gopls/internal/lsp: tolerate new 'imported and not used' error message

Tolerate the new form of the "... imported but not used" error message,
to allow landing this change in go/types.

Along the way, improve the test output when comparing diagnostics, and
formatting results.

For golang/go#54845

Change-Id: I998d539f82e0f70c85bdb4c40858be5e01dd08b6
Reviewed-on: https://go-review.googlesource.com/c/tools/+/435355
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Reviewed-by: Robert Griesemer <gri@google.com>
Auto-Submit: Robert Findley <rfindley@google.com>

gopls/internal/lsp/analysis/undeclaredname/undeclared.go

@@ -45,6 +45,7 @@ var Analyzer = &analysis.Analyzer{
 	RunDespiteErrors: true,
 }
 
+// The prefix for this error message changed in Go 1.20.
 var undeclaredNamePrefixes = []string{"undeclared name: ", "undefined: "}
 
 func run(pass *analysis.Pass) (interface{}, error) {

gopls/internal/lsp/analysis/unusedvariable/testdata/src/assign/a.go

@@ -14,55 +14,55 @@ type A struct {
 }
 
 func singleAssignment() {
-	v := "s" // want `v declared but not used`
+	v := "s" // want `v declared (and|but) not used`
 
-	s := []int{ // want `s declared but not used`
+	s := []int{ // want `s declared (and|but) not used`
 		1,
 		2,
 	}
 
-	a := func(s string) bool { // want `a declared but not used`
+	a := func(s string) bool { // want `a declared (and|but) not used`
 		return false
 	}
 
 	if 1 == 1 {
-		s := "v" // want `s declared but not used`
+		s := "v" // want `s declared (and|but) not used`
 	}
 
 	panic("I should survive")
 }
 
 func noOtherStmtsInBlock() {
-	v := "s" // want `v declared but not used`
+	v := "s" // want `v declared (and|but) not used`
 }
 
 func partOfMultiAssignment() {
-	f, err := os.Open("file") // want `f declared but not used`
+	f, err := os.Open("file") // want `f declared (and|but) not used`
 	panic(err)
 }
 
 func sideEffects(cBool chan bool, cInt chan int) {
-	b := <-c            // want `b declared but not used`
-	s := fmt.Sprint("") // want `s declared but not used`
-	a := A{             // want `a declared but not used`
+	b := <-c            // want `b declared (and|but) not used`
+	s := fmt.Sprint("") // want `s declared (and|but) not used`
+	a := A{             // want `a declared (and|but) not used`
 		b: func() int {
 			return 1
 		}(),
 	}
-	c := A{<-cInt}          // want `c declared but not used`
-	d := fInt() + <-cInt    // want `d declared but not used`
-	e := fBool() && <-cBool // want `e declared but not used`
-	f := map[int]int{       // want `f declared but not used`
+	c := A{<-cInt}          // want `c declared (and|but) not used`
+	d := fInt() + <-cInt    // want `d declared (and|but) not used`
+	e := fBool() && <-cBool // want `e declared (and|but) not used`
+	f := map[int]int{       // want `f declared (and|but) not used`
 		fInt(): <-cInt,
 	}
-	g := []int{<-cInt}       // want `g declared but not used`
-	h := func(s string) {}   // want `h declared but not used`
-	i := func(s string) {}() // want `i declared but not used`
+	g := []int{<-cInt}       // want `g declared (and|but) not used`
+	h := func(s string) {}   // want `h declared (and|but) not used`
+	i := func(s string) {}() // want `i declared (and|but) not used`
 }
 
 func commentAbove() {
 	// v is a variable
-	v := "s" // want `v declared but not used`
+	v := "s" // want `v declared (and|but) not used`
 }
 
 func fBool() bool {

gopls/internal/lsp/analysis/unusedvariable/testdata/src/assign/a.go.golden

@@ -24,26 +24,26 @@ func noOtherStmtsInBlock() {
 }
 
 func partOfMultiAssignment() {
-	_, err := os.Open("file") // want `f declared but not used`
+	_, err := os.Open("file") // want `f declared (and|but) not used`
 	panic(err)
 }
 
