From 25d22d9abae4345c24cd2ae7f26de1846888faa4 Mon Sep 17 00:00:00 2001
From: Emmanuel Odeke <emm.odeke@gmail.com>
Date: Sat, 10 Feb 2018 20:10:26 -0800
Subject: [PATCH] cmd/compile: report the struct type in invalid number of
 initializer values

Fixes #23732

Disambiguate "too few" or "too many" values in struct
initializer messages by reporting the name of the literal.

After:
issue23732.go:27:3: too few values in Foo literal
issue23732.go:34:12: too many values in Bar literal
issue23732.go:40:6: too few values in Foo literal
issue23732.go:40:12: too many values in Bar literal

Change-Id: Ieca37298441d907ac78ffe960c5ab55741a362ef
Reviewed-on: https://go-review.googlesource.com/93277
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>
---
 src/cmd/compile/internal/gc/typecheck.go |  4 +--
 test/fixedbugs/issue23732.go             | 42 ++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100644 test/fixedbugs/issue23732.go

diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index 5285cb22d9..0161f26890 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -3030,7 +3030,7 @@ func typecheckcomplit(n *Node) *Node {
 				ls[i] = n1
 				if i >= t.NumFields() {
 					if !errored {
-						yyerror("too many values in struct initializer")
+						yyerror("too many values in %v", n)
 						errored = true
 					}
 					continue
@@ -3048,7 +3048,7 @@ func typecheckcomplit(n *Node) *Node {
 				ls[i] = n1
 			}
 			if len(ls) < t.NumFields() {
-				yyerror("too few values in struct initializer")
+				yyerror("too few values in %v", n)
 			}
 		} else {
 			hash := make(map[string]bool)
diff --git a/test/fixedbugs/issue23732.go b/test/fixedbugs/issue23732.go
new file mode 100644
index 0000000000..be17bf4f61
--- /dev/null
+++ b/test/fixedbugs/issue23732.go
@@ -0,0 +1,42 @@
+// errorcheck
+
+// Copyright 2018 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 23732: Give better details about which struct
+// initializer has the wrong number of values.
+
+package main
+
+type Foo struct {
+	A int
+	B int
+	C interface{}
+	Bar
+}
+
+type Bar struct {
+	A string
+}
+
+func main() {
+	_ = Foo{
+		1,
+		2,
+		3, // ERROR "too few values in Foo literal"
+	}
+
+	_ = Foo{
+		1,
+		2,
+		3,
+		Bar{"A", "B"}, // ERROR "too many values in Bar literal"
+	}
+
+	_ = Foo{
+		1,
+		2,
+		Bar{"A", "B"}, // ERROR "too many values in Bar literal" "too few values in Foo literal"
+	}
+}