[dev.typeparams] all: merge master (4711bf3) into dev.typeparams

Conflicts:

- src/cmd/compile/internal/walk/builtin.go

  On dev.typeparams, CL 330194 changed OCHECKNIL to not require manual
  SetTypecheck(1) anymore; while on master, CL 331070 got rid of the
  OCHECKNIL altogether by moving the check into the runtime support
  functions.

- src/internal/buildcfg/exp.go

  On master, CL 331109 refactored the logic for parsing the
  GOEXPERIMENT string, so that it could be more easily reused by
  cmd/go; while on dev.typeparams, several CLs tweaked the regabi
  experiment defaults.

Merge List:

+ 2021-06-30 4711bf30e5 doc/go1.17: linkify "language changes" in the runtime section
+ 2021-06-30 ed56ea73e8 path/filepath: deflake TestEvalSymlinksAboveRoot on darwin
+ 2021-06-30 c080d0323b cmd/dist: pass -Wno-unknown-warning-option in swig_callback_lto
+ 2021-06-30 7d0e9e6e74 image/gif: fix typo in the comment (io.ReadByte -> io.ByteReader)
+ 2021-06-30 0fa3265fe1 os: change example to avoid deprecated function
+ 2021-06-30 d19a53338f image: add Uniform.RGBA64At and Rectangle.RGBA64At
+ 2021-06-30 c45e800e0c crypto/x509: don't fail on optional auth key id fields
+ 2021-06-29 f9d50953b9 net: fix failure of TestCVE202133195
+ 2021-06-29 e294b8a49e doc/go1.17: fix typo "MacOS" -> "macOS"
+ 2021-06-29 3463852b76 math/big: fix typo of comment (`BytesScanner` to `ByteScanner`)
+ 2021-06-29 fd4b587da3 cmd/compile: suppress details error for invalid variadic argument type
+ 2021-06-29 e2e05af6e1 cmd/internal/obj/arm64: fix an encoding error of CMPW instruction
+ 2021-06-28 4bb0847b08 cmd/compile,runtime: change unsafe.Slice((*T)(nil), 0) to return []T(nil)
+ 2021-06-28 1519271a93 spec: change unsafe.Slice((*T)(nil), 0) to return []T(nil)
+ 2021-06-28 5385e2386b runtime/internal/atomic: drop Cas64 pointer indirection in comments
+ 2021-06-28 956c81bfe6 cmd/go: add GOEXPERIMENT to `go env` output
+ 2021-06-28 a1d27269d6 cmd/go: prep for 'go env' refactoring
+ 2021-06-28 901510ed4e cmd/link/internal/ld: skip the windows ASLR test when CGO_ENABLED=0
+ 2021-06-28 361159c055 cmd/cgo: fix 'see gmp.go' to 'see doc.go'
+ 2021-06-27 c95464f0ea internal/buildcfg: refactor GOEXPERIMENT parsing code somewhat
+ 2021-06-25 ed01ceaf48 runtime/race: use race build tag on syso_test.go
+ 2021-06-25 d1916e5e84 go/types: in TestCheck/issues.src, import regexp/syntax instead of cmd/compile/internal/syntax
+ 2021-06-25 5160896c69 go/types: in TestStdlib, import from source instead of export data
+ 2021-06-25 d01bc571f7 runtime: make ncgocall a global counter

Change-Id: I1ce4a3b3ff7c824c67ad66dd27d9d5f1d25c0023

diff --cc src/cmd/compile/internal/typecheck/func.go
Simple merge

diff --cc src/cmd/compile/internal/typecheck/typecheck.go
Simple merge

diff --cc src/cmd/compile/internal/walk/builtin.go
Simple merge

diff --cc src/go/types/testdata/check/issues.src
Simple merge

diff --cc src/internal/buildcfg/exp.go
index e87b6221f1eae2f47f683df8191537aa19aabc8f,9a60253aab9b1830815bf4b69ffd3fee32474974..6e8bf30743dfba6a9ab8d5ad669f9e446e6e7948
--- 1/src/internal/buildcfg/exp.go
--- 2/src/internal/buildcfg/exp.go
+++ b/src/internal/buildcfg/exp.go
@@@ -41,9 -40,24 +40,22 @@@ const DefaultGOEXPERIMENT = defaultGOEX
  // Note: must agree with runtime.framepointer_enabled.
  var FramePointerEnabled = GOARCH == "amd64" || GOARCH == "arm64"
  
- func parseExperiments(goarch string) goexperiment.Flags {
+ // ParseGOEXPERIMENT parses a (GOOS, GOARCH, GOEXPERIMENT)
+ // configuration tuple and returns the enabled and baseline experiment
+ // flag sets.
+ //
+ // TODO(mdempsky): Move to internal/goexperiment.
+ func ParseGOEXPERIMENT(goos, goarch, goexp string) (flags, baseline goexperiment.Flags, err error) {
 -      regabiSupported := goarch == "amd64" && (goos == "android" || goos == "linux" || goos == "darwin" || goos == "windows")
++      regabiSupported := goarch == "amd64" || goarch == "arm64"
+ 
+       baseline = goexperiment.Flags{
+               RegabiWrappers: regabiSupported,
 -              RegabiG:        regabiSupported,
+               RegabiReflect:  regabiSupported,
 -              RegabiDefer:    regabiSupported,
+               RegabiArgs:     regabiSupported,
+       }
+ 
        // Start with the statically enabled set of experiments.
-       flags := experimentBaseline
+       flags = baseline
  
        // Pick up any changes to the baseline configuration from the
        // GOEXPERIMENT environment. This can be set at make.bash time
@@@ -106,10 -117,14 +116,10 @@@
                flags.RegabiArgs = false
        }
        // Check regabi dependencies.
 -      if flags.RegabiG && !flags.RegabiWrappers {
 -              err = fmt.Errorf("GOEXPERIMENT regabig requires regabiwrappers")
 -      }
 -      if flags.RegabiArgs && !(flags.RegabiWrappers && flags.RegabiG && flags.RegabiReflect && flags.RegabiDefer) {
 -              err = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabig,regabireflect,regabidefer")
 +      if flags.RegabiArgs && !(flags.RegabiWrappers && flags.RegabiReflect) {
-               Error = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect")
++              err = fmt.Errorf("GOEXPERIMENT regabiargs requires regabiwrappers,regabireflect")
        }
-       return flags
+       return
  }
  
  // expList returns the list of lower-cased experiment names for

diff --cc src/runtime/cgocall.go
Simple merge

diff --cc src/runtime/proc.go
Simple merge

diff --cc src/runtime/slice.go
Simple merge