[pull] master from golang:master

api/next/76821.txt

@@ -0,0 +1,9 @@
+pkg math/big, method (*Int) Divide(*Int, *Int, *Int, RoundingMode) (*Int, *Int) #76821
+pkg math/big, const Trunc = 2 #76821
+pkg math/big, const Trunc RoundingMode #76821
+pkg math/big, const Floor = 4 #76821
+pkg math/big, const Floor RoundingMode #76821
+pkg math/big, const Round = 0 #76821
+pkg math/big, const Round RoundingMode #76821
+pkg math/big, const Ceil = 5 #76821
+pkg math/big, const Ceil RoundingMode #76821

api/next/79042.txt

@@ -0,0 +1 @@
+pkg go/constant, func StringLen(Value) int64 #79042

doc/next/6-stdlib/99-minor/go/constant/79042.md

@@ -0,0 +1 @@
+The new [StringLen] function returns the length of a string [Value]. For an [Unknown] value, the length is 0.

doc/next/6-stdlib/99-minor/math/big/76821.md

@@ -0,0 +1,3 @@
+<!-- go.dev/issue/76821 -->
+[Int] now has method [Int.Divide] to compute quotient and remainder of two [Int] values.
+It supports rounding modes [Trunc], [Floor], [Round] and [Ceil].

src/cmd/compile/internal/importer/genmeth_test.go

@@ -2,6 +2,8 @@
 // Use of this source code is governed by a BSD-style
 // license that can be found in the LICENSE file.
 
+//go:build goexperiment.genericmethods
+
 package importer
 
 import (

src/cmd/compile/internal/noder/unified.go

@@ -26,12 +26,12 @@ import (
 )
 
 // uirVersion is the unified IR version to use for encoding/decoding.
-// Use V4 for generic methods. Revert to V3 if the GOEXPERIMENT is enabled.
+// Use V4 for generic methods if the GOEXPERIMENT is enabled.
 var uirVersion = func() pkgbits.Version {
 	if buildcfg.Experiment.GenericMethods {
-		return pkgbits.V3
+		return pkgbits.V4
 	}
-	return pkgbits.V4
+	return pkgbits.V3
 }()
 
 // localPkgReader holds the package reader used for reading the local

src/cmd/compile/internal/types2/builtins.go

@@ -153,7 +153,7 @@ func (check *Checker) builtin(x *operand, call *syntax.CallExpr, id builtinId) (
 			if isString(t) && id == _Len {
 				if x.mode() == constant_ {
 					mode = constant_
-					val = constant.MakeInt64(int64(len(constant.StringVal(x.val))))
+					val = constant.MakeInt64(constant.StringLen(x.val))
 				} else {
 					mode = value
 				}

src/cmd/compile/internal/types2/const.go

@@ -49,16 +49,15 @@ func (check *Checker) overflow(x *operand, opPos syntax.Pos) {
 		return
 	}
 
-	const maxLen = int(2e9) // cmd/internal/obj.MaxSymSize
-	// Disable the length check for now, as calling constant.StringVal
-	// eagerly constructs the string and can lead to significant memory
-	// usage increase. We may want a StringLen function.
-	// TODO(go.dev/issue/78346): reenable the check.
-	if false && x.val.Kind() == constant.String && len(constant.StringVal(x.val)) > maxLen {
-		check.errorf(atPos(opPos), InvalidConstVal, "constant string too long (%d bytes > %d bytes)",
-			len(constant.StringVal(x.val)), maxLen)
-		x.val = constant.MakeUnknown()
-		return
+	// String values must not become arbitrarily long (go.dev/issue/78346).
+	const maxLen = int64(2e9) // cmd/internal/obj.MaxSymSize
+	if x.val.Kind() == constant.String {
+		len := constant.StringLen(x.val)
+		if len > maxLen {
+			check.errorf(atPos(opPos), InvalidConstVal, "constant string too long (%d bytes > %d bytes)", len, maxLen)
+			x.val = constant.MakeUnknown()
+			return
+		}
 	}
 }
 

