[dev.typeparams] all: merge dev.regabi (07569da) into dev.typeparams

Conflicts:

- test/fixedbugs/issue27595.go
- test/fixedbugs/issue30087.go
- test/used.go

Merge List:

+ 2020-12-28 07569dac4e [dev.regabi] all: merge master (1d78139) into dev.regabi
+ 2020-12-28 76136be027 [dev.regabi] cmd/compile: check for recursive import in ImportBody
+ 2020-12-28 fda7ec3a3f [dev.regabi] cmd/compile: remove Name.IsDDD, etc
+ 2020-12-28 098a6490b9 [dev.regabi] cmd/compile: remove Declare in makepartialcall
+ 2020-12-28 137f0d2e06 [dev.regabi] cmd/compile: remove unnecessary Name.Sym call
+ 2020-12-28 3383b5c74a [dev.regabi] cmd/compile: flatten dependency graph [generated]
+ 2020-12-28 f8afb8216a [dev.regabi] cmd/compile: rename CommStmt and CaseStmt [generated]
+ 2020-12-28 5f3bd59a0d [dev.regabi] cmd/compile: remove some unneeded code in package ir
+ 2020-12-28 3bdafb0d82 [dev.regabi] cmd/compile: remove CommStmt.List
+ 2020-12-28 2ecf52b841 [dev.regabi] cmd/compile: separate CommStmt from CaseStmt
+ 2020-12-28 ed9772e130 [dev.regabi] cmd/compile: add explicit file name in types generation
+ 2020-12-28 a59d26603f [dev.regabi] cmd/compile: use []*CaseStmt in {Select,Switch}Stmt
+ 2020-12-28 fbc4458c06 [dev.regabi] cmd/compile: simplify some tree traversal code
+ 2020-12-28 6c67677541 [dev.regabi] cmd/compile: simplify FuncName and PkgFuncName
+ 2020-12-28 676d794b81 [dev.regabi] cmd/compile: remove refersToCommonName
+ 2020-12-28 c98548e110 [dev.regabi] cmd/compile: merge ascompatee, ascompatee1, and reorder3
+ 2020-12-28 4c215c4fa9 [dev.regabi] cmd/compile: simplify and optimize reorder3
+ 2020-12-28 e6c973198d [dev.regabi] cmd/compile: stop mangling SelectorExpr.Sel for ODOTMETH
+ 2020-12-28 135ce1c485 [dev.regabi] cmd/compile: desugar OMETHEXPR into ONAME during walk
+ 2020-12-28 0f732f8c91 [dev.regabi] cmd/compile: minor walkExpr cleanups
+ 2020-12-28 0de8eafd98 [dev.regabi] cmd/compile: remove SelectorExpr.Offset field
+ 2020-12-28 a4f335f420 [dev.regabi] cmd/compile: always use a Field for ODOTPTR expressions
+ 2020-12-26 1d78139128 runtime/cgo: fix Android build with NDK 22
+ 2020-12-25 2018b68a65 net/mail: don't use MDT in test
+ 2020-12-25 e4f293d853 [dev.regabi] cmd/compile: fix OCALLMETH desugaring
+ 2020-12-25 1d9a1f67d5 [dev.regabi] cmd/compile: don't emit reflect data for method types
+ 2020-12-25 396b6c2e7c [dev.regabi] cmd/compile: cleanup assignment typechecking
+ 2020-12-25 e24d2f3d05 [dev.regabi] cmd/compile: remove typ from RangeStmt
+ 2020-12-25 2785c691c2 [dev.regabi] cmd/compile: cleanup devirtualization docs
+ 2020-12-25 4b1d0fe66f [dev.regabi] cmd/compile: new devirtualization pkg [generated]
+ 2020-12-24 082cc8b7d9 [dev.regabi] cmd/compile: change ir.IsAssignable -> ir.IsAddressable
+ 2020-12-24 27b248b307 [dev.regabi] cmd/compile: separate range stmt Vars to Key, Value nodes
+ 2020-12-23 40818038bf [dev.regabi] cmd/compile: change CaseStmt.Vars to Var
+ 2020-12-23 b116404444 runtime: shift timeHistogram buckets and allow negative durations
+ 2020-12-23 8db7e2fecd runtime: fix allocs-by-size and frees-by-size buckets
+ 2020-12-23 fb96f07e1a runtime: fix nStackRoots comment about stack roots
+ 2020-12-23 d1502b3c72 lib/time, time/tzdata: update tzdata to 2020e
+ 2020-12-23 30c99cbb7a cmd/go: add the Retract field to 'go help mod edit' definition of the GoMod struct
+ 2020-12-23 49d0b239cb doc: fix a typo in contribute.html
+ 2020-12-23 9eeed291bc [dev.regabi] cmd/compile: eliminate usage of ir.Node in liveness
+ 2020-12-23 d1d64e4cea [dev.regabi] cmd/compile: split SliceExpr.List into separate fields
+ 2020-12-23 98a73030b0 cmd/go: in 'go get', promote named implicit dependencies to explicit
+ 2020-12-23 d19018e8f1 [dev.regabi] cmd/compile: split SliceHeaderExpr.LenCap into separate fields
+ 2020-12-23 53f082b0ee [dev.regabi] cmd/compile: cleanup export code further
+ 2020-12-23 31267f82e1 [dev.regabi] cmd/compile: simplify function/interface/struct typechecking
+ 2020-12-23 addade2cce [dev.regabi] cmd/compile: prefer types constructors over typecheck
+ 2020-12-23 18ebfb49e9 [dev.regabi] cmd/compile: cleanup noder
+ 2020-12-23 87a592b356 [dev.regabi] cmd/compile: cleanup import/export code
+ 2020-12-23 5898025026 [dev.regabi] cmd/compile: update mkbuiltin.go to use new type constructors
+ 2020-12-23 63c96c2ee7 [dev.regabi] cmd/compile: update mkbuiltin.go and re-enable TestBuiltin
+ 2020-12-23 fd6ba1c8a2 os/signal: fix a deadlock with syscall.AllThreadsSyscall() use
+ 2020-12-23 b0b0d98283 runtime: linux iscgo support for not blocking nptl signals
+ 2020-12-22 223331fc0c cmd/go/internal/modload: add hint for missing implicit dependency

