Merge e693ddf520 into 49cdf0c42e

Fixes #74199

Change-Id: I6a15fbd59a3a3f8c496440f56d09d695e1504e4e
Reviewed-on: https://go-review.googlesource.com/c/go/+/682576
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Alan Donovan <adonovan@google.com>
Auto-Submit: Damien Neil <dneil@google.com>

src/cmd/go/alldocs.go

@@ -1235,6 +1235,8 @@
 // This flag is mainly for tools that understand Go version dependencies.
 // Users should prefer 'go get toolchain@version'.
 //
+// The -droptoolchain flag removes the toolchain directive from the go.mod file.
+//
 // The -exclude=path@version and -dropexclude=path@version flags
 // add and drop an exclusion for the given module path and version.
 // Note that -exclude=path@version is a no-op if that exclusion already exists.
@@ -1264,7 +1266,7 @@
 //
 // The -godebug, -dropgodebug, -require, -droprequire, -exclude, -dropexclude,
 // -replace, -dropreplace, -retract, -dropretract, -tool, -droptool, -ignore,
-// and -dropignore editing flags may be repeated, and the changes are applied
+// -dropignore, and -droptoolchain editing flags may be repeated, and the changes are applied
 // in the order given.
 //
 // The -print flag prints the final go.mod in its text format instead of
@@ -1806,7 +1808,7 @@
 // To view the current telemetry mode, run "go telemetry".
 // To disable telemetry uploading, but keep local data collection, run
 // "go telemetry local".
-// To enable both collection and uploading, run “go telemetry on”.
+// To enable both collection and uploading, run "go telemetry on".
 // To disable both collection and uploading, run "go telemetry off".
 //
 // The current telemetry mode is also available as the value of the

src/cmd/go/internal/modcmd/edit.go

@@ -66,6 +66,8 @@ The -toolchain=version flag sets the Go toolchain to use.
 This flag is mainly for tools that understand Go version dependencies.
 Users should prefer 'go get toolchain@version'.
 
+The -droptoolchain flag removes the toolchain directive from the go.mod file.
+
 The -exclude=path@version and -dropexclude=path@version flags
 add and drop an exclusion for the given module path and version.
 Note that -exclude=path@version is a no-op if that exclusion already exists.
@@ -95,7 +97,7 @@ for the given path.
 
 The -godebug, -dropgodebug, -require, -droprequire, -exclude, -dropexclude,
 -replace, -dropreplace, -retract, -dropretract, -tool, -droptool, -ignore,
-and -dropignore editing flags may be repeated, and the changes are applied
+-dropignore, and -droptoolchain editing flags may be repeated, and the changes are applied
 in the order given.
 
 The -print flag prints the final go.mod in its text format instead of
@@ -169,13 +171,14 @@ See https://golang.org/ref/mod#go-mod-edit for more about 'go mod edit'.
 }
 
 var (
-	editFmt       = cmdEdit.Flag.Bool("fmt", false, "")
-	editGo        = cmdEdit.Flag.String("go", "", "")
-	editToolchain = cmdEdit.Flag.String("toolchain", "", "")
-	editJSON      = cmdEdit.Flag.Bool("json", false, "")
-	editPrint     = cmdEdit.Flag.Bool("print", false, "")
-	editModule    = cmdEdit.Flag.String("module", "", "")
-	edits         []func(*modfile.File) // edits specified in flags
+	editFmt           = cmdEdit.Flag.Bool("fmt", false, "")
+	editGo            = cmdEdit.Flag.String("go", "", "")
+	editToolchain     = cmdEdit.Flag.String("toolchain", "", "")
+	editJSON          = cmdEdit.Flag.Bool("json", false, "")
+	editPrint         = cmdEdit.Flag.Bool("print", false, "")
+	editModule        = cmdEdit.Flag.String("module", "", "")
+	editDropToolchain = cmdEdit.Flag.Bool("droptoolchain", false, "drop the toolchain directive")
+	edits             []func(*modfile.File) // edits specified in flags
 )
 
 type flagFunc func(string)
@@ -213,6 +216,7 @@ func runEdit(ctx context.Context, cmd *base.Command, args []string) {
 		*editJSON ||
 		*editPrint ||
 		*editFmt ||
+		*editDropToolchain ||
 		len(edits) > 0
 
 	if !anyFlags {
@@ -223,6 +227,10 @@ func runEdit(ctx context.Context, cmd *base.Command, args []string) {
 		base.Fatalf("go: cannot use both -json and -print")
 	}
 