 func sideEffects(cBool chan bool, cInt chan int) {
-	<-c            // want `b declared but not used`
-	fmt.Sprint("") // want `s declared but not used`
-	A{             // want `a declared but not used`
+	<-c            // want `b declared (and|but) not used`
+	fmt.Sprint("") // want `s declared (and|but) not used`
+	A{             // want `a declared (and|but) not used`
 		b: func() int {
 			return 1
 		}(),
 	}
-	A{<-cInt}          // want `c declared but not used`
-	fInt() + <-cInt    // want `d declared but not used`
-	fBool() && <-cBool // want `e declared but not used`
-	map[int]int{       // want `f declared but not used`
+	A{<-cInt}          // want `c declared (and|but) not used`
+	fInt() + <-cInt    // want `d declared (and|but) not used`
+	fBool() && <-cBool // want `e declared (and|but) not used`
+	map[int]int{       // want `f declared (and|but) not used`
 		fInt(): <-cInt,
 	}
-	[]int{<-cInt}       // want `g declared but not used`
-	func(s string) {}() // want `i declared but not used`
+	[]int{<-cInt}       // want `g declared (and|but) not used`
+	func(s string) {}() // want `i declared (and|but) not used`
 }
 
 func commentAbove() {

gopls/internal/lsp/analysis/unusedvariable/testdata/src/decl/a.go

@@ -5,25 +5,25 @@
 package decl
 
 func a() {
-	var b, c bool // want `b declared but not used`
+	var b, c bool // want `b declared (and|but) not used`
 	panic(c)
 
 	if 1 == 1 {
-		var s string // want `s declared but not used`
+		var s string // want `s declared (and|but) not used`
 	}
 }
 
 func b() {
 	// b is a variable
-	var b bool // want `b declared but not used`
+	var b bool // want `b declared (and|but) not used`
 }
 
 func c() {
 	var (
 		d string
 
 		// some comment for c
-		c bool // want `c declared but not used`
+		c bool // want `c declared (and|but) not used`
 	)
 
 	panic(d)

gopls/internal/lsp/analysis/unusedvariable/testdata/src/decl/a.go.golden

@@ -5,7 +5,7 @@
 package decl
 
 func a() {
-	var c bool // want `b declared but not used`
+	var c bool // want `b declared (and|but) not used`
 	panic(c)
 
 	if 1 == 1 {

gopls/internal/lsp/analysis/unusedvariable/unusedvariable.go

@@ -34,15 +34,18 @@ var Analyzer = &analysis.Analyzer{
 
 type fixesForError map[types.Error][]analysis.SuggestedFix
 
-const unusedVariableSuffix = " declared but not used"
+// The suffix for this error message changed in Go 1.20.
+var unusedVariableSuffixes = []string{" declared and not used", " declared but not used"}
 
 func run(pass *analysis.Pass) (interface{}, error) {
 	for _, typeErr := range analysisinternal.GetTypeErrors(pass) {
-		if strings.HasSuffix(typeErr.Msg, unusedVariableSuffix) {
-			varName := strings.TrimSuffix(typeErr.Msg, unusedVariableSuffix)
-			err := runForError(pass, typeErr, varName)
-			if err != nil {
-				return nil, err
+		for _, suffix := range unusedVariableSuffixes {
+			if strings.HasSuffix(typeErr.Msg, suffix) {
+				varName := strings.TrimSuffix(typeErr.Msg, suffix)
+				err := runForError(pass, typeErr, varName)
+				if err != nil {
+					return nil, err
+				}
 			}
 		}
 	}

gopls/internal/lsp/cmd/test/check.go

@@ -59,7 +59,5 @@ func (r *runner) Diagnostics(t *testing.T, uri span.URI, want []*source.Diagnost
 		diag.Severity = 0
 	}
 
