go/types: better doc string for Object.Parent and test

Fixes #14647.

Change-Id: Ib9012a9141e815f5b95f8ca2307e65ffc4587a5b
Reviewed-on: https://go-review.googlesource.com/27370
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/go/types/api_test.go b/src/go/types/api_test.go
index 1d74612dc0feb7c3b5c16e2f88580d26caf9a529..92c6d75e704fbefd5fa69433672365746171da8d 100644 (file)
--- a/src/go/types/api_test.go
+++ b/src/go/types/api_test.go
@@ -1224,3 +1224,74 @@ func TestCompositeLitTypes(t *testing.T) {
                cmptype(rhs.(*ast.CompositeLit).Type, test.typ)
        }
 }
+
+// TestObjectParents verifies that objects have parent scopes or not
+// as specified by the Object interface.
+func TestObjectParents(t *testing.T) {
+       const src = `
+package p
+
+const C = 0
+
+type T1 struct {
+       a, b int
+       T2
+}
+
+type T2 interface {
+       im1()
+       im2()
+}
+
+func (T1) m1() {}
+func (*T1) m2() {}
+
+func f(x int) { y := x; print(y) }
+`
+
+       fset := token.NewFileSet()
+       f, err := parser.ParseFile(fset, "src", src, 0)
+       if err != nil {
+               t.Fatal(err)
+       }
+
+       info := &Info{
+               Defs: make(map[*ast.Ident]Object),
+       }
+       if _, err = new(Config).Check("p", fset, []*ast.File{f}, info); err != nil {
+               t.Fatal(err)
+       }
+
+       for ident, obj := range info.Defs {
+               if obj == nil {
+                       // only package names and implicit vars have a nil object
+                       // (in this test we only need to handle the package name)
+                       if ident.Name != "p" {
+                               t.Errorf("%v has nil object", ident)
+                       }
+                       continue
+               }
+
+               // struct fields, type-associated and interface methods
+               // have no parent scope
+               wantParent := true
+               switch obj := obj.(type) {
+               case *Var:
+                       if obj.IsField() {
+                               wantParent = false
+                       }
+               case *Func:
+                       if obj.Type().(*Signature).Recv() != nil { // method
+                               wantParent = false
+                       }
+               }
+
+               gotParent := obj.Parent() != nil
+               switch {
+               case gotParent && !wantParent:
+                       t.Errorf("%v: want no parent, got %s", ident, obj.Parent())
+               case !gotParent && wantParent:
+                       t.Errorf("%v: no parent found", ident)
+               }
+       }
+}

diff --git a/src/go/types/object.go b/src/go/types/object.go
index 15936f940164f764093e39005f696e8de6000f2d..b83be4336a7c1f6c00c5228d3d5f975369064e5a 100644 (file)
--- a/src/go/types/object.go
+++ b/src/go/types/object.go
@@ -19,7 +19,7 @@ import (
 // All objects implement the Object interface.
 //
 type Object interface {
-       Parent() *Scope // scope in which this object is declared
+       Parent() *Scope // scope in which this object is declared; nil for methods and struct fields
        Pos() token.Pos // position of object identifier in declaration
        Pkg() *Package  // nil for objects in the Universe scope and labels
        Name() string   // package local object name