gopls/internal/regtest/misc/references_test.go - tools - Git at Google

 // Copyright 2020 The Go Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.

 package misc

 import (
 	"fmt"
 	"os"
 	"path/filepath"
 	"reflect"
 	"sort"
 	"strings"
 	"testing"

 	"github.com/google/go-cmp/cmp"
 	"golang.org/x/tools/gopls/internal/lsp/protocol"
 	"golang.org/x/tools/gopls/internal/lsp/regtest"
 	. "golang.org/x/tools/gopls/internal/lsp/regtest"
 	"golang.org/x/tools/internal/testenv"
 )

 func TestStdlibReferences(t *testing.T) {
 	const files = `
 -- go.mod --
 module mod.com

 go 1.12
 -- main.go --
 package main

 import "fmt"

 func main() {
 	fmt.Print()
 }
 `

 	Run(t, files, func(t *testing.T, env *Env) {
 		env.OpenFile("main.go")
 		loc := env.GoToDefinition(env.RegexpSearch("main.go", `fmt.(Print)`))
 		refs, err := env.Editor.References(env.Ctx, loc)
 		if err != nil {
 			t.Fatal(err)
 		}
 		if len(refs) != 2 {
 			// TODO(adonovan): make this assertion less maintainer-hostile.
 			t.Fatalf("got %v reference(s), want 2", len(refs))
 		}
 		// The first reference is guaranteed to be the definition.
 		if got, want := refs[1].URI, env.Sandbox.Workdir.URI("main.go"); got != want {
 			t.Errorf("found reference in %v, wanted %v", got, want)
 		}
 	})
 }

 // This is a regression test for golang/go#48400 (a panic).
 func TestReferencesOnErrorMethod(t *testing.T) {
 	// Ideally this would actually return the correct answer,
 	// instead of merely failing gracefully.
 	const files = `
 -- go.mod --
 module mod.com

 go 1.12
 -- main.go --
 package main

 type t interface {
 	error
 }

 type s struct{}

 func (*s) Error() string {
 	return ""
 }

 func _() {
 	var s s
 	_ = s.Error()
 }
 `
 	Run(t, files, func(t *testing.T, env *Env) {
 		env.OpenFile("main.go")
 		loc := env.GoToDefinition(env.RegexpSearch("main.go", `Error`))
 		refs, err := env.Editor.References(env.Ctx, loc)
 		if err != nil {
 			t.Fatalf("references on (*s).Error failed: %v", err)
 		}
 		// TODO(adonovan): this test is crying out for marker support in regtests.
 		var buf strings.Builder
 		for _, ref := range refs {
 			fmt.Fprintf(&buf, "%s %s\n", env.Sandbox.Workdir.URIToPath(ref.URI), ref.Range)
 		}
 		got := buf.String()
 		want := "main.go 8:10-8:15\n" + // (*s).Error decl
 			"main.go 14:7-14:12\n" // s.Error() call
 		if diff := cmp.Diff(want, got); diff != "" {
 			t.Errorf("unexpected references on (*s).Error (-want +got):\n%s", diff)
 		}
 	})
 }

 func TestDefsRefsBuiltins(t *testing.T) {
 	testenv.NeedsGo1Point(t, 17) // for unsafe.{Add,Slice}
 	// TODO(adonovan): add unsafe.SliceData,String,StringData} in later go versions.
 	const files = `
 -- go.mod --
 module example.com
 go 1.16

 -- a.go --
 package a

 import "unsafe"

 const _ = iota
 var _ error
 var _ int
 var _ = append()
 var _ = unsafe.Pointer(nil)
 var _ = unsafe.Add(nil, nil)
 var _ = unsafe.Sizeof(0)
 var _ = unsafe.Alignof(0)
 var _ = unsafe.Slice(nil, 0)
 `

 	Run(t, files, func(t *testing.T, env *Env) {
 		env.OpenFile("a.go")
 		for _, name := range strings.Fields(
 			"iota error int nil append iota Pointer Sizeof Alignof Add Slice") {
 			loc := env.RegexpSearch("a.go", `\b`+name+`\b`)

