json: use reflect.TypeFor where possible

Author: extemporalgenome

json/codec.go

@@ -1068,51 +1068,51 @@ type sliceHeader struct {
 
 var (
 	nullType = reflect.TypeOf(nil)
-	boolType = reflect.TypeOf(false)
-
-	intType   = reflect.TypeOf(int(0))
-	int8Type  = reflect.TypeOf(int8(0))
-	int16Type = reflect.TypeOf(int16(0))
-	int32Type = reflect.TypeOf(int32(0))
-	int64Type = reflect.TypeOf(int64(0))
-
-	uintType    = reflect.TypeOf(uint(0))
-	uint8Type   = reflect.TypeOf(uint8(0))
-	uint16Type  = reflect.TypeOf(uint16(0))
-	uint32Type  = reflect.TypeOf(uint32(0))
-	uint64Type  = reflect.TypeOf(uint64(0))
-	uintptrType = reflect.TypeOf(uintptr(0))
-
-	float32Type = reflect.TypeOf(float32(0))
-	float64Type = reflect.TypeOf(float64(0))
-
-	bigIntType     = reflect.TypeOf(new(big.Int))
-	numberType     = reflect.TypeOf(json.Number(""))
-	stringType     = reflect.TypeOf("")
-	stringsType    = reflect.TypeOf([]string(nil))
-	bytesType      = reflect.TypeOf(([]byte)(nil))
-	durationType   = reflect.TypeOf(time.Duration(0))
-	timeType       = reflect.TypeOf(time.Time{})
-	rawMessageType = reflect.TypeOf(RawMessage(nil))
+	boolType = reflect.TypeFor[bool]()
+
+	intType   = reflect.TypeFor[int]()
+	int8Type  = reflect.TypeFor[int8]()
+	int16Type = reflect.TypeFor[int16]()
+	int32Type = reflect.TypeFor[int32]()
+	int64Type = reflect.TypeFor[int64]()
+
+	uintType    = reflect.TypeFor[uint]()
+	uint8Type   = reflect.TypeFor[uint8]()
+	uint16Type  = reflect.TypeFor[uint16]()
+	uint32Type  = reflect.TypeFor[uint32]()
+	uint64Type  = reflect.TypeFor[uint64]()
+	uintptrType = reflect.TypeFor[uintptr]()
+
+	float32Type = reflect.TypeFor[float32]()
+	float64Type = reflect.TypeFor[float64]()
+
+	bigIntType     = reflect.TypeFor[*big.Int]()
+	numberType     = reflect.TypeFor[json.Number]()
+	stringType     = reflect.TypeFor[string]()
+	stringsType    = reflect.TypeFor[[]string]()
+	bytesType      = reflect.TypeFor[[]byte]()
+	durationType   = reflect.TypeFor[time.Duration]()
+	timeType       = reflect.TypeFor[time.Time]()
+	rawMessageType = reflect.TypeFor[RawMessage]()
 
 	numberPtrType     = reflect.PtrTo(numberType)
 	durationPtrType   = reflect.PtrTo(durationType)
 	timePtrType       = reflect.PtrTo(timeType)
 	rawMessagePtrType = reflect.PtrTo(rawMessageType)
 
-	sliceInterfaceType       = reflect.TypeOf(([]any)(nil))
-	sliceStringType          = reflect.TypeOf(([]any)(nil))
-	mapStringInterfaceType   = reflect.TypeOf((map[string]any)(nil))
-	mapStringRawMessageType  = reflect.TypeOf((map[string]RawMessage)(nil))
-	mapStringStringType      = reflect.TypeOf((map[string]string)(nil))
-	mapStringStringSliceType = reflect.TypeOf((map[string][]string)(nil))
-	mapStringBoolType        = reflect.TypeOf((map[string]bool)(nil))
-
-	interfaceType       = reflect.TypeOf((*any)(nil)).Elem()
-	jsonMarshalerType   = reflect.TypeOf((*Marshaler)(nil)).Elem()
-	jsonUnmarshalerType = reflect.TypeOf((*Unmarshaler)(nil)).Elem()
-	textMarshalerType   = reflect.TypeOf((*encoding.TextMarshaler)(nil)).Elem()
-	textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+	sliceInterfaceType       = reflect.TypeFor[[]any]()
+	sliceStringType          = reflect.TypeFor[[]any]()
+	mapStringInterfaceType   = reflect.TypeFor[map[string]any]()
+	mapStringRawMessageType  = reflect.TypeFor[map[string]RawMessage]()
+	mapStringStringType      = reflect.TypeFor[map[string]string]()
+	mapStringStringSliceType = reflect.TypeFor[map[string][]string]()
+	mapStringBoolType        = reflect.TypeFor[map[string]bool]()
+
+	interfaceType       = reflect.TypeFor[any]()
+	jsonMarshalerType   = reflect.TypeFor[Marshaler]()
+	jsonUnmarshalerType = reflect.TypeFor[Unmarshaler]()
+	textMarshalerType   = reflect.TypeFor[encoding.TextMarshaler]()
+	textUnmarshalerType = reflect.TypeFor[encoding.TextUnmarshaler]()
 
 	bigIntDecoder = constructJSONUnmarshalerDecodeFunc(bigIntType, false)
 )