Add regression test for polyfloyd#48

errorlint/testdata/src/issues/github-48.go

@@ -0,0 +1,33 @@
+package issues
+
+// Regression test for: https://github.com/polyfloyd/go-errorlint/issues/48
+
+type AssertError struct {
+	reason string
+}
+
+func (e *AssertError) Error() string {
+	return e.reason
+}
+
+func (e *AssertError) Is(target error) bool {
+	terr, ok := target.(*AssertError)
+	return ok && terr.reason == e.reason
+}
+
+type SwitchError struct {
+	reason string
+}
+
+func (e *SwitchError) Error() string {
+	return e.reason
+}
+
+func (e *SwitchError) Is(target error) bool {
+	switch terr := target.(type) {
+	case *SwitchError:
+		return terr.reason == e.reason
+	default:
+		return false
+	}
+}