 			// definition -> {builtin,unsafe}.go
 			def, err := env.Editor.GoToDefinition(env.Ctx, loc)
 			if err != nil {
 				t.Errorf("definition(%q) failed: %v", name, err)
 			} else if (!strings.HasSuffix(string(def.URI), "builtin.go") &&
 				!strings.HasSuffix(string(def.URI), "unsafe.go")) ||
 				def.Range.Start.Line == 0 {
 				t.Errorf("definition(%q) = %v, want {builtin,unsafe}.go",
 					name, def)
 			}

 			// "references to (builtin "Foo"|unsafe.Foo) are not supported"
 			_, err = env.Editor.References(env.Ctx, loc)
 			gotErr := fmt.Sprint(err)
 			if !strings.Contains(gotErr, "references to") ||
 				!strings.Contains(gotErr, "not supported") ||
 				!strings.Contains(gotErr, name) {
 				t.Errorf("references(%q) error: got %q, want %q",
 					name, gotErr, "references to ... are not supported")
 			}
 		}
 	})
 }

 func TestPackageReferences(t *testing.T) {
 	tests := []struct {
 		packageName  string
 		wantRefCount int
 		wantFiles    []string
 	}{
 		{
 			"lib1",
 			3,
 			[]string{
 				"main.go",
 				"lib1/a.go",
 				"lib1/b.go",
 			},
 		},
 		{
 			"lib2",
 			2,
 			[]string{
 				"main.go",
 				"lib2/a.go",
 			},
 		},
 	}

 	const files = `
 -- go.mod --
 module mod.com

 go 1.18
 -- lib1/a.go --
 package lib1

 const A = 1

 -- lib1/b.go --
 package lib1

 const B = 1

 -- lib2/a.go --
 package lib2

 const C = 1

 -- main.go --
 package main

 import (
 	"mod.com/lib1"
 	"mod.com/lib2"
 )

 func main() {
 	println("Hello")
 }
 `
 	Run(t, files, func(t *testing.T, env *Env) {
 		for _, test := range tests {
 			file := fmt.Sprintf("%s/a.go", test.packageName)
 			env.OpenFile(file)
 			loc := env.RegexpSearch(file, test.packageName)
 			refs := env.References(loc)
 			if len(refs) != test.wantRefCount {
 				// TODO(adonovan): make this assertion less maintainer-hostile.
 				t.Fatalf("got %v reference(s), want %d", len(refs), test.wantRefCount)
 			}
 			var refURIs []string
 			for _, ref := range refs {
 				refURIs = append(refURIs, string(ref.URI))
 			}
 			for _, base := range test.wantFiles {
 				hasBase := false
 				for _, ref := range refURIs {
 					if strings.HasSuffix(ref, base) {
 						hasBase = true
 						break
 					}
 				}
 				if !hasBase {
 					t.Fatalf("got [%v], want reference ends with \"%v\"", strings.Join(refURIs, ","), base)
 				}
 			}
 		}
 	})
 }

 // Test for golang/go#43144.
 //
 // Verify that we search for references and implementations in intermediate
 // test variants.
 func TestReferencesInTestVariants(t *testing.T) {
 	const files = `
 -- go.mod --
 module foo.mod

 go 1.12
 -- foo/foo.go --
 package foo

 import "foo.mod/bar"

 const Foo = 42

 type T int
 type InterfaceM interface{ M() }
 type InterfaceF interface{ F() }

 func _() {
 	_ = bar.Blah
 }

 -- foo/foo_test.go --
 package foo

 type Fer struct{}
 func (Fer) F() {}

 -- bar/bar.go --
 package bar

 var Blah = 123

 -- bar/bar_test.go --
 package bar

 type Mer struct{}
 func (Mer) M() {}

 func TestBar() {
 	_ = Blah
 }
 -- bar/bar_x_test.go --
 package bar_test

 import (
 	"foo.mod/bar"
 	"foo.mod/foo"
 )

 type Mer struct{}
 func (Mer) M() {}

 func _() {
 	_ = bar.Blah
 	_ = foo.Foo
 }
 `

 	Run(t, files, func(t *testing.T, env *Env) {
 		env.OpenFile("foo/foo.go")

 		refTests := []struct {
 			re       string
 			wantRefs []string
 		}{
 			// Blah is referenced:
 			// - inside the foo.mod/bar (ordinary) package
 			// - inside the foo.mod/bar [foo.mod/bar.test] test variant package
 			// - from the foo.mod/bar_test [foo.mod/bar.test] x_test package
 			// - from the foo.mod/foo package
 			{"Blah", []string{"bar/bar.go:3", "bar/bar_test.go:7", "bar/bar_x_test.go:12", "foo/foo.go:12"}},

