cmd: go get golang.org/x/tools@d88ec18 && go mod vendor

This brings in CL 261725, which applies the vet buildtag checker
to ignored files.

For #41184.

Change-Id: I5f241db5a71fa84d0af0b9e9f8a75ff5bb3dd116
Reviewed-on: https://go-review.googlesource.com/c/go/+/261958
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Jay Conrod <jayconrod@google.com>

src/cmd/go.mod

@@ -9,5 +9,5 @@ require (
 	golang.org/x/crypto v0.0.0-20200820211705-5c72a883971a
 	golang.org/x/mod v0.3.1-0.20200828183125-ce943fd02449
 	golang.org/x/sys v0.0.0-20200923182605-d9f96fdee20d // indirect
-	golang.org/x/tools v0.0.0-20200918232735-d647fc253266
+	golang.org/x/tools v0.0.0-20201013174405-d88ec18c69c7
 )

src/cmd/go.sum

@@ -30,8 +30,8 @@ golang.org/x/sys v0.0.0-20200923182605-d9f96fdee20d h1:L/IKR6COd7ubZrs2oTnTi73Ih
 golang.org/x/sys v0.0.0-20200923182605-d9f96fdee20d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20200918232735-d647fc253266 h1:k7tVuG0g1JwmD3Jh8oAl1vQ1C3jb4Hi/dUl1wWDBJpQ=
+golang.org/x/tools v0.0.0-20201013174405-d88ec18c69c7 h1:z+ozLsKwDztt1oIueYsv07oF+mXNYIiwU0PQVXwmhlo=
-golang.org/x/tools v0.0.0-20200918232735-d647fc253266/go.mod h1:z6u4i615ZeAfBE4XtMziQW1fSVJXACjjbWkB/mvPzlU=
+golang.org/x/tools v0.0.0-20201013174405-d88ec18c69c7/go.mod h1:z6u4i615ZeAfBE4XtMziQW1fSVJXACjjbWkB/mvPzlU=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 h1:go1bK/D/BFZV2I8cIQd1NKEZ+0owSTG1fDTci4IqFcE=

src/cmd/vendor/golang.org/x/tools/go/analysis/analysis.go

@@ -98,6 +98,7 @@ type Pass struct {
 	Fset         *token.FileSet // file position information
 	Files        []*ast.File    // the abstract syntax tree of each file
 	OtherFiles   []string       // names of non-Go files of this package
+	IgnoredFiles []string       // names of ignored source files in this package
 	Pkg          *types.Package // type information about the package
 	TypesInfo    *types.Info    // type information about the syntax trees
 	TypesSizes   types.Sizes    // function for computing sizes of types

src/cmd/vendor/golang.org/x/tools/go/analysis/doc.go

@@ -124,6 +124,7 @@ reporting diagnostics and other information back to the driver.
 		Fset         *token.FileSet
 		Files        []*ast.File
 		OtherFiles   []string
+		IgnoredFiles []string
 		Pkg          *types.Package
 		TypesInfo    *types.Info
 		ResultOf     map[*Analyzer]interface{}
@@ -139,6 +140,12 @@ files such as assembly that are part of this package. See the "asmdecl"
 or "buildtags" analyzers for examples of loading non-Go files and reporting
 diagnostics against them.
 
+The IgnoredFiles field provides the names, but not the contents,
+of ignored Go and non-Go source files that are not part of this package
+with the current build configuration but may be part of other build
+configurations. See the "buildtags" analyzer for an example of loading
+and checking IgnoredFiles.
+
 The ResultOf field provides the results computed by the analyzers
 required by this one, as expressed in its Analyzer.Requires field. The
 driver runs the required analyzers first and makes their results

src/cmd/vendor/golang.org/x/tools/go/analysis/passes/buildtag/buildtag.go

@@ -9,6 +9,7 @@ import (
 	"bytes"
 	"fmt"
 	"go/ast"
+	"go/parser"
 	"strings"
 	"unicode"
 
@@ -33,6 +34,20 @@ func runBuildTag(pass *analysis.Pass) (interface{}, error) {
 			return nil, err
 		}
 	}
+	for _, name := range pass.IgnoredFiles {
+		if strings.HasSuffix(name, ".go") {
+			f, err := parser.ParseFile(pass.Fset, name, nil, parser.ParseComments)
+			if err != nil {
+				// Not valid Go source code - not our job to diagnose, so ignore.
+				return nil, nil
+			}
+			checkGoFile(pass, f)
+		} else {
+			if err := checkOtherFile(pass, name); err != nil {
+				return nil, err
+			}
+		}
+	}
 	return nil, nil
 }
 
@@ -132,13 +147,6 @@ func checkLine(line string, pastCutoff bool) error {
 }
 
 func checkArguments(fields []string) error {
-	// The original version of this checker in vet could examine
-	// files with malformed build tags that would cause the file to
-	// be always ignored by "go build". However, drivers for the new
-	// analysis API will analyze only the files selected to form a
-	// package, so these checks will never fire.
-	// TODO(adonovan): rethink this.
-
 	for _, arg := range fields[1:] {
 		for _, elem := range strings.Split(arg, ",") {
 			if strings.HasPrefix(elem, "!!") {

src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go

@@ -63,6 +63,7 @@ type Config struct {
 	ImportPath                string
 	GoFiles                   []string
 	NonGoFiles                []string
+	IgnoredFiles              []string
 	ImportMap                 map[string]string
 	PackageFile               map[string]string
 	Standard                  map[string]bool
@@ -333,6 +334,7 @@ func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]re
 				Fset:              fset,
 				Files:             files,
 				OtherFiles:        cfg.NonGoFiles,
+				IgnoredFiles:      cfg.IgnoredFiles,
 				Pkg:               pkg,
 				TypesInfo:         info,
 				TypesSizes:        tc.Sizes,

src/cmd/vendor/modules.txt

@@ -45,7 +45,7 @@ golang.org/x/mod/zip
 golang.org/x/sys/internal/unsafeheader
 golang.org/x/sys/unix
 golang.org/x/sys/windows
-# golang.org/x/tools v0.0.0-20200918232735-d647fc253266
+# golang.org/x/tools v0.0.0-20201013174405-d88ec18c69c7
 ## explicit
 golang.org/x/tools/go/analysis
 golang.org/x/tools/go/analysis/internal/analysisflags