From a599b4890a06486b1f888216ae87b4cbf3df418a Mon Sep 17 00:00:00 2001
From: Jan Ziak <0xe2.0x9a.0x9b@gmail.com>
Date: Fri, 11 Apr 2014 15:57:30 +0200
Subject: [PATCH] cmd/gc: increase specificity of errors in function call
 context

Fixes #7129

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/86470044
---
 src/cmd/gc/typecheck.c      |  8 ++++++--
 test/fixedbugs/issue7129.go | 21 +++++++++++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)
 create mode 100644 test/fixedbugs/issue7129.go

diff --git a/src/cmd/gc/typecheck.c b/src/cmd/gc/typecheck.c
index 2b44cd8202..7eda63bad1 100644
--- a/src/cmd/gc/typecheck.c
+++ b/src/cmd/gc/typecheck.c
@@ -310,7 +310,7 @@ typecheck1(Node **np, int top)
 	int ok, ntop;
 	Type *t, *tp, *missing, *have, *badtype;
 	Val v;
-	char *why;
+	char *why, *desc, descbuf[64];
 	
 	n = *np;
 
@@ -1139,7 +1139,11 @@ reswitch:
 			}
 			break;
 		}
-		typecheckaste(OCALL, n->left, n->isddd, getinargx(t), n->list, "function argument");
+		if(snprint(descbuf, sizeof descbuf, "argument to %N", n->left) < sizeof descbuf)
+			desc = descbuf;
+		else
+			desc = "function argument";
+		typecheckaste(OCALL, n->left, n->isddd, getinargx(t), n->list, desc);
 		ok |= Etop;
 		if(t->outtuple == 0)
 			goto ret;
diff --git a/test/fixedbugs/issue7129.go b/test/fixedbugs/issue7129.go
new file mode 100644
index 0000000000..2425cbd343
--- /dev/null
+++ b/test/fixedbugs/issue7129.go
@@ -0,0 +1,21 @@
+// errorcheck
+
+// Copyright 2014 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 7129: inconsistent "wrong arg type" error for multivalued g in f(g())
+
+package main
+
+func f(int) {}
+
+func g() bool { return true }
+
+func h(int, int) {}
+
+func main() {
+	f(g())        // ERROR "in argument to f"
+	f(true)       // ERROR "in argument to f"
+	h(true, true) // ERROR "in argument to h"
+}