 			// Foo is referenced in bar_x_test.go via the intermediate test variant
 			// foo.mod/foo [foo.mod/bar.test].
 			{"Foo", []string{"bar/bar_x_test.go:13", "foo/foo.go:5"}},
 		}

 		for _, test := range refTests {
 			loc := env.RegexpSearch("foo/foo.go", test.re)
 			refs := env.References(loc)

 			got := fileLocations(env, refs)
 			if diff := cmp.Diff(test.wantRefs, got); diff != "" {
 				t.Errorf("References(%q) returned unexpected diff (-want +got):\n%s", test.re, diff)
 			}
 		}

 		implTests := []struct {
 			re        string
 			wantImpls []string
 		}{
 			// InterfaceM is implemented both in foo.mod/bar [foo.mod/bar.test] (which
 			// doesn't import foo), and in foo.mod/bar_test [foo.mod/bar.test], which
 			// imports the test variant of foo.
 			{"InterfaceM", []string{"bar/bar_test.go:3", "bar/bar_x_test.go:8"}},

 			// A search within the ordinary package to should find implementations
 			// (Fer) within the augmented test package.
 			{"InterfaceF", []string{"foo/foo_test.go:3"}},
 		}

 		for _, test := range implTests {
 			loc := env.RegexpSearch("foo/foo.go", test.re)
 			impls := env.Implementations(loc)

 			got := fileLocations(env, impls)
 			if diff := cmp.Diff(test.wantImpls, got); diff != "" {
 				t.Errorf("Implementations(%q) returned unexpected diff (-want +got):\n%s", test.re, diff)
 			}
 		}
 	})
 }

 // This is a regression test for Issue #56169, in which interface
 // implementations in vendored modules were not found. The actual fix
 // was the same as for #55995; see TestVendoringInvalidatesMetadata.
 func TestImplementationsInVendor(t *testing.T) {
 	t.Skip("golang/go#56169: file watching does not capture vendor dirs")

 	const proxy = `
 -- other.com/b@v1.0.0/go.mod --
 module other.com/b
 go 1.14

 -- other.com/b@v1.0.0/b.go --
 package b
 type B int
 func (B) F() {}
 `
 	const src = `
 -- go.mod --
 module example.com/a
 go 1.14
 require other.com/b v1.0.0

 -- go.sum --
 other.com/b v1.0.0 h1:9WyCKS+BLAMRQM0CegP6zqP2beP+ShTbPaARpNY31II=
 other.com/b v1.0.0/go.mod h1:TgHQFucl04oGT+vrUm/liAzukYHNxCwKNkQZEyn3m9g=

 -- a.go --
 package a
 import "other.com/b"
 type I interface { F() }
 var _ b.B

 `
 	WithOptions(
 		ProxyFiles(proxy),
 		Modes(Default), // fails in 'experimental' mode
 	).Run(t, src, func(t *testing.T, env *Env) {
 		// Enable to debug go.sum mismatch, which may appear as
 		// "module lookup disabled by GOPROXY=off", confusingly.
 		if false {
 			env.DumpGoSum(".")
 		}

 		checkVendor := func(locs []protocol.Location, wantVendor bool) {
 			if len(locs) != 1 {
 				t.Errorf("got %d locations, want 1", len(locs))
 			} else if strings.Contains(string(locs[0].URI), "/vendor/") != wantVendor {
 				t.Errorf("got location %s, wantVendor=%t", locs[0], wantVendor)
 			}
 		}

 		env.OpenFile("a.go")
 		refLoc := env.RegexpSearch("a.go", "I") // find "I" reference

 		// Initially, a.I has one implementation b.B in
 		// the module cache, not the vendor tree.
 		checkVendor(env.Implementations(refLoc), false)

 		// Run 'go mod vendor' outside the editor.
 		if err := env.Sandbox.RunGoCommand(env.Ctx, ".", "mod", []string{"vendor"}, nil, true); err != nil {
 			t.Fatalf("go mod vendor: %v", err)
 		}

 		// Synchronize changes to watched files.
 		env.Await(env.DoneWithChangeWatchedFiles())

 		// Now, b.B is found in the vendor tree.
 		checkVendor(env.Implementations(refLoc), true)

