[dev.typeparams] all: merge master (fdab5be) into dev.typeparams

Two non-conflict changes included because they're needed for all.bash:

1. Bump internal/goversion.Version to 18. This will happen eventually
anyway (dev.typeparams will not be merged back to Go 1.17), and is
needed for cmd/api to allow new API additions.

2. Add fixedbugs/issue46725.go (new test added on master) to the list
of known failures for -G=3. This test exercises a bug that was fixed
in typecheck, but -G=3 mode has duplicated that code and will need to
be fixed as well. That's outside of the scope of a merge.

Conflicts:

- src/runtime/traceback.go

  Nearby lines were removed on both master and dev.typeparams.

Merge List:

+ 2021-06-14 fdab5be159 doc/go1.17: further revise OpenBSD release notes
+ 2021-06-14 326ea438bb cmd/compile: rewrite a, b = f() to use temporaries when type not identical
+ 2021-06-14 3249b645c9 cmd/compile: factor out rewrite multi-valued f()
+ 2021-06-13 14305bf0b9 misc/cgo: generate Windows import libraries for clang
+ 2021-06-13 24cff0f044 cmd/go, misc/cgo: skip test if no .edata
+ 2021-06-13 67b1b6a2e3 cmd/compile: allow ir.OSLICE2ARRPTR in mayCall
+ 2021-06-12 1ed0d129e9 runtime: testprogcgo: don't call exported Go functions directly from Go
+ 2021-06-12 9d46ee5ac4 reflect: handle stack-to-register translation in callMethod
+ 2021-06-11 e552a6d312 cmd/go: remove hint when no module is suggested
+ 2021-06-11 16b5d766d8 syscall: do not load native libraries on non-native powershell on arm
+ 2021-06-11 77aa209b38 runtime: loop on EINTR in macOS sigNoteSleep
+ 2021-06-11 e2dc6dd5c9 doc/go1.17: clean up formatting of gofmt section
+ 2021-06-11 2f1128461d cmd/go: match Windows paths in TestScript/mod_invalid_version
+ 2021-06-11 2721da2608 doc/go1.17: fix formatting near httptest
+ 2021-06-10 770f1de8c5 net/http: remove test-only private key from production binaries
+ 2021-06-10 8d11b1d117 cmd/go: report the imports of CompiledGoFiles in ImportMap
+ 2021-06-10 dc00dc6c6b crypto/tls: let HTTP/1.1 clients connect to servers with NextProtos "h2"
+ 2021-06-09 27f83723e9 api: promote next to go1.17
+ 2021-06-09 182157c81a doc/go1.17: remove lingering TODO
+ 2021-06-09 a5bc060b42 doc/go1.17: document strconv changes for Go 1.17
+ 2021-06-09 1402b27d46 strconv: document parsing of leading +/-
+ 2021-06-09 df35ade067 doc/go1.17: document //go:build lines
+ 2021-06-09 e4e7807d24 net/http: add AllowQuerySemicolons
+ 2021-06-09 ec3026d032 doc/go1.17: remove TODO for ports section
+ 2021-06-09 e6dda19888 net/url: reject query values with semicolons
+ 2021-06-09 139e935d3c math/big: comment division
+ 2021-06-09 aa5540cd82 cmd/compile: make map.zero symbol content-addressable
+ 2021-06-09 07ca28d529 cmd/link: fix bug in -strictdups checking of BSS symbols
+ 2021-06-08 bcecae2af6 doc/go1.17: mention new possibility of type conversion panicking
+ 2021-06-08 63dcab2e91 doc/go1.17: mention new vet checks sigchanyzer and stdmethods.
+ 2021-06-08 6551763a60 doc/go1.17: mention block profile bias fix
+ 2021-06-08 cb80937bf6 Revert "doc/go1.17: mention block profile bias fix"
+ 2021-06-08 d3e3d03666 net: reject leading zeros in IP address parsers
+ 2021-06-08 da4a640141 doc/go1.17: revise OpenBSD release notes
+ 2021-06-08 689f4c7415 doc/go1.17: mention block profile bias fix
+ 2021-06-08 9afe071c60 doc/go1.17: remove TODO for Tools section
+ 2021-06-08 f753d7223e doc/go1.17: resolve TODO for cmd/cover
+ 2021-06-08 9498b0155d cmd/go: in Go 1.17+ modules, add indirect go.mod dependencies separately from direct ones
+ 2021-06-08 949f00cebe doc/go1.17: add release notes for crypto packages
+ 2021-06-08 0fb3e2c184 doc/go1.17: add a release note for the '-compat' flag to 'go mod tidy'
+ 2021-06-08 2169deb352 cmd/compile: use t.AllMethods when sorting typesByString
+ 2021-06-08 c20bcb6488 runtime: remove out-of-date comments about frame skipping
+ 2021-06-07 39c39ae52f doc: document Go 1.17 language changes
+ 2021-06-07 dc8b558951 cmd/dist: pass -Wno-lto-type-mismatch in swig_callback_lto
+ 2021-06-07 909dd5e010 strconv: ParseFloat: always return ErrSyntax for bad syntax

