Revert "encoding/json: implement Is on all errors"

This reverts CL 254537.

Reason for revert: Reason for revert: The recommended way to check for a type of error is errors.As. API changes should also start with a proposal.

Change-Id: I07c37428575e99c80b17525833a61831d10963bb
Reviewed-on: https://go-review.googlesource.com/c/go/+/254857
Trust: Damien Neil <dneil@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

1 files changed, 0 insertions, 31 deletions

diff --git a/src/encoding/json/decode_test.go b/src/encoding/json/decode_test.go
index b707dcfa99..219e845c7b 100644
--- a/src/encoding/json/decode_test.go
+++ b/src/encoding/json/decode_test.go
@@ -2572,34 +2572,3 @@ func TestUnmarshalMaxDepth(t *testing.T) {
 		}
 	}
 }
-
-func TestInvalidUnmarshalErrorIs(t *testing.T) {
-	err := fmt.Errorf("apackage: %w: failed to parse struct", &InvalidUnmarshalError{reflect.TypeOf("a")})
-	if !errors.Is(err, &InvalidUnmarshalError{}) {
-		t.Fatalf("%v should be unwrapped to a InvalidUnmarshalError", err)
-	}
-}
-
-func TestUnmarshalFieldErrorIs(t *testing.T) {
-	err := fmt.Errorf("apackage: %w: failed to parse struct", &UnmarshalFieldError{
-		Key:   "foo",
-		Type:  reflect.TypeOf("a"),
-		Field: reflect.StructField{Name: "b"},
-	})
-	if !errors.Is(err, &UnmarshalFieldError{}) {
-		t.Fatalf("%v should be unwrapped to a UnmarshalFieldError", err)
-	}
-}
-
-func TestUnmarshalTypeErrorIs(t *testing.T) {
-	err := fmt.Errorf("apackage: %w: failed to parse struct", &UnmarshalTypeError{
-		Value:  "foo",
-		Type:   reflect.TypeOf("a"),
-		Offset: 1,
-		Struct: "Foo",
-		Field:  "Bar",
-	})
-	if !errors.Is(err, &UnmarshalTypeError{}) {
-		t.Fatalf("%v should be unwrapped to a UnmarshalTypeError", err)
-	}
-}