go/expect: support markers in comments in go/packagestest

This is specifically necessary to test CL 197879.

Change-Id: I2b4bbdd322d52097fc1444242d3e26a3d8ea75e7
Reviewed-on: https://go-review.googlesource.com/c/tools/+/201520
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Cottrell <iancottrell@google.com>

go/expect/expect_test.go

@@ -20,7 +20,7 @@ func TestMarker(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	const expectNotes = 11
+	const expectNotes = 12
 	expectMarkers := map[string]string{
 		"αSimpleMarker": "α",
 		"OffsetMarker":  "β",
@@ -30,6 +30,7 @@ func TestMarker(t *testing.T) {
 		"ηBlockMarker":  "η",
 		"Declared":      "η",
 		"Comment":       "ι",
+		"LineComment":   "someFunc",
 		"NonIdentifier": "+",
 	}
 	expectChecks := map[string][]interface{}{
@@ -129,6 +130,10 @@ func checkMarker(t *testing.T, fset *token.FileSet, readFile expect.ReadFile, ma
 	if start != expectStart {
 		t.Errorf("%v: Expected %v got %v", fset.Position(pos), fset.Position(expectStart), fset.Position(start))
 	}
+	// Don't check the end for the LineComment test.
+	if name == "LineComment" {
+		return
+	}
 	if expectEnd, ok := markers[name+"@"]; ok && end != expectEnd {
 		t.Errorf("%v: Expected end %v got %v", fset.Position(pos), fset.Position(expectEnd), fset.Position(end))
 	}

go/expect/extract.go

@@ -59,11 +59,27 @@ func Extract(fset *token.FileSet, file *ast.File) ([]*Note, error) {
 				text = strings.TrimSuffix(text, "*/")
 			}
 			text = text[2:] // remove "//" or "/*" prefix
+
+			// Allow notes to appear within comments.
+			// For example:
+			// "// //@mark()" is valid.
+			// "// @mark()" is not valid.
+			// "// /*@mark()*/" is not valid.
+			var adjust int
+			if i := strings.Index(text, commentStart); i > 2 {
+				// Get the text before the commentStart.
+				pre := text[i-2 : i]
+				if pre != "//" {
+					continue
+				}
+				text = text[i:]
+				adjust = i
+			}
 			if !strings.HasPrefix(text, commentStart) {
 				continue
 			}
 			text = text[len(commentStart):]
-			parsed, err := parse(fset, c.Pos()+4, text)
+			parsed, err := parse(fset, token.Pos(int(c.Pos())+4+adjust), text)
 			if err != nil {
 				return nil, err
 			}

go/expect/testdata/test.go

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+// Package fake1 is used to test the expect package.
 package fake1
 
 // The greek letters in this file mark points we use for marker tests.
@@ -19,6 +20,7 @@ const (
 
 /*Marker ι inside ι a comment*/ //@mark(Comment,"ι inside ")
 
+// someFunc is a function. //@mark(LineComment, "someFunc")
 func someFunc(a, b int) int {
 	// The line below must be the first occurrence of the plus operator
 	return a + b + 1 //@mark(NonIdentifier, re`\+[^\+]*`)

internal/lsp/testdata/bad/bad1.go

@@ -2,10 +2,6 @@
 
 package bad
 
-// import (
-// 	"github.com/bob/pkg" //@diag("\"github.com/bob/pkg\"", "LSP", "unable to import "\"github.com/bob/pkg\"")
-// )
-
 var a unknown //@item(global_a, "a", "unknown", "var"),diag("unknown", "LSP", "undeclared name: unknown")
 
 func random() int { //@item(random, "random", "func() int", "func")