reflect: implement Type.Overflow* functions

They're already implemented for the Value equivalents. But since Go
1.23, such methods also exist for reflect.Type.

src/reflect/all_test.go

@@ -4897,7 +4897,7 @@ func TestComparable(t *testing.T) {
 	}
 }
 
-func TestOverflow(t *testing.T) {
+func TestValueOverflow(t *testing.T) {
 	if ovf := V(float64(0)).OverflowFloat(1e300); ovf {
 		t.Errorf("%v wrongly overflows float64", 1e300)
 	}
@@ -4936,6 +4936,45 @@ func TestOverflow(t *testing.T) {
 	}
 }
 
+func TestTypeOverflow(t *testing.T) {
+	if ovf := TypeFor[float64]().OverflowFloat(1e300); ovf {
+		t.Errorf("%v wrongly overflows float64", 1e300)
+	}
+
+	maxFloat32 := float64((1<<24 - 1) << (127 - 23))
+	if ovf := TypeFor[float32]().OverflowFloat(maxFloat32); ovf {
+		t.Errorf("%v wrongly overflows float32", maxFloat32)
+	}
+	ovfFloat32 := float64((1<<24-1)<<(127-23) + 1<<(127-52))
+	if ovf := TypeFor[float32]().OverflowFloat(ovfFloat32); !ovf {
+		t.Errorf("%v should overflow float32", ovfFloat32)
+	}
+	if ovf := TypeFor[float32]().OverflowFloat(-ovfFloat32); !ovf {
+		t.Errorf("%v should overflow float32", -ovfFloat32)
+	}
+
+	maxInt32 := int64(0x7fffffff)
+	if ovf := TypeFor[int32]().OverflowInt(maxInt32); ovf {
+		t.Errorf("%v wrongly overflows int32", maxInt32)
+	}
+	if ovf := TypeFor[int32]().OverflowInt(-1 << 31); ovf {
+		t.Errorf("%v wrongly overflows int32", -int64(1)<<31)
+	}
+	ovfInt32 := int64(1 << 31)
+	if ovf := TypeFor[int32]().OverflowInt(ovfInt32); !ovf {
+		t.Errorf("%v should overflow int32", ovfInt32)
+	}
+
+	maxUint32 := uint64(0xffffffff)
+	if ovf := TypeFor[uint32]().OverflowUint(maxUint32); ovf {
+		t.Errorf("%v wrongly overflows uint32", maxUint32)
+	}
+	ovfUint32 := uint64(1 << 32)
+	if ovf := TypeFor[uint32]().OverflowUint(ovfUint32); !ovf {
+		t.Errorf("%v should overflow uint32", ovfUint32)
+	}
+}
+
 /*
 
 func checkSameType(t *testing.T, x Type, y any) {