encoding/json: use reflect.TypeFor for known types

For #60088

Change-Id: I2e471c76de62944b14472966b63f5778124b9b8b
Reviewed-on: https://go-review.googlesource.com/c/go/+/514655
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Joseph Tsai <joetsai@digital-static.net>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

1 files changed, 3 insertions, 3 deletions

diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index 2142816d88..1119275f51 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -591,7 +591,7 @@ func (d *decodeState) array(v reflect.Value) error {
 }
 
 var nullLiteral = []byte("null")
-var textUnmarshalerType = reflect.TypeOf((*encoding.TextUnmarshaler)(nil)).Elem()
+var textUnmarshalerType = reflect.TypeFor[encoding.TextUnmarshaler]()
 
 // object consumes an object from d.data[d.off-1:], decoding into v.
 // The first byte ('{') of the object has been read already.
@@ -829,12 +829,12 @@ func (d *decodeState) convertNumber(s string) (any, error) {
 	}
 	f, err := strconv.ParseFloat(s, 64)
 	if err != nil {
-		return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeOf(0.0), Offset: int64(d.off)}
+		return nil, &UnmarshalTypeError{Value: "number " + s, Type: reflect.TypeFor[float64](), Offset: int64(d.off)}
 	}
 	return f, nil
 }
 
-var numberType = reflect.TypeOf(Number(""))
+var numberType = reflect.TypeFor[Number]()
 
 // literalStore decodes a literal stored in item into v.
 //