[dev.typealias] go/types: remove some more vestiges of prior alias implementation

For #18130.

Change-Id: Ibec8efd158d32746978242910dc71e5ed23e9d91
Reviewed-on: https://go-review.googlesource.com/35092
Run-TryBot: Robert Griesemer <gri@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

src/go/types/api_test.go

@@ -1295,155 +1295,3 @@ func f(x int) { y := x; print(y) }
 		}
 	}
 }
-
-// Alias-related code. Keep for now.
-/*
-func TestAliases(t *testing.T) {
-	testenv.MustHaveGoBuild(t)
-
-	const src = `
-package b
-
-import (
-	"./testdata/alias"
-	a "./testdata/alias"
-	"math"
-)
-
-const (
-	c1 = alias.Pi1
-	c2 => a.Pi1
-	c3 => a.Pi2
-	c4 => math.Pi
-)
-
-var (
-	v1 => alias.Default
-	v2 => a.Default
-	v3 = f1
-)
-
-type (
-	t1 => alias.Context
-	t2 => a.Context
-)
-
-func f1 => alias.Sin
-func f2 => a.Sin
-
-func _() {
-	assert(c1 == alias.Pi1 && c2 == a.Pi1 && c3 == a.Pi2 && c4 == math.Pi)
-	assert(c2 == c2 && c2 == c3 && c3 == c4)
-	v1 = v2 // must be assignable
-	var _ *t1 = new(t2) // must be assignable
-	var _ t2 = alias.Default
-	f1(1) // must be callable
-	f2(1)
-	_ = alias.Sin(1)
-	_ = a.Sin(1)
-}
-`
-
-	if out := compile(t, "testdata", "alias.go"); out != "" {
-		defer os.Remove(out)
-	}
-
-	DefPredeclaredTestFuncs() // declare assert built-in for testing
-	mustTypecheck(t, "Aliases", src, nil)
-}
-
-func compile(t *testing.T, dirname, filename string) string {
-	cmd := exec.Command(testenv.GoToolPath(t), "tool", "compile", filename)
-	cmd.Dir = dirname
-	out, err := cmd.CombinedOutput()
-	if err != nil {
-		t.Logf("%s", out)
-		t.Fatalf("go tool compile %s failed: %s", filename, err)
-	}
-	// filename should end with ".go"
-	return filepath.Join(dirname, filename[:len(filename)-2]+"o")
-}
-
-func TestAliasDefUses(t *testing.T) {
-	testenv.MustHaveGoBuild(t)
-
-	const src = `
-package p
-
-import(
-	"go/build"
-	"go/types"
-)
-
-// Defs
-const Invalid => types.Invalid
-type Struct => types.Struct
-var Default => build.Default
-func Implements => types.Implements
-
-// Uses
-const _ = Invalid
-var _ types.Struct = Struct{} // types must be identical
-var _ build.Context = Default
-var _ = Implements(nil, nil)
-`
-
-	info := Info{
-		Defs: make(map[*ast.Ident]Object),
-		Uses: make(map[*ast.Ident]Object),
-	}
-	mustTypecheck(t, "TestAliasDefUses", src, &info)
-
-	// verify Defs
-	defs := map[string]string{
-		"Invalid":    "types.Invalid",
-		"Struct":     "types.Struct",
-		"Default":    "build.Default",
-		"Implements": "types.Implements",
-	}
-
-	for ident, obj := range info.Defs {
-		if alias, ok := obj.(*Alias); ok {
-			if want := defs[ident.Name]; want != "" {
-				orig := alias.Orig()
-				if got := orig.Pkg().Name() + "." + orig.Name(); got != want {
-					t.Errorf("%v: got %v, want %v", ident, got, want)
-				}
-				delete(defs, ident.Name) // mark as found
-			} else {
-				t.Errorf("unexpected alias def of %v", ident)
-			}
-		}
-	}
-
-	if len(defs) != 0 {
-		t.Errorf("missing aliases: %v", defs)
-	}
-
-	// verify Uses
-	uses := map[string]string{
-		"Invalid":    "types.Invalid",
-		"Struct":     "types.Struct",
-		"Default":    "build.Default",
-		"Implements": "types.Implements",
-	}
-
-	for ident, obj := range info.Uses {
-		if alias, ok := obj.(*Alias); ok {
-			if want := uses[ident.Name]; want != "" {
-				orig := alias.Orig()
-				if got := orig.Pkg().Name() + "." + orig.Name(); got != want {
-					t.Errorf("%v: got %v, want %v", ident, got, want)
-				}
-				delete(uses, ident.Name) // mark as found
-			} else {
-				t.Errorf("unexpected alias use of %v", ident)
-			}
-		}
-	}
-
-	if len(uses) != 0 {
-		t.Errorf("missing aliases: %v", defs)
-	}
-}
-*/

src/go/types/call.go

@@ -295,11 +295,6 @@ func (check *Checker) selector(x *operand, e *ast.SelectorExpr) {
 			}
 			check.recordUse(e.Sel, exp)
 
-			// avoid further errors if the imported object is an alias that's broken
-			if exp == nil {
-				goto Error
-			}
-
 			// Simplified version of the code for *ast.Idents:
 			// - imported objects are always fully initialized
 			switch exp := exp.(type) {