Change-Id: Iffdf379d0275bbd12d50149ce38634773ced481d

1 files changed, 29 insertions, 12 deletions

diff --git a/src/cmd/compile/internal/typecheck/typecheck.go b/src/cmd/compile/internal/typecheck/typecheck.go
index a6b21f948a..8454b8d5b3 100644
--- a/src/cmd/compile/internal/typecheck/typecheck.go
+++ b/src/cmd/compile/internal/typecheck/typecheck.go
@@ -941,16 +941,18 @@ func typecheckargs(n ir.InitNode) {
 		return
 	}
 
-	// Rewrite f(g()) into t1, t2, ... = g(); f(t1, t2, ...).
-
 	// Save n as n.Orig for fmt.go.
 	if ir.Orig(n) == n {
 		n.(ir.OrigNode).SetOrig(ir.SepCopy(n))
 	}
 
-	as := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, nil)
-	as.Rhs.Append(list...)
+	// Rewrite f(g()) into t1, t2, ... = g(); f(t1, t2, ...).
+	rewriteMultiValueCall(n, list[0])
+}
 
+// rewriteMultiValueCall rewrites multi-valued f() to use temporaries,
+// so the backend wouldn't need to worry about tuple-valued expressions.
+func rewriteMultiValueCall(n ir.InitNode, call ir.Node) {
 	// If we're outside of function context, then this call will
 	// be executed during the generated init function. However,
 	// init.go hasn't yet created it. Instead, associate the
@@ -960,25 +962,40 @@ func typecheckargs(n ir.InitNode) {
 	if static {
 		ir.CurFunc = InitTodoFunc
 	}
-	list = nil
-	for _, f := range t.FieldSlice() {
-		t := Temp(f.Type)
-		as.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, t))
-		as.Lhs.Append(t)
-		list = append(list, t)
+
+	as := ir.NewAssignListStmt(base.Pos, ir.OAS2, nil, []ir.Node{call})
+	results := call.Type().FieldSlice()
+	list := make([]ir.Node, len(results))
+	for i, result := range results {
+		tmp := Temp(result.Type)
+		as.PtrInit().Append(ir.NewDecl(base.Pos, ir.ODCL, tmp))
+		as.Lhs.Append(tmp)
+		list[i] = tmp
 	}
 	if static {
 		ir.CurFunc = nil
 	}
 
+	n.PtrInit().Append(Stmt(as))
+
 	switch n := n.(type) {
+	default:
+		base.Fatalf("rewriteMultiValueCall %+v", n.Op())
 	case *ir.CallExpr:
 		n.Args = list
 	case *ir.ReturnStmt:
 		n.Results = list
+	case *ir.AssignListStmt:
+		if n.Op() != ir.OAS2FUNC {
+			base.Fatalf("rewriteMultiValueCall: invalid op %v", n.Op())
+		}
+		as.SetOp(ir.OAS2FUNC)
+		n.SetOp(ir.OAS2)
+		n.Rhs = make([]ir.Node, len(list))
+		for i, tmp := range list {
+			n.Rhs[i] = AssignConv(tmp, n.Lhs[i].Type(), "assignment")
+		}
 	}
-
-	n.PtrInit().Append(Stmt(as))
 }
 
 func checksliceindex(l ir.Node, r ir.Node, tp *types.Type) bool {