new temp
+		typecheck(&a, Etop);
-		a = nod(OADDR, a, N);
+		*init = list(*init, a);  // zero new temp
+		a = nod(OADDR, a->left, N);
 	} else {
 		a = nod(ONEW, N, N);
 		a->list = list1(typenod(t));

test/fixedbugs/bug387.go

@@ -0,0 +1,30 @@
+// $G $D/$F.go || echo "Bug387"
+
+// Copyright 2011 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.
+
+// Issue 2549
+
+/*  Used to die with
+missing typecheck: [7f5bf07b4438]
+
+.   AS l(45)
+.   .   NAME-main.autotmp_0017 u(1) a(1) l(45) x(0+0) class(PAUTO)
+esc(N) tc(1) used(1) ARRAY-[2]string
+internal compiler error: missing typecheck 
+*/
+package main
+
+import (
+        "fmt"
+        "path/filepath"
+)
+
+func main() {
+        switch _, err := filepath.Glob(filepath.Join(".", "vnc")); {
+        case err != nil:
+                fmt.Println(err)
+        }
+}
+