 		// Delete the vendor tree.
 		if err := os.RemoveAll(env.Sandbox.Workdir.AbsPath("vendor")); err != nil {
 			t.Fatal(err)
 		}
 		// Notify the server of the deletion.
 		if err := env.Sandbox.Workdir.CheckForFileChanges(env.Ctx); err != nil {
 			t.Fatal(err)
 		}

 		// Synchronize again.
 		env.Await(env.DoneWithChangeWatchedFiles())

 		// b.B is once again defined in the module cache.
 		checkVendor(env.Implementations(refLoc), false)
 	})
 }

 // This test can't be expressed as a marker test because the marker
 // test framework opens all files (which is a bit of a hack), creating
 // a <command-line-arguments> package for packages that otherwise
 // wouldn't be found from the go.work file.
 func TestReferencesFromWorkspacePackages59674(t *testing.T) {
 	testenv.NeedsGo1Point(t, 18) // for go.work support
 	const src = `
 -- a/go.mod --
 module example.com/a
 go 1.12

 -- b/go.mod --
 module example.com/b
 go 1.12

 -- c/go.mod --
 module example.com/c
 go 1.12

 -- lib/go.mod --
 module example.com/lib
 go 1.12

 -- go.work --
 use ./a
 use ./b
 // don't use ./c
 use ./lib

 -- a/a.go --
 package a

 import "example.com/lib"

 var _ = lib.F // query here

 -- b/b.go --
 package b

 import "example.com/lib"

 var _ = lib.F // also found by references

 -- c/c.go --
 package c

 import "example.com/lib"

 var _ = lib.F // this reference should not be reported

 -- lib/lib.go --
 package lib

 func F() {} // declaration
 `
 	Run(t, src, func(t *testing.T, env *Env) {
 		env.OpenFile("a/a.go")
 		refLoc := env.RegexpSearch("a/a.go", "F")
 		got := fileLocations(env, env.References(refLoc))
 		want := []string{"a/a.go:5", "b/b.go:5", "lib/lib.go:3"}
 		if diff := cmp.Diff(want, got); diff != "" {
 			t.Errorf("incorrect References (-want +got):\n%s", diff)
 		}
 	})
 }

 // Test an 'implementation' query on a type that implements 'error'.
 // (Unfortunately builtin locations cannot be expressed using @loc
 // in the marker test framework.)
 func TestImplementationsOfError(t *testing.T) {
 	const src = `
 -- go.mod --
 module example.com
 go 1.12

 -- a.go --
 package a

 type Error2 interface {
 	Error() string
 }

 type MyError int
 func (MyError) Error() string { return "" }

 type MyErrorPtr int
 func (*MyErrorPtr) Error() string { return "" }
 `
 	Run(t, src, func(t *testing.T, env *Env) {
 		env.OpenFile("a.go")

 		for _, test := range []struct {
 			re   string
 			want []string
 		}{
 			// error type
 			{"Error2", []string{"a.go:10", "a.go:7", "std:builtin/builtin.go"}},
 			{"MyError", []string{"a.go:3", "std:builtin/builtin.go"}},
 			{"MyErrorPtr", []string{"a.go:3", "std:builtin/builtin.go"}},
 			// error.Error method
 			{"(Error).. string", []string{"a.go:11", "a.go:8", "std:builtin/builtin.go"}},
 			{"MyError. (Error)", []string{"a.go:4", "std:builtin/builtin.go"}},
 			{"MyErrorPtr. (Error)", []string{"a.go:4", "std:builtin/builtin.go"}},
 		} {
 			matchLoc := env.RegexpSearch("a.go", test.re)
 			impls := env.Implementations(matchLoc)
 			got := fileLocations(env, impls)
 			if !reflect.DeepEqual(got, test.want) {
 				t.Errorf("Implementations(%q) = %q, want %q",
 					test.re, got, test.want)
 			}
 		}
 	})
 }

 // fileLocations returns a new sorted array of the
 // relative file name and line number of each location.
 // Duplicates are not removed.
 // Standard library filenames are abstracted for robustness.
 func fileLocations(env *regtest.Env, locs []protocol.Location) []string {
 	got := make([]string, 0, len(locs))
 	for _, loc := range locs {
 		path := env.Sandbox.Workdir.URIToPath(loc.URI) // (slashified)
 		if i := strings.Index(path, "/src/"); i >= 0 && filepath.IsAbs(path) {
 			// Absolute path with "src" segment: assume it's in GOROOT.
 			// Strip directory and don't add line/column since they are fragile.
 			path = "std:" + path[i+len("/src/"):]
 		} else {
 			path = fmt.Sprintf("%s:%d", path, loc.Range.Start.Line+1)
 		}
 		got = append(got, path)
 	}
 	sort.Strings(got)
 	return got
 }
	// Copyright 2020 The Go Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style
	// license that can be found in the LICENSE file.

