Inspect return value looking at type and name

Want to check that the `return` statement uses the same variable used in
the `defer` closure. Start inspecting the values to figure out how we
can narrow that down.

Add a test case for a "good" assignment of a returned error in `defer`.

1 files changed, 13 insertions, 0 deletions

diff --git a/testdata/signature.go b/testdata/signature.go
index d780240..c839934 100644
--- a/testdata/signature.go
+++ b/testdata/signature.go
@@ -29,3 +29,16 @@ func doesDeclareErrInSignature() (err error) {
 
 	return nil // want "does not return 'err'"
 }
+
+func good() (err error) {
+	err = nil
+	if err != nil {
+		return err
+	}
+
+	defer func() {
+		err = errors.New("defer error")
+	}()
+
+	return err
+}