go/pointer: support reflect.Value in AddExtendedQuery

We were calling types.Type.Underlying() too early, which caused CanPoint
to see an ordinary struct, not reflect.Value.

Change-Id: I23ba3b9451bc1abc1ad8a45c790d2e22c1481f26
Reviewed-on: https://go-review.googlesource.com/129196
Run-TryBot: Dominik Honnef <dominik@honnef.co>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>

go/pointer/api.go

@@ -132,7 +132,7 @@ func (c *Config) AddIndirectQuery(v ssa.Value) {
 // 	// 'type T struct { F *int }', the following query will access the field F.
 // 	c.AddExtendedQuery(v, "x[1][0].F")
 func (c *Config) AddExtendedQuery(v ssa.Value, query string) (*Pointer, error) {
-	ops, _, err := parseExtendedQuery(v.Type().Underlying(), query)
+	ops, _, err := parseExtendedQuery(v.Type(), query)
 	if err != nil {
 		return nil, fmt.Errorf("invalid query %q: %s", query, err)
 	}

go/pointer/query.go

@@ -67,7 +67,7 @@ func destructuringOps(typ types.Type, expr ast.Expr) ([]interface{}, types.Type,
 		}
 
 		var structT *types.Struct
-		switch typ := typ.(type) {
+		switch typ := typ.Underlying().(type) {
 		case *types.Pointer:
 			var ok bool
 			structT, ok = typ.Elem().Underlying().(*types.Struct)
@@ -107,7 +107,7 @@ func destructuringOps(typ types.Type, expr ast.Expr) ([]interface{}, types.Type,
 		if err != nil {
 			return nil, nil, err
 		}
-		switch typ := typ.(type) {
+		switch typ := typ.Underlying().(type) {
 		case *types.Array:
 			out = append(out, "arrayelem")
 			return out, typ.Elem().Underlying(), nil

go/pointer/query_test.go

@@ -1,17 +1,20 @@
 package pointer
 
 import (
-	"go/ast"
-	"go/parser"
-	"go/token"
-	"go/types"
 	"reflect"
 	"testing"
+
+	"golang.org/x/tools/go/loader"
 )
 
 func TestParseExtendedQuery(t *testing.T) {
 	const myprog = `
 package pkg
+
+import "reflect"
+
+type T []*int
+
 var V1 *int
 var V2 **int
 var V3 []*int
@@ -19,6 +22,8 @@ var V4 chan []*int
 var V5 struct {F1, F2 chan *int}
 var V6 [1]chan *int
 var V7 int
+var V8 T
+var V9 reflect.Value
 `
 	tests := []struct {
 		in    string
@@ -27,8 +32,10 @@ var V7 int
 		valid bool
 	}{
 		{`x`, []interface{}{"x"}, "V1", true},
+		{`x`, []interface{}{"x"}, "V9", true},
 		{`*x`, []interface{}{"x", "load"}, "V2", true},
 		{`x[0]`, []interface{}{"x", "sliceelem"}, "V3", true},
+		{`x[0]`, []interface{}{"x", "sliceelem"}, "V8", true},
 		{`<-x`, []interface{}{"x", "recv"}, "V4", true},
 		{`(<-x)[0]`, []interface{}{"x", "recv", "sliceelem"}, "V4", true},
 		{`<-x.F2`, []interface{}{"x", "field", 1, "recv"}, "V5", true},
@@ -40,19 +47,20 @@ var V7 int
 		{`close(x)`, nil, "V1", false},
 	}
 
-	fset := token.NewFileSet()
+	var conf loader.Config
-	f, err := parser.ParseFile(fset, "file.go", myprog, 0)
+	f, err := conf.ParseFile("file.go", myprog)
 	if err != nil {
 		t.Fatal(err)
 	}
-	cfg := &types.Config{}
+	conf.CreateFromFiles("main", f)
-	pkg, err := cfg.Check("main", fset, []*ast.File{f}, nil)
+	lprog, err := conf.Load()
 	if err != nil {
 		t.Fatal(err)
 	}
+	pkg := lprog.Created[0].Pkg
 
 	for _, test := range tests {
-		typ := pkg.Scope().Lookup(test.v).Type().Underlying()
+		typ := pkg.Scope().Lookup(test.v).Type()
 		ops, _, err := parseExtendedQuery(typ, test.in)
 		if test.valid && err != nil {
 			t.Errorf("parseExtendedQuery(%q) = %s, expected no error", test.in, err)