	package misc

	import (
	"fmt"
	"os"
	"path/filepath"
	"reflect"
	"sort"
	"strings"
	"testing"

	"github.com/google/go-cmp/cmp"
	"golang.org/x/tools/gopls/internal/lsp/protocol"
	"golang.org/x/tools/gopls/internal/lsp/regtest"
	. "golang.org/x/tools/gopls/internal/lsp/regtest"
	"golang.org/x/tools/internal/testenv"
	)

	func TestStdlibReferences(t *testing.T) {
	const files = `
	-- go.mod --
	module mod.com

	go 1.12
	-- main.go --
	package main

	import "fmt"

	func main() {
	fmt.Print()
	}
	`

	Run(t, files, func(t testing.T, env Env) {
	env.OpenFile("main.go")
	loc := env.GoToDefinition(env.RegexpSearch("main.go", `fmt.(Print)`))
	refs, err := env.Editor.References(env.Ctx, loc)
	if err != nil {
	t.Fatal(err)
	}
	if len(refs) != 2 {
	// TODO(adonovan): make this assertion less maintainer-hostile.
	t.Fatalf("got %v reference(s), want 2", len(refs))
	}
	// The first reference is guaranteed to be the definition.
	if got, want := refs[1].URI, env.Sandbox.Workdir.URI("main.go"); got != want {
	t.Errorf("found reference in %v, wanted %v", got, want)
	}
	})
	}

	// This is a regression test for golang/go#48400 (a panic).
	func TestReferencesOnErrorMethod(t *testing.T) {
	// Ideally this would actually return the correct answer,
	// instead of merely failing gracefully.
	const files = `
	-- go.mod --
	module mod.com

	go 1.12
	-- main.go --
	package main

	type t interface {
	error
	}

	type s struct{}

	func (*s) Error() string {
	return ""
	}

	func _() {
	var s s
	_ = s.Error()
	}
	`
	Run(t, files, func(t testing.T, env Env) {
	env.OpenFile("main.go")
	loc := env.GoToDefinition(env.RegexpSearch("main.go", `Error`))
	refs, err := env.Editor.References(env.Ctx, loc)
	if err != nil {
	t.Fatalf("references on (*s).Error failed: %v", err)
	}
	// TODO(adonovan): this test is crying out for marker support in regtests.
	var buf strings.Builder
	for _, ref := range refs {
	fmt.Fprintf(&buf, "%s %s\n", env.Sandbox.Workdir.URIToPath(ref.URI), ref.Range)
	}
	got := buf.String()
	want := "main.go 8:10-8:15\n" + // (*s).Error decl
	"main.go 14:7-14:12\n" // s.Error() call
	if diff := cmp.Diff(want, got); diff != "" {
	t.Errorf("unexpected references on (*s).Error (-want +got):\n%s", diff)
	}
	})
	}

	func TestDefsRefsBuiltins(t *testing.T) {
	testenv.NeedsGo1Point(t, 17) // for unsafe.{Add,Slice}
	// TODO(adonovan): add unsafe.SliceData,String,StringData} in later go versions.
	const files = `
	-- go.mod --
	module example.com
	go 1.16

	-- a.go --
	package a

	import "unsafe"

	const _ = iota
	var _ error
	var _ int
	var _ = append()
	var _ = unsafe.Pointer(nil)
	var _ = unsafe.Add(nil, nil)
	var _ = unsafe.Sizeof(0)
	var _ = unsafe.Alignof(0)
	var _ = unsafe.Slice(nil, 0)
	`

	Run(t, files, func(t testing.T, env Env) {
	env.OpenFile("a.go")
	for _, name := range strings.Fields(
	"iota error int nil append iota Pointer Sizeof Alignof Add Slice") {
	loc := env.RegexpSearch("a.go", `\b`+name+`\b`)