src/cmd/compile/internal/types2/index.go

@@ -77,7 +77,7 @@ func (check *Checker) indexExpr(x *operand, e *syntax.IndexExpr) (isFuncInst boo
 		if isString(typ) {
 			valid = true
 			if x.mode() == constant_ {
-				length = int64(len(constant.StringVal(x.val)))
+				length = constant.StringLen(x.val)
 			}
 			// an indexed string always yields a byte value
 			// (not a constant) even if the string and the
@@ -302,7 +302,7 @@ func (check *Checker) sliceExpr(x *operand, e *syntax.SliceExpr) {
 			}
 			valid = true
 			if x.mode() == constant_ {
-				length = int64(len(constant.StringVal(x.val)))
+				length = constant.StringLen(x.val)
 			}
 			// spec: "For untyped string operands the result
 			// is a non-constant value of type string."

src/cmd/go.mod

@@ -6,7 +6,7 @@ require (
 	github.com/google/pprof v0.0.0-20260115054156-294ebfa9ad83
 	golang.org/x/arch v0.23.1-0.20260109160903-657d90bd6695
 	golang.org/x/build v0.0.0-20260122183339-3ba88df37c64
-	golang.org/x/mod v0.35.0
+	golang.org/x/mod v0.36.1-0.20260513122029-343ee60345a1
 	golang.org/x/sync v0.20.0
 	golang.org/x/sys v0.44.0
 	golang.org/x/telemetry v0.0.0-20260409153401-be6f6cb8b1fa

src/cmd/go.sum

@@ -10,8 +10,8 @@ golang.org/x/arch v0.23.1-0.20260109160903-657d90bd6695 h1:q45HsUyFzBjBk4mHGgUew
 golang.org/x/arch v0.23.1-0.20260109160903-657d90bd6695/go.mod h1:dNHoOeKiyja7GTvF9NJS1l3Z2yntpQNzgrjh1cU103A=
 golang.org/x/build v0.0.0-20260122183339-3ba88df37c64 h1:BNhBATNmH/VtzGolB+ksQPPvn6ZyffiR8TmKenqNo+A=
 golang.org/x/build v0.0.0-20260122183339-3ba88df37c64/go.mod h1:3QmSbNil8ZWqC94m80Glej1v8b92gYzPIQPTtSa0c+4=
-golang.org/x/mod v0.35.0 h1:Ww1D637e6Pg+Zb2KrWfHQUnH2dQRLBQyAtpr/haaJeM=
-golang.org/x/mod v0.35.0/go.mod h1:+GwiRhIInF8wPm+4AoT6L0FA1QWAad3OMdTRx4tFYlU=
+golang.org/x/mod v0.36.1-0.20260513122029-343ee60345a1 h1:C0TwvxhsI0bHc1TbK4QEa5PCMrHiST7y/lpX4MVW3KM=
+golang.org/x/mod v0.36.1-0.20260513122029-343ee60345a1/go.mod h1:moc6ELqsWcOw5Ef3xVprK5ul/MvtVvkIXLziUOICjUQ=
 golang.org/x/sync v0.20.0 h1:e0PTpb7pjO8GAtTs2dQ6jYa5BWYlMuX047Dco/pItO4=
 golang.org/x/sync v0.20.0/go.mod h1:9xrNwdLfx4jkKbNva9FpL6vEN7evnE43NNNJQ2LF3+0=
 golang.org/x/sys v0.44.0 h1:ildZl3J4uzeKP07r2F++Op7E9B29JRUy+a27EibtBTQ=

src/cmd/go/internal/modload/init.go

@@ -1989,8 +1989,10 @@ func UpdateGoModFromReqs(ld *Loader, ctx context.Context, opts WriteOpts) (befor
 	// Update require blocks.
 	if gover.Compare(goVersion, gover.SeparateIndirectVersion) < 0 {
 		modFile.SetRequire(list)
-	} else {
+	} else if gover.Compare(goVersion, gover.SimplifyRequireVersion) < 0 {
 		modFile.SetRequireSeparateIndirect(list)
+	} else {
+		modFile.SetRequireAtMostTwo(list)
 	}
 	modFile.Cleanup()
 	after, err = modFile.Format()

