Restricted support for closures encountered in RERS

Thanks to A. Martin for this patch

* transform/functiondefs.go: here.

transform/functiondefs.go

@@ -29,6 +29,7 @@ func G2PFunction_fibonacci(G2PState G2PStateType) []G2PStateType {
 // FunctionDefs visitor type, keeps track of the current function definition.
 type FunctionDefs struct {
 	currentFunction *ast.Object
+	inFuncLit       bool
 }
 
 // Pre traversal applies the transformation.
@@ -63,8 +64,12 @@ func (t *FunctionDefs) Pre(meta *Meta, v *Visitor) bool {
 				},
 			},
 		})
+	case *ast.FuncLit:
+		t.inFuncLit = true
+		return true
+
 	case *ast.ReturnStmt:
-		if len(n.Results) == 0 {
+		if len(n.Results) == 0 || t.inFuncLit {
 			// Either the function returns nothing or we used named return values.
 			return true
 		}
@@ -81,6 +86,12 @@ func (t *FunctionDefs) Pre(meta *Meta, v *Visitor) bool {
 }
 
 // Post traversal does nothing.
-func (FunctionDefs) Post(meta *Meta, v *Visitor) bool {
+func (t *FunctionDefs) Post(meta *Meta, v *Visitor) bool {
+	c := v.Cursor()
+	switch c.Node().(type) {
+	case *ast.FuncLit:
+		t.inFuncLit = false
+	}
+
 	return true
 }