Revert "encoding/json: implement Is on SyntaxError"

This reverts CL 253037.

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: I62896717aa47ed491c2c4775d2b05d80e5e9cde3
Reviewed-on: https://go-review.googlesource.com/c/go/+/254837
Trust: Damien Neil <dneil@google.com>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>

diff --git a/src/encoding/json/scanner.go b/src/encoding/json/scanner.go
index 05218f9cc3ec5295b000278fde5f27545ee57d6a..9dc1903e2db24b17d90ab90fb8de930131adb336 100644 (file)
--- a/src/encoding/json/scanner.go
+++ b/src/encoding/json/scanner.go
@@ -49,12 +49,6 @@ type SyntaxError struct {
 
 func (e *SyntaxError) Error() string { return e.msg }
 
-// Is returns true if target is a SyntaxError.
-func (e *SyntaxError) Is(target error) bool {
-       _, ok := target.(*SyntaxError)
-       return ok
-}
-
 // A scanner is a JSON scanning state machine.
 // Callers call scan.reset and then pass bytes in one at a time
 // by calling scan.step(&scan, c) for each byte.

diff --git a/src/encoding/json/scanner_test.go b/src/encoding/json/scanner_test.go
index c12d9bf3d733f6dce9fb148c6e4d276fe4c26e0b..3737516a45065caf94388a183ad6ecb06d1658d0 100644 (file)
--- a/src/encoding/json/scanner_test.go
+++ b/src/encoding/json/scanner_test.go
@@ -6,8 +6,6 @@ package json
 
 import (
        "bytes"
-       "errors"
-       "fmt"
        "math"
        "math/rand"
        "reflect"
@@ -203,13 +201,6 @@ func TestIndentErrors(t *testing.T) {
        }
 }
 
-func TestSyntaxErrorIs(t *testing.T) {
-       err := fmt.Errorf("apackage: %w: failed to parse struct", &SyntaxError{"some error", 43})
-       if !errors.Is(err, &SyntaxError{}) {
-               t.Fatalf("%v should be unwrapped to a SyntaxError", err)
-       }
-}
-
 func diff(t *testing.T, a, b []byte) {
        for i := 0; ; i++ {
                if i >= len(a) || i >= len(b) || a[i] != b[i] {