From f3ecb298ad3187a6c47f43916480d396ec8c35c3 Mon Sep 17 00:00:00 2001
From: Russ Cox <rsc@golang.org>
Date: Thu, 3 Apr 2014 19:04:33 -0400
Subject: [PATCH] cmd/gc: reject builtin function calls in len(fixed array)
 constants

Fixes #7385.

LGTM=iant
R=golang-codereviews, iant
CC=golang-codereviews
https://golang.org/cl/84010044
---
 src/cmd/gc/const.c | 17 ++++++++++++++++-
 test/const5.go     |  4 ++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/cmd/gc/const.c b/src/cmd/gc/const.c
index cfd81e86f5..28d0725d33 100644
--- a/src/cmd/gc/const.c
+++ b/src/cmd/gc/const.c
@@ -1629,10 +1629,25 @@ hascallchan(Node *n)
 	if(n == N)
 		return 0;
 	switch(n->op) {
+	case OAPPEND:
 	case OCALL:
 	case OCALLFUNC:
-	case OCALLMETH:
 	case OCALLINTER:
+	case OCALLMETH:
+	case OCAP:
+	case OCLOSE:
+	case OCOMPLEX:
+	case OCOPY:
+	case ODELETE:
+	case OIMAG:
+	case OLEN:
+	case OMAKE:
+	case ONEW:
+	case OPANIC:
+	case OPRINT:
+	case OPRINTN:
+	case OREAL:
+	case ORECOVER:
 	case ORECV:
 		return 1;
 	}
diff --git a/test/const5.go b/test/const5.go
index 87fe33a385..60b4d0d12c 100644
--- a/test/const5.go
+++ b/test/const5.go
@@ -18,6 +18,7 @@ var s [][30]int
 
 func f() *[40]int
 var c chan *[50]int
+var z complex128
 
 const (
 	n1 = len(b.a)
@@ -29,5 +30,8 @@ const (
 
 	n6 = cap(f())  // ERROR "is not a constant|is not constant"
 	n7 = cap(<-c) // ERROR "is not a constant|is not constant"
+	n8 = real(z) // ERROR "is not a constant|is not constant"
+	n9 = len([4]float64{real(z)}) // ERROR "is not a constant|is not constant"
+
 )