cmd/vet: fix printf test for unsafe Pointer

And fix test. Pointer to unsafe.Pointer tests nothing important...
Also identify the incorrect type: go/types.Type is a Stringer.

Also fix a couple of incorrect format verbs found by new printf checker,
now that we can run it on more files.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/7385051

src/cmd/vet/print.go

@@ -276,6 +276,9 @@ func (f *File) checkPrintfArg(call *ast.CallExpr, verb rune, flags []byte, argNu
 					return
 				}
 			}
+			if f.pkg == nil { // Nothing more to do.
+				return
+			}
 			// Verb is good. If nargs>1, we have something like %.*s and all but the final
 			// arg must be integer.
 			for i := 0; i < nargs-1; i++ {
@@ -285,8 +288,13 @@ func (f *File) checkPrintfArg(call *ast.CallExpr, verb rune, flags []byte, argNu
 			}
 			for _, v := range printVerbs {
 				if v.verb == verb {
-					if !f.matchArgType(v.typ, call.Args[argNum+nargs-1]) {
-						f.Badf(call.Pos(), "arg for printf verb %%%c of wrong type", verb)
+					arg := call.Args[argNum+nargs-1]
+					if !f.matchArgType(v.typ, arg) {
+						typeString := ""
+						if typ := f.pkg.types[arg]; typ != nil {
+							typeString = typ.String()
+						}
+						f.Badf(call.Pos(), "arg for printf verb %%%c of wrong type: %s", verb, typeString)
 					}
 					break
 				}
@@ -298,9 +306,6 @@ func (f *File) checkPrintfArg(call *ast.CallExpr, verb rune, flags []byte, argNu
 }
 
 func (f *File) matchArgType(t printfArgType, arg ast.Expr) bool {
-	if f.pkg == nil {
-		return true // Don't know; assume OK.
-	}
 	// TODO: for now, we can only test builtin types and untyped constants.
 	typ := f.pkg.types[arg]
 	if typ == nil {
@@ -322,7 +327,7 @@ func (f *File) matchArgType(t printfArgType, arg ast.Expr) bool {
 	case types.String:
 		return t&argString != 0
 	case types.UnsafePointer:
-		return t&argPointer != 0
+		return t&(argPointer|argInt) != 0
 	case types.UntypedBool:
 		return t&argBool != 0
 	case types.UntypedComplex:

src/cmd/vet/test_print.go

@@ -14,8 +14,8 @@ import (
 )
 
 func UnsafePointerPrintfTest() {
-	var up *unsafe.Pointer
-	fmt.Printf("%p", up)
+	var up unsafe.Pointer
+	fmt.Printf("%p, %x %X", up, up, up)
 }
 
 // Error methods that do not satisfy the Error interface and should be checked.

src/pkg/sync/atomic/atomic_test.go

@@ -1119,7 +1119,7 @@ func TestStoreLoadRelAcq32(t *testing.T) {
 					d1 := X.data1
 					d2 := X.data2
 					if d1 != i || d2 != float32(i) {
-						t.Fatalf("incorrect data: %d/%d (%d)", d1, d2, i)
+						t.Fatalf("incorrect data: %d/%g (%d)", d1, d2, i)
 					}
 				}
 			}
@@ -1167,7 +1167,7 @@ func TestStoreLoadRelAcq64(t *testing.T) {
 					d1 := X.data1
 					d2 := X.data2
 					if d1 != i || d2 != float64(i) {
-						t.Fatalf("incorrect data: %d/%d (%d)", d1, d2, i)
+						t.Fatalf("incorrect data: %d/%g (%d)", d1, d2, i)
 					}
 				}
 			}