From fccaf8c467f785e42fa30f4650b98fd0a1c6df6e Mon Sep 17 00:00:00 2001
From: Robert Griesemer <gri@golang.org>
Date: Tue, 4 Mar 2014 14:32:55 -0800
Subject: [PATCH] go.tools/go/types: adjust tests for better parser error
 positions

The parser may return error positions referring to positions
immediately after rather than at a token position. Provide
mechanism to identify those positions in test cases.

Also: Don't compute position strings for each token in test
cases. Should speed up Check test.

Pending CL 70190046 in main repo.

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/71330043
---
 go/types/check_test.go      | 27 +++++++++++++++++++++------
 go/types/testdata/stmt0.src |  4 ++--
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/go/types/check_test.go b/go/types/check_test.go
index 0d0afce8..da21986f 100644
--- a/go/types/check_test.go
+++ b/go/types/check_test.go
@@ -122,9 +122,11 @@ func parseFiles(t *testing.T, filenames []string) ([]*ast.File, []error) {
 
 // ERROR comments must start with text `ERROR "rx"` or `ERROR rx` where
 // rx is a regular expression that matches the expected error message.
-// Space around "rx" or rx is ignored.
+// Space around "rx" or rx is ignored. Use the form `ERROR HERE "rx"`
+// for error messages that are located immediately after rather than
+// at a token's position.
 //
-var errRx = regexp.MustCompile(`^ *ERROR *"?([^"]*)"?`)
+var errRx = regexp.MustCompile(`^ *ERROR *(HERE)? *"?([^"]*)"?`)
 
 // errMap collects the regular expressions of ERROR comments found
 // in files and returns them as a map of error positions to error messages.
@@ -142,7 +144,8 @@ func errMap(t *testing.T, testname string, files []*ast.File) map[string][]strin
 
 		var s scanner.Scanner
 		s.Init(fset.AddFile(filename, -1, len(src)), src, nil, scanner.ScanComments)
-		var prev string // position string of last non-comment, non-semicolon token
+		var prev token.Pos // position of last non-comment, non-semicolon token
+		var here token.Pos // position immediately after the token at position prev
 
 	scanFile:
 		for {
@@ -154,8 +157,13 @@ func errMap(t *testing.T, testname string, files []*ast.File) map[string][]strin
 				if lit[1] == '*' {
 					lit = lit[:len(lit)-2] // strip trailing */
 				}
-				if s := errRx.FindStringSubmatch(lit[2:]); len(s) == 2 {
-					errmap[prev] = append(errmap[prev], strings.TrimSpace(s[1]))
+				if s := errRx.FindStringSubmatch(lit[2:]); len(s) == 3 {
+					pos := prev
+					if s[1] == "HERE" {
+						pos = here
+					}
+					p := fset.Position(pos).String()
+					errmap[p] = append(errmap[p], strings.TrimSpace(s[2]))
 				}
 			case token.SEMICOLON:
 				// ignore automatically inserted semicolon
@@ -164,7 +172,14 @@ func errMap(t *testing.T, testname string, files []*ast.File) map[string][]strin
 				}
 				fallthrough
 			default:
-				prev = fset.Position(pos).String()
+				prev = pos
+				var l int // token length
+				if tok.IsLiteral() {
+					l = len(lit)
+				} else {
+					l = len(tok.String())
+				}
+				here = prev + token.Pos(l)
 			}
 		}
 	}
diff --git a/go/types/testdata/stmt0.src b/go/types/testdata/stmt0.src
index 6b6349b2..c42bd36a 100644
--- a/go/types/testdata/stmt0.src
+++ b/go/types/testdata/stmt0.src
@@ -213,7 +213,7 @@ func selects() {
 }
 
 func gos() {
-	go 1 /* ERROR "expected function/method call" */
+	go 1 /* ERROR HERE "function must be invoked" */
 	go int /* ERROR "go requires function call, not conversion" */ (0)
 	go gos()
 	var c chan int
@@ -222,7 +222,7 @@ func gos() {
 }
 
 func defers() {
-	defer 1 /* ERROR "expected function/method call" */
+	defer 1 /* ERROR HERE "function must be invoked" */
 	defer int /* ERROR "defer requires function call, not conversion" */ (0)
 	defer defers()
 	var c chan int