all: update vendored x/tools

Pull in the following x/tools changes:

- CL 732260: go/analysis/passes/modernize: disable BLoop analyzer
- CL 733340: gopls/internal/analysis/modernize: mapsloop: undefined loop-var

For #74967.
For #77008.

[git-generate]
go install golang.org/x/build/cmd/updatestd@latest
go install golang.org/x/tools/cmd/bundle@latest
updatestd -goroot=$(pwd) -branch=internal-branch.go1.26-vendor

Change-Id: Ic0c10569a4a3a292aec9164e6dd034e55d052904
Reviewed-on: https://go-review.googlesource.com/c/go/+/733780
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>

6 files changed, 27 insertions, 6 deletions

diff --git a/src/cmd/go.mod b/src/cmd/go.mod
index c7d3cc6136..85e8c4cb5f 100644
--- a/src/cmd/go.mod
+++ b/src/cmd/go.mod
@@ -11,7 +11,7 @@ require (
 	golang.org/x/sys v0.39.0
 	golang.org/x/telemetry v0.0.0-20251128220624-abf20d0e57ec
 	golang.org/x/term v0.38.0
-	golang.org/x/tools v0.39.1-0.20251205000126-062ef7b6ced2
+	golang.org/x/tools v0.39.1-0.20251230210517-d44be789a05c
 )
 
 require (
diff --git a/src/cmd/go.sum b/src/cmd/go.sum
index b02c469a41..61c88e5253 100644
--- a/src/cmd/go.sum
+++ b/src/cmd/go.sum
@@ -22,7 +22,7 @@ golang.org/x/term v0.38.0 h1:PQ5pkm/rLO6HnxFR7N2lJHOZX6Kez5Y1gDSJla6jo7Q=
 golang.org/x/term v0.38.0/go.mod h1:bSEAKrOT1W+VSu9TSCMtoGEOUcKxOKgl3LE5QEF/xVg=
 golang.org/x/text v0.32.0 h1:ZD01bjUt1FQ9WJ0ClOL5vxgxOI/sVCNgX1YtKwcY0mU=
 golang.org/x/text v0.32.0/go.mod h1:o/rUWzghvpD5TXrTIBuJU77MTaN0ljMWE47kxGJQ7jY=
-golang.org/x/tools v0.39.1-0.20251205000126-062ef7b6ced2 h1:2Qqv605Nus9iUp3ErvEU/q92Q3HAzeROztzl9pzAno8=
-golang.org/x/tools v0.39.1-0.20251205000126-062ef7b6ced2/go.mod h1:JnefbkDPyD8UU2kI5fuf8ZX4/yUeh9W877ZeBONxUqQ=
+golang.org/x/tools v0.39.1-0.20251230210517-d44be789a05c h1:0pZej6BQOooNbOfjJEu4v5qx9hdwFX8HnvHCcNXcs2w=
+golang.org/x/tools v0.39.1-0.20251230210517-d44be789a05c/go.mod h1:JnefbkDPyD8UU2kI5fuf8ZX4/yUeh9W877ZeBONxUqQ=
 rsc.io/markdown v0.0.0-20240306144322-0bf8f97ee8ef h1:mqLYrXCXYEZOop9/Dbo6RPX11539nwiCNBb1icVPmw8=
 rsc.io/markdown v0.0.0-20240306144322-0bf8f97ee8ef/go.mod h1:8xcPgWmwlZONN1D9bjxtHEjrUtSEa3fakVF8iaewYKQ=
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
index 45aed7909c..f1202c7a11 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/doc.go
@@ -80,6 +80,8 @@ or b.ResetTimer within the same function will also be removed.
 Caveats: The b.Loop() method is designed to prevent the compiler from
 optimizing away the benchmark loop, which can occasionally result in
 slower execution due to increased allocations in some specific cases.
+Since its fix may change the performance of nanosecond-scale benchmarks,
+bloop is disabled by default in the `go fix` analyzer suite; see golang/go#74967.
 
 # Analyzer any
 
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
index f97541d4b3..795f5b6c6b 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/maps.go
@@ -231,9 +231,28 @@ func mapsloop(pass *analysis.Pass) (any, error) {
 				// Have: for k, v := range x { lhs = rhs }
 
 				assign := rng.Body.List[0].(*ast.AssignStmt)
+
+				// usesKV reports whether e references vars k or v.
+				usesKV := func(e ast.Expr) bool {
+					k := info.Defs[rng.Key.(*ast.Ident)]
+					v := info.Defs[rng.Value.(*ast.Ident)]
+					for n := range ast.Preorder(e) {
+						if id, ok := n.(*ast.Ident); ok {
+							obj := info.Uses[id]
+							if obj != nil && // don't rely on k, v being non-nil
+								(obj == k || obj == v) {
+								return true
+							}
+						}
+					}
+					return false
+				}
+
 				if index, ok := assign.Lhs[0].(*ast.IndexExpr); ok &&
+					len(assign.Lhs) == 1 &&
 					astutil.EqualSyntax(rng.Key, index.Index) &&
-					astutil.EqualSyntax(rng.Value, assign.Rhs[0]) {
+					astutil.EqualSyntax(rng.Value, assign.Rhs[0]) &&
+					!usesKV(index.X) { // reject (e.g.) f(k, v)[k] = v
 					if tmap, ok := typeparams.CoreType(info.TypeOf(index.X)).(*types.Map); ok &&
 						types.Identical(info.TypeOf(index), info.TypeOf(rng.Value)) && // m[k], v
 						types.Identical(tmap.Key(), info.TypeOf(rng.Key)) {
diff --git a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
index 013ce79d6c..f09a2d26ca 100644
--- a/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
+++ b/src/cmd/vendor/golang.org/x/tools/go/analysis/passes/modernize/modernize.go
@@ -34,7 +34,7 @@ var doc string
 var Suite = []*analysis.Analyzer{
 	AnyAnalyzer,
 	// AppendClippedAnalyzer, // not nil-preserving!
-	BLoopAnalyzer,
+	// BLoopAnalyzer, // may skew benchmark results, see golang/go#74967
 	FmtAppendfAnalyzer,
 	ForVarAnalyzer,
 	MapsLoopAnalyzer,
diff --git a/src/cmd/vendor/modules.txt b/src/cmd/vendor/modules.txt
index 7c122cd9d1..9c179c4bcd 100644
--- a/src/cmd/vendor/modules.txt
+++ b/src/cmd/vendor/modules.txt
@@ -73,7 +73,7 @@ golang.org/x/text/internal/tag
 golang.org/x/text/language
 golang.org/x/text/transform
 golang.org/x/text/unicode/norm
-# golang.org/x/tools v0.39.1-0.20251205000126-062ef7b6ced2
+# golang.org/x/tools v0.39.1-0.20251230210517-d44be789a05c
 ## explicit; go 1.24.0
 golang.org/x/tools/cmd/bisect
 golang.org/x/tools/cover