1 files changed, 24 insertions, 0 deletions
diff --git a/compat/json/borrowed_misc.go b/compat/json/borrowed_misc.go
index 30a3b0e..e6b0162 100644
--- a/compat/json/borrowed_misc.go
+++ b/compat/json/borrowed_misc.go
@@ -4,6 +4,10 @@
 
 package json
 
+import (
+	"reflect"
+)
+
 // A SyntaxError is a description of a JSON syntax error.
 // Unmarshal will return a SyntaxError if the JSON can't be parsed.
 type SyntaxError struct {
@@ -12,3 +16,23 @@ type SyntaxError struct {
 }
 
 func (e *SyntaxError) Error() string { return e.msg }
+
+// A MarshalerError represents an error from calling a MarshalJSON or MarshalText method.
+type MarshalerError struct {
+	Type       reflect.Type
+	Err        error
+	sourceFunc string
+}
+
+func (e *MarshalerError) Error() string {
+	srcFunc := e.sourceFunc
+	if srcFunc == "" {
+		srcFunc = "MarshalJSON"
+	}
+	return "json: error calling " + srcFunc +
+		" for type " + e.Type.String() +
+		": " + e.Err.Error()
+}
+
+// Unwrap returns the underlying error.
+func (e *MarshalerError) Unwrap() error { return e.Err }