update

Change-Id: Id8d5f247884fbe189a4c778203ea7cf575b1a93a

Author: mateusz834

src/reflect/all_test.go

@@ -8747,6 +8747,14 @@ func TestTypeAssertInterfaceTypes(t *testing.T) {
 	if v != fmt.Stringer(val) || !ok {
 		t.Errorf(`TypeAssert[fmt.Stringer](&testTypeWithMethod{"test"}) = (%v, %v); want = (&testTypeWithMethod{"test"}, true)`, v, ok)
 	}
+
+	if v, ok := TypeAssert[int](ValueOf(newPtr(any(1))).Elem()); v != 1 || !ok {
+		t.Errorf(`TypeAssert[int](ValueOf(newPtr(any(1))).Elem()) = (%v, %v); want = (1, true)`, v, ok)
+	}
+
+	if v, ok := TypeAssert[testTypeWithMethod](ValueOf(newPtr(fmt.Stringer(testTypeWithMethod{"test"}))).Elem()); v.val != "test" || !ok {
+		t.Errorf(`TypeAssert[testTypeWithMethod](newPtr(fmt.Stringer(testTypeWithMethod{"test"}))) = (%v, %v); want = (testTypeWithMethod{"test"}, true)`, v, ok)
+	}
 }
 
 type testTypeWithMethod struct {
@@ -8789,3 +8797,10 @@ func TestTypeAssertAllocs(t *testing.T) {
 		t.Errorf("unexpected amount of allocations = %v; want = 0", allocs)
 	}
 }
+
+func BenchmarkTypeAssertTime(b *testing.B) {
+	val := ValueOf(time.Now())
+	for b.Loop() {
+		TypeAssert[time.Time](val)
+	}
+}

src/reflect/value.go

@@ -1539,14 +1539,29 @@ func TypeAssert[T any](v Value) (T, bool) {
 			v, ok := packEface(v).(T)
 			return v, ok
 		}
+
+		// Special case: match the element inside the interface.
+		// TypeAssert[int](ValueOf(newPtr(any(0))).Elem()
+		if v.kind() == Interface {
+			// Empty interface has one layout, all interfaces with
+			// methods have a second layout.
+			if v.NumMethod() == 0 {
+				v, ok := (*(*any)(v.ptr)).(T)
+				return v, ok
+			}
+			v, ok := any(*(*interface {
+				M()
+			})(v.ptr)).(T)
+			return v, ok
+		}
+
 		var zero T
 		return zero, false
 	}
 
-	if v.typ().IsDirectIface() {
+	if v.flag&flagIndir == 0 {
 		return *(*T)(unsafe.Pointer(&v.ptr)), true
 	}
-
 	return *(*T)(v.ptr), true
 }