	// definition -> {builtin,unsafe}.go
	def, err := env.Editor.GoToDefinition(env.Ctx, loc)
	if err != nil {
	t.Errorf("definition(%q) failed: %v", name, err)
	} else if (!strings.HasSuffix(string(def.URI), "builtin.go") &&
	!strings.HasSuffix(string(def.URI), "unsafe.go")) \|\|
	def.Range.Start.Line == 0 {
	t.Errorf("definition(%q) = %v, want {builtin,unsafe}.go",
	name, def)
	}

	// "references to (builtin "Foo"\|unsafe.Foo) are not supported"
	_, err = env.Editor.References(env.Ctx, loc)
	gotErr := fmt.Sprint(err)
	if !strings.Contains(gotErr, "references to") \|\|
	!strings.Contains(gotErr, "not supported") \|\|
	!strings.Contains(gotErr, name) {
	t.Errorf("references(%q) error: got %q, want %q",
	name, gotErr, "references to ... are not supported")
	}
	}
	})
	}

	func TestPackageReferences(t *testing.T) {
	tests := []struct {
	packageName string
	wantRefCount int
	wantFiles []string
	}{
	{
	"lib1",
	3,
	[]string{
	"main.go",
	"lib1/a.go",
	"lib1/b.go",
	},
	},
	{
	"lib2",
	2,
	[]string{
	"main.go",
	"lib2/a.go",
	},
	},
	}

	const files = `
	-- go.mod --
	module mod.com

	go 1.18
	-- lib1/a.go --
	package lib1

	const A = 1

	-- lib1/b.go --
	package lib1

	const B = 1

	-- lib2/a.go --
	package lib2

	const C = 1

	-- main.go --
	package main

	import (
	"mod.com/lib1"
	"mod.com/lib2"
	)

	func main() {
	println("Hello")
	}
	`
	Run(t, files, func(t testing.T, env Env) {
	for _, test := range tests {
	file := fmt.Sprintf("%s/a.go", test.packageName)
	env.OpenFile(file)
	loc := env.RegexpSearch(file, test.packageName)
	refs := env.References(loc)
	if len(refs) != test.wantRefCount {
	// TODO(adonovan): make this assertion less maintainer-hostile.
	t.Fatalf("got %v reference(s), want %d", len(refs), test.wantRefCount)
	}
	var refURIs []string
	for _, ref := range refs {
	refURIs = append(refURIs, string(ref.URI))
	}
	for _, base := range test.wantFiles {
	hasBase := false
	for _, ref := range refURIs {
	if strings.HasSuffix(ref, base) {
	hasBase = true
	break
	}
	}
	if !hasBase {
	t.Fatalf("got [%v], want reference ends with \"%v\"", strings.Join(refURIs, ","), base)
	}
	}
	}
	})
	}

	// Test for golang/go#43144.
	//
	// Verify that we search for references and implementations in intermediate
	// test variants.
	func TestReferencesInTestVariants(t *testing.T) {
	const files = `
	-- go.mod --
	module foo.mod

	go 1.12
	-- foo/foo.go --
	package foo

	import "foo.mod/bar"

	const Foo = 42

	type T int
	type InterfaceM interface{ M() }
	type InterfaceF interface{ F() }

	func _() {
	_ = bar.Blah
	}

	-- foo/foo_test.go --
	package foo

	type Fer struct{}
	func (Fer) F() {}

	-- bar/bar.go --
	package bar

	var Blah = 123

	-- bar/bar_test.go --
	package bar

	type Mer struct{}
	func (Mer) M() {}

	func TestBar() {
	_ = Blah
	}
	-- bar/bar_x_test.go --
	package bar_test

	import (
	"foo.mod/bar"
	"foo.mod/foo"
	)

	type Mer struct{}
	func (Mer) M() {}

	func _() {
	_ = bar.Blah
	_ = foo.Foo
	}
	`

	Run(t, files, func(t testing.T, env Env) {
	env.OpenFile("foo/foo.go")

	refTests := []struct {
	re string
	wantRefs []string
	}{
	// Blah is referenced:
	// - inside the foo.mod/bar (ordinary) package
	// - inside the foo.mod/bar [foo.mod/bar.test] test variant package
	// - from the foo.mod/bar_test [foo.mod/bar.test] x_test package
	// - from the foo.mod/foo package
	{"Blah", []string{"bar/bar.go:3", "bar/bar_test.go:7", "bar/bar_x_test.go:12", "foo/foo.go:12"}},

