diff --git a/src/encoding/json/decode.go b/src/encoding/json/decode.go
index bc3bd9733d3f54..44f903535896fa 100644
--- a/src/encoding/json/decode.go
+++ b/src/encoding/json/decode.go
@@ -138,7 +138,8 @@ func (e *UnmarshalTypeError) Error() string {
 
 // An UnmarshalFieldError describes a JSON object key that
 // led to an unexported (and therefore unwritable) struct field.
-// (No longer used; kept for compatibility.)
+//
+// Deprecated: No longer used; kept for compatibility.
 type UnmarshalFieldError struct {
 	Key   string
 	Type  reflect.Type
diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go
index d1dda9796af8b6..3f7a8d01751fe2 100644
--- a/src/encoding/json/encode.go
+++ b/src/encoding/json/encode.go
@@ -245,8 +245,8 @@ func (e *UnsupportedValueError) Error() string {
 // attempting to encode a string value with invalid UTF-8 sequences.
 // As of Go 1.2, Marshal instead coerces the string to valid UTF-8 by
 // replacing invalid bytes with the Unicode replacement rune U+FFFD.
-// This error is no longer generated but is kept for backwards compatibility
-// with programs that might mention it.
+//
+// Deprecated: No longer used; kept for compatibility.
 type InvalidUTF8Error struct {
 	S string // the whole string value that caused the error
 }