-	if diff := tests.DiffDiagnostics(uri, want, got); diff != "" {
-		t.Error(diff)
-	}
+	tests.CompareDiagnostics(t, uri, want, got)
 }

gopls/internal/lsp/lsp_test.go

@@ -223,9 +223,7 @@ func (r *runner) Diagnostics(t *testing.T, uri span.URI, want []*source.Diagnost
 	v := r.server.session.View(r.data.Config.Dir)
 	r.collectDiagnostics(v)
 	got := append([]*source.Diagnostic(nil), r.diagnostics[uri]...) // copy
-	if diff := tests.DiffDiagnostics(uri, want, got); diff != "" {
-		t.Error(diff)
-	}
+	tests.CompareDiagnostics(t, uri, want, got)
 }
 
 func (r *runner) FoldingRanges(t *testing.T, spn span.Span) {
@@ -416,8 +414,8 @@ func (r *runner) Format(t *testing.T, spn span.Span) {
 		t.Error(err)
 	}
 	got := diff.ApplyEdits(string(m.Content), sedits)
-	if gofmted != got {
-		t.Errorf("format failed for %s, expected:\n%v\ngot:\n%v", filename, gofmted, got)
+	if diff := compare.Text(gofmted, got); diff != "" {
+		t.Errorf("format failed for %s (-want +got):\n%s", filename, diff)
 	}
 }
 

gopls/internal/lsp/source/source_test.go

@@ -156,9 +156,7 @@ func (r *runner) Diagnostics(t *testing.T, uri span.URI, want []*source.Diagnost
 	if err != nil {
 		t.Fatal(err)
 	}
-	if diff := tests.DiffDiagnostics(fileID.URI, want, got); diff != "" {
-		t.Error(diff)
-	}
+	tests.CompareDiagnostics(t, fileID.URI, want, got)
 }
 
 func (r *runner) Completion(t *testing.T, src span.Span, test tests.Completion, items tests.CompletionItems) {

gopls/internal/lsp/testdata/bad/bad0.go

@@ -9,7 +9,7 @@ func stuff() { //@item(stuff, "stuff", "func()", "func")
 	x := "heeeeyyyy"
 	random2(x) //@diag("x", "compiler", "cannot use x \\(variable of type string\\) as int value in argument to random2", "error")
 	random2(1) //@complete("dom", random, random2, random3)
-	y := 3     //@diag("y", "compiler", "y declared but not used", "error")
+	y := 3     //@diag("y", "compiler", "y declared (and|but) not used", "error")
 }
 
 type bob struct { //@item(bob, "bob", "struct{...}", "struct")

gopls/internal/lsp/testdata/bad/bad1.go

@@ -14,9 +14,9 @@ func random() int { //@item(random, "random", "func() int", "func")
 }
 
 func random2(y int) int { //@item(random2, "random2", "func(y int) int", "func"),item(bad_y_param, "y", "int", "var")
-	x := 6       //@item(x, "x", "int", "var"),diag("x", "compiler", "x declared but not used", "error")
-	var q blah   //@item(q, "q", "blah", "var"),diag("q", "compiler", "q declared but not used", "error"),diag("blah", "compiler", "(undeclared name|undefined): blah", "error")
-	var t **blob //@item(t, "t", "**blob", "var"),diag("t", "compiler", "t declared but not used", "error"),diag("blob", "compiler", "(undeclared name|undefined): blob", "error")
+	x := 6       //@item(x, "x", "int", "var"),diag("x", "compiler", "x declared (and|but) not used", "error")
+	var q blah   //@item(q, "q", "blah", "var"),diag("q", "compiler", "q declared (and|but) not used", "error"),diag("blah", "compiler", "(undeclared name|undefined): blah", "error")
+	var t **blob //@item(t, "t", "**blob", "var"),diag("t", "compiler", "t declared (and|but) not used", "error"),diag("blob", "compiler", "(undeclared name|undefined): blob", "error")
 	//@complete("", q, t, x, bad_y_param, global_a, bob, random, random2, random3, stateFunc, stuff)
 
 	return y
@@ -25,10 +25,10 @@ func random2(y int) int { //@item(random2, "random2", "func(y int) int", "func")
 func random3(y ...int) { //@item(random3, "random3", "func(y ...int)", "func"),item(y_variadic_param, "y", "[]int", "var")
 	//@complete("", y_variadic_param, global_a, bob, random, random2, random3, stateFunc, stuff)
 
