[dev.typeparams] all: merge master (46fd547) into dev.typeparams

Conflicts:

- src/go/types/check_test.go

  CL 324730 on dev.typeparams changed the directory paths in TestCheck,
  TestExamples, and TestFixedbugs and renamed checkFiles to testFiles;
  whereas CL 337529 on master added a new test case just above them and
  that used checkFiles.

Merge List:

+ 2021-08-12 46fd547d89 internal/goversion: update Version to 1.18
+ 2021-08-12 5805efc78e doc/go1.17: remove draft notice
+ 2021-08-12 39634e7dae CONTRIBUTORS: update for the Go 1.17 release
+ 2021-08-12 095bb790e1 os/exec: re-enable LookPathTest/16
+ 2021-08-11 dea23e9ca8 src/make.*: make --no-clean flag a no-op that prints a warning
+ 2021-08-11 d4c0ed26ac doc/go1.17: linker passes -I to extld as -Wl,--dynamic-linker
+ 2021-08-10 1f9c9d8530 doc: use "high address/low address" instead of "top/bottom"
+ 2021-08-09 f1dce319ff cmd/go: with -mod=vendor, don't panic if there are duplicate requirements
+ 2021-08-09 7aeaad5c86 runtime/cgo: when using msan explicitly unpoison cgoCallers
+ 2021-08-08 507cc341ec doc: add example for conversion from slice expressions to array ptr
+ 2021-08-07 891547e2d4 doc/go1.17: fix a typo introduced in CL 335135
+ 2021-08-06 8eaf4d16bc make.bash: do not overwrite GO_LDSO if already set
+ 2021-08-06 63b968f4f8 doc/go1.17: clarify Modules changes
+ 2021-08-06 70546f6404 runtime: allow arm64 SEH to be called if illegal instruction
+ 2021-08-05 fd45e267c2 runtime: warn that KeepAlive is not an unsafe.Pointer workaround
+ 2021-08-04 6e738868a7 net/http: speed up and deflake TestCancelRequestWhenSharingConnection
+ 2021-08-02 8a7ee4c51e io/fs: don't use absolute path in DirEntry.Name doc
+ 2021-07-31 b8ca6e59ed all: gofmt
+ 2021-07-30 b7a85e0003 net/http/httputil: close incoming ReverseProxy request body
+ 2021-07-29 70fd4e47d7 runtime: avoid possible preemption when returning from Go to C
+ 2021-07-28 9eee0ed439 cmd/go: fix go.mod file name printed in error messages for replacements
+ 2021-07-28 b39e0f461c runtime: don't crash on nil pointers in checkptrAlignment
+ 2021-07-27 7cd10c1149 cmd/go: use .mod instead of .zip to determine if version has go.mod file
+ 2021-07-27 c8cf0f74e4 cmd/go: add missing flag in UsageLine
+ 2021-07-27 7ba8e796c9 testing: clarify T.Name returns a distinct name of the running test
+ 2021-07-27 33ff155970 go/types: preserve untyped constants on the RHS of a shift expression
+ 2021-07-26 840e583ff3 runtime: correct variable name in comment
+ 2021-07-26 bfbb288574 runtime: remove adjustTimers counter
+ 2021-07-26 9c81fd53b3 cmd/vet: add missing copyright header