	// Foo is referenced in bar_x_test.go via the intermediate test variant
	// foo.mod/foo [foo.mod/bar.test].
	{"Foo", []string{"bar/bar_x_test.go:13", "foo/foo.go:5"}},
	}

	for _, test := range refTests {
	loc := env.RegexpSearch("foo/foo.go", test.re)
	refs := env.References(loc)

	got := fileLocations(env, refs)
	if diff := cmp.Diff(test.wantRefs, got); diff != "" {
	t.Errorf("References(%q) returned unexpected diff (-want +got):\n%s", test.re, diff)
	}
	}

	implTests := []struct {
	re string
	wantImpls []string
	}{
	// InterfaceM is implemented both in foo.mod/bar [foo.mod/bar.test] (which
	// doesn't import foo), and in foo.mod/bar_test [foo.mod/bar.test], which
	// imports the test variant of foo.
	{"InterfaceM", []string{"bar/bar_test.go:3", "bar/bar_x_test.go:8"}},

	// A search within the ordinary package to should find implementations
	// (Fer) within the augmented test package.
	{"InterfaceF", []string{"foo/foo_test.go:3"}},
	}

	for _, test := range implTests {
	loc := env.RegexpSearch("foo/foo.go", test.re)
	impls := env.Implementations(loc)

	got := fileLocations(env, impls)
	if diff := cmp.Diff(test.wantImpls, got); diff != "" {
	t.Errorf("Implementations(%q) returned unexpected diff (-want +got):\n%s", test.re, diff)
	}
	}
	})
	}

	// This is a regression test for Issue #56169, in which interface
	// implementations in vendored modules were not found. The actual fix
	// was the same as for #55995; see TestVendoringInvalidatesMetadata.
	func TestImplementationsInVendor(t *testing.T) {
	t.Skip("golang/go#56169: file watching does not capture vendor dirs")

	const proxy = `
	-- other.com/b@v1.0.0/go.mod --
	module other.com/b
	go 1.14

	-- other.com/b@v1.0.0/b.go --
	package b
	type B int
	func (B) F() {}
	`
	const src = `
	-- go.mod --
	module example.com/a
	go 1.14
	require other.com/b v1.0.0

	-- go.sum --
	other.com/b v1.0.0 h1:9WyCKS+BLAMRQM0CegP6zqP2beP+ShTbPaARpNY31II=
	other.com/b v1.0.0/go.mod h1:TgHQFucl04oGT+vrUm/liAzukYHNxCwKNkQZEyn3m9g=

	-- a.go --
	package a
	import "other.com/b"
	type I interface { F() }
	var _ b.B

	`
	WithOptions(
	ProxyFiles(proxy),
	Modes(Default), // fails in 'experimental' mode
	).Run(t, src, func(t testing.T, env Env) {
	// Enable to debug go.sum mismatch, which may appear as
	// "module lookup disabled by GOPROXY=off", confusingly.
	if false {
	env.DumpGoSum(".")
	}

	checkVendor := func(locs []protocol.Location, wantVendor bool) {
	if len(locs) != 1 {
	t.Errorf("got %d locations, want 1", len(locs))
	} else if strings.Contains(string(locs[0].URI), "/vendor/") != wantVendor {
	t.Errorf("got location %s, wantVendor=%t", locs[0], wantVendor)
	}
	}

	env.OpenFile("a.go")
	refLoc := env.RegexpSearch("a.go", "I") // find "I" reference

	// Initially, a.I has one implementation b.B in
	// the module cache, not the vendor tree.
	checkVendor(env.Implementations(refLoc), false)

	// Run 'go mod vendor' outside the editor.
	if err := env.Sandbox.RunGoCommand(env.Ctx, ".", "mod", []string{"vendor"}, nil, true); err != nil {
	t.Fatalf("go mod vendor: %v", err)
	}

	// Synchronize changes to watched files.
	env.Await(env.DoneWithChangeWatchedFiles())

	// Now, b.B is found in the vendor tree.
	checkVendor(env.Implementations(refLoc), true)

	// Delete the vendor tree.
	if err := os.RemoveAll(env.Sandbox.Workdir.AbsPath("vendor")); err != nil {
	t.Fatal(err)
	}
	// Notify the server of the deletion.
	if err := env.Sandbox.Workdir.CheckForFileChanges(env.Ctx); err != nil {
	t.Fatal(err)
	}