+	if *editToolchain != "" && *editDropToolchain {
+		base.Fatalf("go: -toolchain and -droptoolchain are mutually exclusive")
+	}
+
 	if len(args) > 1 {
 		base.Fatalf("go: too many arguments")
 	}
@@ -278,6 +286,9 @@ func runEdit(ctx context.Context, cmd *base.Command, args []string) {
 			base.Fatalf("go: internal error: %v", err)
 		}
 	}
+	if *editDropToolchain {
+		modFile.DropToolchainStmt()
+	}
 
 	if len(edits) > 0 {
 		for _, edit := range edits {

src/cmd/go/testdata/script/mod_edit_droptoolchain.txt

@@ -0,0 +1,35 @@
+# Test for go mod edit -droptoolchain
+
+# Setup
+env GO111MODULE=on
+env GOFLAGS=-mod=mod
+
+# Create a new module
+! exists go.mod
+go mod init example.com/test
+exists go.mod
+
+# Check that the toolchain directive is not present initially
+! grep toolchain go.mod
+
+# Add a toolchain directive
+go mod edit -toolchain=go1.21
+grep 'toolchain go1.21' go.mod
+
+# Remove the toolchain directive using -droptoolchain
+go mod edit -droptoolchain
+! grep toolchain go.mod
+
+# Add a toolchain directive again
+go mod edit -toolchain=go1.22
+grep 'toolchain go1.22' go.mod
+
+# Make sure that -toolchain=none still works as before
+go mod edit -toolchain=none
+! grep toolchain go.mod
+
+# Add a toolchain directive again and use -droptoolchain with an argument (should be ignored)
+go mod edit -toolchain=go1.23
+grep 'toolchain go1.23' go.mod
+go mod edit -droptoolchain
+! grep toolchain go.mod 

src/crypto/cipher/gcm.go

@@ -82,7 +82,7 @@ func newGCM(cipher Block, nonceSize, tagSize int) (AEAD, error) {
 
 // NewGCMWithRandomNonce returns the given cipher wrapped in Galois Counter
 // Mode, with randomly-generated nonces. The cipher must have been created by
-// [aes.NewCipher].
+// [crypto/aes.NewCipher].
 //
 // It generates a random 96-bit nonce, which is prepended to the ciphertext by Seal,
 // and is extracted from the ciphertext by Open. The NonceSize of the AEAD is zero,

src/go/doc/testdata/issue62640.0.golden

@@ -0,0 +1,22 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+

src/go/doc/testdata/issue62640.1.golden

@@ -0,0 +1,22 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+

src/go/doc/testdata/issue62640.2.golden

@@ -0,0 +1,25 @@
+// 
+PACKAGE issue62640
+
+IMPORTPATH
+	testdata/issue62640
+
+FILENAMES
+	testdata/issue62640.go
+
+TYPES
+	// 
+	type E struct{}
+
+	// F should be hidden within S because of the S.F field. 
+	func (E) F()
+
+	// 
+	type S struct {
+		E
+		F	int
+	}
+
+	// F should be hidden within S because of the S.F field. 
+	func (S) F()
+

src/go/doc/testdata/issue62640.go

@@ -0,0 +1,15 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package issue62640
+
+type E struct{}
+
+// F should be hidden within S because of the S.F field.
+func (E) F() {}
+
+type S struct {
+	E
+	F int
+}

src/runtime/mheap.go

@@ -312,8 +312,10 @@ type heapArena struct {
 	// during marking.
 	pageSpecials [pagesPerArena / 8]uint8
 
-	// pageUseSpanDartboard is a bitmap that indicates which spans are
-	// heap spans and also gcUsesSpanDartboard.
+	// pageUseSpanInlineMarkBits is a bitmap where each bit corresponds
+	// to a span, as only spans one page in size can have inline mark bits.
+	// The bit indicates that the span has a spanInlineMarkBits struct
+	// stored directly at the top end of the span's memory.
 	pageUseSpanInlineMarkBits [pagesPerArena / 8]uint8
 
 	// checkmarks stores the debug.gccheckmark state. It is only

src/testing/synctest/helper_test.go

@@ -0,0 +1,15 @@
+// Copyright 2025 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package synctest_test
+
+import "testing"
+
+// helperLog is a t.Helper which logs.
+// Since it is a helper, the log prefix should contain
+// the caller's file, not helper_test.go.
+func helperLog(t *testing.T, s string) {
+	t.Helper()
+	t.Log(s)
+}

src/testing/synctest/synctest_test.go

@@ -140,6 +140,18 @@ func TestRun(t *testing.T) {
 	})
 }
 
+func TestHelper(t *testing.T) {
+	runTest(t, []string{"-test.v"}, func() {
+		synctest.Test(t, func(t *testing.T) {
+			helperLog(t, "log in helper")
+		})
+	}, `^=== RUN   TestHelper
+    synctest_test.go:.* log in helper
+--- PASS: TestHelper.*
+PASS
+$`)
+}
+
 func wantPanic(t *testing.T, want string) {
 	if e := recover(); e != nil {
 		if got := fmt.Sprint(e); got != want {

src/testing/testing.go

@@ -1261,6 +1261,9 @@ func (c *common) Skipped() bool {
 // When printing file and line information, that function will be skipped.
 // Helper may be called simultaneously from multiple goroutines.
 func (c *common) Helper() {
+	if c.isSynctest {
+		c = c.parent
+	}
 	c.mu.Lock()
 	defer c.mu.Unlock()
 	if c.helperPCs == nil {