fmt: %T print <nil> for nil

R=r
CC=golang-dev, rsc
https://golang.org/cl/1014043

src/pkg/fmt/fmt_test.go

@@ -264,6 +264,7 @@ var fmttests = []fmtTest{
 	fmtTest{"%d", "hello", "%d(string=hello)"},
 	fmtTest{"no args", "hello", "no args?(extra string=hello)"},
 	fmtTest{"%s", nil, "%s(<nil>)"},
+	fmtTest{"%T", nil, "<nil>"},
 }
 
 func TestSprintf(t *testing.T) {

src/pkg/fmt/print.go

@@ -1030,6 +1030,10 @@ func (p *pp) doprintf(format string, a []interface{}) {
 
 		// the value's type
 		case 'T':
+			if field == nil {
+				p.buf.Write(nilAngleBytes)
+				break
+			}
 			p.buf.WriteString(reflect.Typeof(field).String())
 
 		default: