Merge e0ce9653db 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/internal/work/exec.go

@@ -1899,12 +1899,21 @@ func (b *Builder) installHeader(ctx context.Context, a *Action) error {
 // regular outputs (instrumented source files) the cover tool also
 // writes a separate file (appearing first in the list of outputs)
 // that will contain coverage counters and meta-data.
+//
+// When an overlay is in use, it ensures the coverage tool processes the overlaid
+// files rather than the original source files.
 func (b *Builder) cover(a *Action, infiles, outfiles []string, varName string, mode string) ([]string, error) {
 	pkgcfg := a.Objdir + "pkgcfg.txt"
 	covoutputs := a.Objdir + "coveroutfiles.txt"
 	odir := filepath.Dir(outfiles[0])
 	cv := filepath.Join(odir, "covervars.go")
 	outfiles = append([]string{cv}, outfiles...)
+	overlayInfiles := make([]string, 0, len(infiles))
+	for _, f := range infiles {
+		overlayPath := fsys.Actual(f)
+		overlayInfiles = append(overlayInfiles, overlayPath)
+	}
+
 	if err := b.writeCoverPkgInputs(a, pkgcfg, covoutputs, outfiles); err != nil {
 		return nil, err
 	}
@@ -1914,7 +1923,7 @@ func (b *Builder) cover(a *Action, infiles, outfiles []string, varName string, m
 		"-var", varName,
 		"-outfilelist", covoutputs,
 	}
-	args = append(args, infiles...)
+	args = append(args, overlayInfiles...)
 	if err := b.Shell(a).run(a.Objdir, "", nil,
 		cfg.BuildToolexec, args); err != nil {
 		return nil, err

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

@@ -0,0 +1,77 @@
+# Test that coverage works correctly with overlays
+
+env GO111MODULE=on
+
+mkdir covmod
+cd covmod
+
+-- go.mod --
+module example.com/covmod
+
+go 1.25
+
+-- a.go --
+package a
+
+func Hello() string { 
+    return "Hello: World"
+}
+
+func Helper() string {
+    return "helper"
+}
+
+-- a_test.go --
+package a
+
+import "testing"
+
+func TestHello(t *testing.T) {
+	got := Hello()
+	expected := "Hello: World"
+	if got != expected {
+		t.Fatalf("Hello() = %q, want %q", got, expected)
+	}
+}
+
+func TestHelper(t *testing.T) {
+	got := Helper()
+	expected := "helper"
+	if got != expected {
+		t.Fatalf("Helper() = %q, want %q", got, expected)
+	}
+}
+
+-- overlay/a.go --
+package a
+
+func Hello() string {
+    panic("overlay")
+}
+
+func Helper() string {
+    panic("overlay helper")
+}
+
+-- overlay.json --
+{"Replace": {"a.go": "overlay/a.go"}}
+
+exists overlay.json
+
+go mod tidy
+
+go test -v
+
+! exec sh -c '! go test -overlay=overlay.json -coverpkg=example.com/covmod 2>&1 | grep -q "panic: overlay"'
+
+! exec sh -c '! go test -overlay=overlay.json -run=TestHello -coverpkg=example.com/covmod 2>&1 | grep -q "panic: overlay"'
+
+! exec sh -c '! go test -overlay=overlay.json -run=TestHelper -coverpkg=example.com/covmod 2>&1 | grep -q "panic: overlay helper"'
+
+! go test -overlay=overlay.json -coverpkg=example.com/covmod -coverprofile=coverage.txt
+
+exists coverage.txt
+
+! grep -q 'overlay/a\.go' coverage.txt
+
+rm -f coverage.txt

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
+	// pageUseSpanInlineMarkBits is a bitmap where each bit corresponds
-	// heap spans and also gcUsesSpanDartboard.
+	// 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 {