From 573374c476611d26a3422497bebb46a5a63ff7ba Mon Sep 17 00:00:00 2001
From: David Symonds <dsymonds@golang.org>
Date: Tue, 30 Jul 2013 13:15:31 +1000
Subject: [PATCH] cmd/vet: Fix handling of non-Stringer arguments.

First, %v and %T accept any arguments, so they should never warn.
Second, pointer types were not handled in matchArgType.
Third, the default response for matchArgType should be false.

R=r
CC=adonovan, golang-dev
https://golang.org/cl/12038050
---
 cmd/vet/testdata/print.go |  8 ++++++++
 cmd/vet/types.go          | 10 +++++++---
 2 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/cmd/vet/testdata/print.go b/cmd/vet/testdata/print.go
index 7a1b6714cf..f41e7543c5 100644
--- a/cmd/vet/testdata/print.go
+++ b/cmd/vet/testdata/print.go
@@ -80,6 +80,8 @@ func PrintfTests() {
 	fmt.Printf("%.*s %d %g", 3, "hi", 23, 2.3)
 	fmt.Printf("%s", &stringerv)
 	fmt.Printf("%T", &stringerv)
+	fmt.Printf("%v", notstringerv)
+	fmt.Printf("%T", notstringerv)
 	fmt.Printf("%*%", 2) // Ridiculous but allowed.
 
 	fmt.Printf("%g", 1+2i)
@@ -107,6 +109,8 @@ func PrintfTests() {
 	fmt.Printf("%X", 2.3)                      // ERROR "arg 2.3 for printf verb %X of wrong type"
 	fmt.Printf("%s", stringerv)                // ERROR "arg stringerv for printf verb %s of wrong type"
 	fmt.Printf("%t", stringerv)                // ERROR "arg stringerv for printf verb %t of wrong type"
+	fmt.Printf("%q", notstringerv)             // ERROR "arg notstringerv for printf verb %q of wrong type"
+	fmt.Printf("%t", notstringerv)             // ERROR "arg notstringerv for printf verb %t of wrong type"
 	fmt.Printf("%.*s %d %g", 3, "hi", 23, 'x') // ERROR "arg 'x' for printf verb %g of wrong type"
 	fmt.Println()                              // not an error
 	fmt.Println("%s", "hi")                    // ERROR "possible formatting directive in Println call"
@@ -198,3 +202,7 @@ func (*stringer) Warn(int, ...interface{}) string {
 func (*stringer) Warnf(int, string, ...interface{}) string {
 	return "warnf"
 }
+
+type notstringer struct{}
+
+var notstringerv notstringer
diff --git a/cmd/vet/types.go b/cmd/vet/types.go
index 27ce46879f..bd43f955cd 100644
--- a/cmd/vet/types.go
+++ b/cmd/vet/types.go
@@ -75,6 +75,10 @@ var (
 // may be printed with %d etc. if that is appropriate for their element
 // types.)
 func (f *File) matchArgType(t printfArgType, typ types.Type, arg ast.Expr) bool {
+	// %v, %T accept any argument type.
+	if t == anyType {
+		return true
+	}
 	if typ == nil {
 		// external call
 		typ = f.pkg.types[arg]
@@ -108,6 +112,9 @@ func (f *File) matchArgType(t printfArgType, typ types.Type, arg ast.Expr) bool
 		// Recurse: []int matches %d.
 		return t&argPointer != 0 || f.matchArgType(t, typ.Elem(), arg)
 
+	case *types.Pointer:
+		return t&argPointer != 0
+
 	case *types.Basic:
 		switch typ.Kind() {
 		case types.UntypedBool,
@@ -158,9 +165,6 @@ func (f *File) matchArgType(t printfArgType, typ types.Type, arg ast.Expr) bool
 			return true // Probably a type check problem.
 		}
 		panic("unreachable")
-
-	default:
-		return true
 	}
 
 	return false