	// Synchronize again.
	env.Await(env.DoneWithChangeWatchedFiles())

	// b.B is once again defined in the module cache.
	checkVendor(env.Implementations(refLoc), false)
	})
	}

	// This test can't be expressed as a marker test because the marker
	// test framework opens all files (which is a bit of a hack), creating
	// a <command-line-arguments> package for packages that otherwise
	// wouldn't be found from the go.work file.
	func TestReferencesFromWorkspacePackages59674(t *testing.T) {
	testenv.NeedsGo1Point(t, 18) // for go.work support
	const src = `
	-- a/go.mod --
	module example.com/a
	go 1.12

	-- b/go.mod --
	module example.com/b
	go 1.12

	-- c/go.mod --
	module example.com/c
	go 1.12

	-- lib/go.mod --
	module example.com/lib
	go 1.12

	-- go.work --
	use ./a
	use ./b
	// don't use ./c
	use ./lib

	-- a/a.go --
	package a

	import "example.com/lib"

	var _ = lib.F // query here

	-- b/b.go --
	package b

	import "example.com/lib"

	var _ = lib.F // also found by references

	-- c/c.go --
	package c

	import "example.com/lib"

	var _ = lib.F // this reference should not be reported

	-- lib/lib.go --
	package lib

	func F() {} // declaration
	`
	Run(t, src, func(t testing.T, env Env) {
	env.OpenFile("a/a.go")
	refLoc := env.RegexpSearch("a/a.go", "F")
	got := fileLocations(env, env.References(refLoc))
	want := []string{"a/a.go:5", "b/b.go:5", "lib/lib.go:3"}
	if diff := cmp.Diff(want, got); diff != "" {
	t.Errorf("incorrect References (-want +got):\n%s", diff)
	}
	})
	}

	// Test an 'implementation' query on a type that implements 'error'.
	// (Unfortunately builtin locations cannot be expressed using @loc
	// in the marker test framework.)
	func TestImplementationsOfError(t *testing.T) {
	const src = `
	-- go.mod --
	module example.com
	go 1.12

	-- a.go --
	package a

	type Error2 interface {
	Error() string
	}

	type MyError int
	func (MyError) Error() string { return "" }

	type MyErrorPtr int
	func (*MyErrorPtr) Error() string { return "" }
	`
	Run(t, src, func(t testing.T, env Env) {
	env.OpenFile("a.go")

	for _, test := range []struct {
	re string
	want []string
	}{
	// error type
	{"Error2", []string{"a.go:10", "a.go:7", "std:builtin/builtin.go"}},
	{"MyError", []string{"a.go:3", "std:builtin/builtin.go"}},
	{"MyErrorPtr", []string{"a.go:3", "std:builtin/builtin.go"}},
	// error.Error method
	{"(Error).. string", []string{"a.go:11", "a.go:8", "std:builtin/builtin.go"}},
	{"MyError. (Error)", []string{"a.go:4", "std:builtin/builtin.go"}},
	{"MyErrorPtr. (Error)", []string{"a.go:4", "std:builtin/builtin.go"}},
	} {
	matchLoc := env.RegexpSearch("a.go", test.re)
	impls := env.Implementations(matchLoc)
	got := fileLocations(env, impls)
	if !reflect.DeepEqual(got, test.want) {
	t.Errorf("Implementations(%q) = %q, want %q",
	test.re, got, test.want)
	}
	}
	})
	}

	// fileLocations returns a new sorted array of the
	// relative file name and line number of each location.
	// Duplicates are not removed.
	// Standard library filenames are abstracted for robustness.
	func fileLocations(env *regtest.Env, locs []protocol.Location) []string {
	got := make([]string, 0, len(locs))
	for _, loc := range locs {
	path := env.Sandbox.Workdir.URIToPath(loc.URI) // (slashified)
	if i := strings.Index(path, "/src/"); i >= 0 && filepath.IsAbs(path) {
	// Absolute path with "src" segment: assume it's in GOROOT.
	// Strip directory and don't add line/column since they are fragile.
	path = "std:" + path[i+len("/src/"):]
	} else {
	path = fmt.Sprintf("%s:%d", path, loc.Range.Start.Line+1)
	}
	got = append(got, path)
	}
	sort.Strings(got)
	return got
	}