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

@@ -0,0 +1,155 @@
+# If go.mod has go 1.27 or higher, multiple require blocks should be
+# consolidated.  Even those with comments.
+
+cp go.mod.127 go.mod
+go mod tidy
+cmp go.mod go.mod.127tidy
+
+# If go.mod has go 1.26, blocks with comments should be preserved.
+cp go.mod.126 go.mod
+go mod tidy
+cmp go.mod go.mod.126tidy
+
+-- go.mod.127 --
+module example.com/m
+
+go 1.27
+
+require example.com/a v1.0.0
+
+// Block comment
+require (
+	example.com/b v1.0.0
+)
+
+// Another block comment
+require (
+	example.com/d v1.0.0 // an inline comment
+  example.com/c v1.0.0 // indirect
+)
+
+// A third block comment
+require (
+  example.com/e v1.0.0 // indirect
+)
+
+replace (
+	example.com/a v1.0.0 => ./a
+	example.com/b v1.0.0 => ./b
+	example.com/c v1.0.0 => ./c
+	example.com/d v1.0.0 => ./d
+	example.com/e v1.0.0 => ./e
+)
+-- go.mod.127tidy --
+module example.com/m
+
+go 1.27
+
+// Block comment
+//
+// Another block comment
+require (
+	example.com/a v1.0.0
+	example.com/b v1.0.0
+	example.com/d v1.0.0 // an inline comment
+)
+
+// A third block comment
+require (
+	example.com/c v1.0.0 // indirect
+	example.com/e v1.0.0 // indirect
+)
+
+replace (
+	example.com/a v1.0.0 => ./a
+	example.com/b v1.0.0 => ./b
+	example.com/c v1.0.0 => ./c
+	example.com/d v1.0.0 => ./d
+	example.com/e v1.0.0 => ./e
+)
+-- go.mod.126 --
+module example.com/m
+
+go 1.26
+
+require example.com/a v1.0.0
+
+// Block comment
+require (
+	example.com/b v1.0.0
+	example.com/d v1.0.0
+)
+
+require example.com/c v1.0.0 // indirect
+
+replace (
+	example.com/a v1.0.0 => ./a
+	example.com/b v1.0.0 => ./b
+	example.com/c v1.0.0 => ./c
+	example.com/d v1.0.0 => ./d
+	example.com/e v1.0.0 => ./e
+)
+-- go.mod.126tidy --
+module example.com/m
+
+go 1.26
+
+require example.com/a v1.0.0
+
+// Block comment
+require (
+	example.com/b v1.0.0
+	example.com/d v1.0.0
+)
+
+require (
+	example.com/c v1.0.0 // indirect
+	example.com/e v1.0.0 // indirect
+)
+
+replace (
+	example.com/a v1.0.0 => ./a
+	example.com/b v1.0.0 => ./b
+	example.com/c v1.0.0 => ./c
+	example.com/d v1.0.0 => ./d
+	example.com/e v1.0.0 => ./e
+)
+-- m.go --
+package m
+import _ "example.com/a"
+import _ "example.com/b"
+import _ "example.com/d"
+
+-- a/go.mod --
+module example.com/a
+go 1.26
+require example.com/c v1.0.0
+require example.com/e v1.0.0
+-- a/a.go --
+package a
+import _ "example.com/c"
+import _ "example.com/e"
+
+-- b/go.mod --
+module example.com/b
+go 1.26
+-- b/b.go --
+package b
+
+-- c/go.mod --
+module example.com/c
+go 1.26
+-- c/c.go --
+package c
+
+-- d/go.mod --
+module example.com/d
+go 1.26
+-- d/d.go --
+package d
+
+-- e/go.mod --
+module example.com/e
+go 1.26
+-- e/e.go --
+package e