Change-Id: Ia80604d24c6f4205265683024e3100769cf32065

1 files changed, 44 insertions, 40 deletions

diff --git a/src/cmd/go/internal/modload/modfile.go b/src/cmd/go/internal/modload/modfile.go
index d280945ea6..03e02e73b6 100644
--- a/src/cmd/go/internal/modload/modfile.go
+++ b/src/cmd/go/internal/modload/modfile.go
@@ -595,47 +595,14 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 	}
 	c := rawGoModSummaryCache.Do(m, func() interface{} {
 		summary := new(modFileSummary)
-		var f *modfile.File
-		if m.Version == "" {
-			// m is a replacement module with only a file path.
-			dir := m.Path
-			if !filepath.IsAbs(dir) {
-				dir = filepath.Join(ModRoot(), dir)
-			}
-			gomod := filepath.Join(dir, "go.mod")
-			var data []byte
-			var err error
-			if gomodActual, ok := fsys.OverlayPath(gomod); ok {
-				// Don't lock go.mod if it's part of the overlay.
-				// On Plan 9, locking requires chmod, and we don't want to modify any file
-				// in the overlay. See #44700.
-				data, err = os.ReadFile(gomodActual)
-			} else {
-				data, err = lockedfile.Read(gomodActual)
-			}
-			if err != nil {
-				return cached{nil, module.VersionError(m, fmt.Errorf("reading %s: %v", base.ShortPath(gomod), err))}
-			}
-			f, err = modfile.ParseLax(gomod, data, nil)
-			if err != nil {
-				return cached{nil, module.VersionError(m, fmt.Errorf("parsing %s: %v", base.ShortPath(gomod), err))}
-			}
-		} else {
-			if !semver.IsValid(m.Version) {
-				// Disallow the broader queries supported by fetch.Lookup.
-				base.Fatalf("go: internal error: %s@%s: unexpected invalid semantic version", m.Path, m.Version)
-			}
-
-			data, err := modfetch.GoMod(m.Path, m.Version)
-			if err != nil {
-				return cached{nil, err}
-			}
-			f, err = modfile.ParseLax("go.mod", data, nil)
-			if err != nil {
-				return cached{nil, module.VersionError(m, fmt.Errorf("parsing go.mod: %v", err))}
-			}
+		name, data, err := rawGoModData(m)
+		if err != nil {
+			return cached{nil, err}
+		}
+		f, err := modfile.ParseLax(name, data, nil)
+		if err != nil {
+			return cached{nil, module.VersionError(m, fmt.Errorf("parsing %s: %v", base.ShortPath(name), err))}
 		}
-
 		if f.Module != nil {
 			summary.module = f.Module.Mod
 			summary.deprecated = f.Module.Deprecated
@@ -671,6 +638,43 @@ func rawGoModSummary(m module.Version) (*modFileSummary, error) {
 
 var rawGoModSummaryCache par.Cache // module.Version → rawGoModSummary result
 
+// rawGoModData returns the content of the go.mod file for module m, ignoring
+// all replacements that may apply to m.
+//
+// rawGoModData cannot be used on the Target module.
+//
+// Unlike rawGoModSummary, rawGoModData does not cache its results in memory.
+// Use rawGoModSummary instead unless you specifically need these bytes.
+func rawGoModData(m module.Version) (name string, data []byte, err error) {
+	if m.Version == "" {
+		// m is a replacement module with only a file path.
+		dir := m.Path
+		if !filepath.IsAbs(dir) {
+			dir = filepath.Join(ModRoot(), dir)
+		}
+		name = filepath.Join(dir, "go.mod")
+		if gomodActual, ok := fsys.OverlayPath(name); ok {
+			// Don't lock go.mod if it's part of the overlay.
+			// On Plan 9, locking requires chmod, and we don't want to modify any file
+			// in the overlay. See #44700.
+			data, err = os.ReadFile(gomodActual)
+		} else {
+			data, err = lockedfile.Read(gomodActual)
+		}
+		if err != nil {
+			return "", nil, module.VersionError(m, fmt.Errorf("reading %s: %v", base.ShortPath(name), err))
+		}
+	} else {
+		if !semver.IsValid(m.Version) {
+			// Disallow the broader queries supported by fetch.Lookup.
+			base.Fatalf("go: internal error: %s@%s: unexpected invalid semantic version", m.Path, m.Version)
+		}
+		name = "go.mod"
+		data, err = modfetch.GoMod(m.Path, m.Version)
+	}
+	return name, data, err
+}
+
 // queryLatestVersionIgnoringRetractions looks up the latest version of the
 // module with the given path without considering retracted or excluded
 // versions.