-	var ch chan (favType1)   //@item(ch, "ch", "chan (favType1)", "var"),diag("ch", "compiler", "ch declared but not used", "error"),diag("favType1", "compiler", "(undeclared name|undefined): favType1", "error")
-	var m map[keyType]int    //@item(m, "m", "map[keyType]int", "var"),diag("m", "compiler", "m declared but not used", "error"),diag("keyType", "compiler", "(undeclared name|undefined): keyType", "error")
-	var arr []favType2       //@item(arr, "arr", "[]favType2", "var"),diag("arr", "compiler", "arr declared but not used", "error"),diag("favType2", "compiler", "(undeclared name|undefined): favType2", "error")
-	var fn1 func() badResult //@item(fn1, "fn1", "func() badResult", "var"),diag("fn1", "compiler", "fn1 declared but not used", "error"),diag("badResult", "compiler", "(undeclared name|undefined): badResult", "error")
-	var fn2 func(badParam)   //@item(fn2, "fn2", "func(badParam)", "var"),diag("fn2", "compiler", "fn2 declared but not used", "error"),diag("badParam", "compiler", "(undeclared name|undefined): badParam", "error")
+	var ch chan (favType1)   //@item(ch, "ch", "chan (favType1)", "var"),diag("ch", "compiler", "ch declared (and|but) not used", "error"),diag("favType1", "compiler", "(undeclared name|undefined): favType1", "error")
+	var m map[keyType]int    //@item(m, "m", "map[keyType]int", "var"),diag("m", "compiler", "m declared (and|but) not used", "error"),diag("keyType", "compiler", "(undeclared name|undefined): keyType", "error")
+	var arr []favType2       //@item(arr, "arr", "[]favType2", "var"),diag("arr", "compiler", "arr declared (and|but) not used", "error"),diag("favType2", "compiler", "(undeclared name|undefined): favType2", "error")
+	var fn1 func() badResult //@item(fn1, "fn1", "func() badResult", "var"),diag("fn1", "compiler", "fn1 declared (and|but) not used", "error"),diag("badResult", "compiler", "(undeclared name|undefined): badResult", "error")
+	var fn2 func(badParam)   //@item(fn2, "fn2", "func(badParam)", "var"),diag("fn2", "compiler", "fn2 declared (and|but) not used", "error"),diag("badParam", "compiler", "(undeclared name|undefined): badParam", "error")
 	//@complete("", arr, ch, fn1, fn2, m, y_variadic_param, global_a, bob, random, random2, random3, stateFunc, stuff)
 }

gopls/internal/lsp/testdata/format/bad_format.go.golden

@@ -9,7 +9,7 @@ import (
 
 func hello() {
 
-	var x int //@diag("x", "compiler", "x declared but not used", "error")
+	var x int //@diag("x", "compiler", "x declared (and|but) not used", "error")
 }
 
 func hi() {

gopls/internal/lsp/testdata/format/bad_format.go.in

@@ -11,7 +11,7 @@ func hello() {
 
 
 
-	var x int //@diag("x", "compiler", "x declared but not used", "error")
+	var x int //@diag("x", "compiler", "x declared (and|but) not used", "error")
 }
 
 func hi() {

gopls/internal/lsp/testdata/generated/generator.go

@@ -1,5 +1,5 @@
 package generated
 
 func _() {
-	var x int //@diag("x", "compiler", "x declared but not used", "error")
+	var x int //@diag("x", "compiler", "x declared (and|but) not used", "error")
 }

gopls/internal/lsp/testdata/testy/testy_test.go

@@ -8,7 +8,7 @@ import (
 )
 
 func TestSomething(t *testing.T) { //@item(TestSomething, "TestSomething(t *testing.T)", "", "func")
-	var x int //@mark(testyX, "x"),diag("x", "compiler", "x declared but not used", "error"),refs("x", testyX)
+	var x int //@mark(testyX, "x"),diag("x", "compiler", "x declared (and|but) not used", "error"),refs("x", testyX)
 	a()       //@mark(testyA, "a")
 }