Change-Id: Iecb8a7dfb401b6ab383e97101cd81bfc201683f6

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

@@ -510,11 +510,7 @@ func (p *noder) importDecl(imp *syntax.ImportDecl) {
 func (p *noder) varDecl(decl *syntax.VarDecl) []ir.Node {
 	names := p.declNames(ir.ONAME, decl.NameList)
 	typ := p.typeExprOrNil(decl.Type)
-
-	var exprs []ir.Node
-	if decl.Values != nil {
-		exprs = p.exprList(decl.Values)
-	}
+	exprs := p.exprList(decl.Values)
 
 	if pragma, ok := decl.Pragma.(*pragmas); ok {
 		if len(pragma.Embeds) > 0 {
@@ -753,10 +749,14 @@ func (p *noder) param(param *syntax.Field, dddOk, final bool) *ir.Field {
 }
 
 func (p *noder) exprList(expr syntax.Expr) []ir.Node {
-	if list, ok := expr.(*syntax.ListExpr); ok {
-		return p.exprs(list.ElemList)
+	switch expr := expr.(type) {
+	case nil:
+		return nil
+	case *syntax.ListExpr:
+		return p.exprs(expr.ElemList)
+	default:
+		return []ir.Node{p.expr(expr)}
 	}
-	return []ir.Node{p.expr(expr)}
 }
 
 func (p *noder) exprs(exprs []syntax.Expr) []ir.Node {
@@ -775,17 +775,14 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 	case *syntax.Name:
 		return p.mkname(expr)
 	case *syntax.BasicLit:
-		n := ir.NewLiteral(p.basicLit(expr))
+		n := ir.NewBasicLit(p.pos(expr), p.basicLit(expr))
 		if expr.Kind == syntax.RuneLit {
 			n.SetType(types.UntypedRune)
 		}
 		n.SetDiag(expr.Bad) // avoid follow-on errors if there was a syntax error
 		return n
 	case *syntax.CompositeLit:
-		n := ir.NewCompLitExpr(p.pos(expr), ir.OCOMPLIT, nil, nil)
-		if expr.Type != nil {
-			n.Ntype = ir.Node(p.expr(expr.Type)).(ir.Ntype)
-		}
+		n := ir.NewCompLitExpr(p.pos(expr), ir.OCOMPLIT, p.typeExpr(expr.Type), nil)
 		l := p.exprs(expr.ElemList)
 		for i, e := range l {
 			l[i] = p.wrapname(expr.ElemList[i], e)
@@ -818,17 +815,16 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 		if expr.Full {
 			op = ir.OSLICE3
 		}
-		n := ir.NewSliceExpr(p.pos(expr), op, p.expr(expr.X))
+		x := p.expr(expr.X)
 		var index [3]ir.Node
-		for i, x := range &expr.Index {
-			if x != nil {
-				index[i] = p.expr(x)
+		for i, n := range &expr.Index {
+			if n != nil {
+				index[i] = p.expr(n)
 			}
 		}
-		n.SetSliceBounds(index[0], index[1], index[2])
-		return n
+		return ir.NewSliceExpr(p.pos(expr), op, x, index[0], index[1], index[2])
 	case *syntax.AssertExpr:
-		return ir.NewTypeAssertExpr(p.pos(expr), p.expr(expr.X), p.typeExpr(expr.Type).(ir.Ntype))
+		return ir.NewTypeAssertExpr(p.pos(expr), p.expr(expr.X), p.typeExpr(expr.Type))
 	case *syntax.Operation:
 		if expr.Op == syntax.Add && expr.Y != nil {
 			return p.sum(expr)
@@ -852,8 +848,7 @@ func (p *noder) expr(expr syntax.Expr) ir.Node {
 		}
 		return ir.NewBinaryExpr(pos, op, x, y)
 	case *syntax.CallExpr:
-		n := ir.NewCallExpr(p.pos(expr), ir.OCALL, p.expr(expr.Fun), nil)
-		n.Args.Set(p.exprs(expr.ArgList))
+		n := ir.NewCallExpr(p.pos(expr), ir.OCALL, p.expr(expr.Fun), p.exprs(expr.ArgList))
 		n.IsDDD = expr.HasDots
 		return n
 
@@ -1120,7 +1115,7 @@ func (p *noder) stmt(stmt syntax.Stmt) ir.Node {
 func (p *noder) stmtFall(stmt syntax.Stmt, fallOK bool) ir.Node {
 	p.setlineno(stmt)
 	switch stmt := stmt.(type) {
-	case *syntax.EmptyStmt:
+	case nil, *syntax.EmptyStmt:
 		return nil
 	case *syntax.LabeledStmt:
 		return p.labeledStmt(stmt, fallOK)
@@ -1193,12 +1188,7 @@ func (p *noder) stmtFall(stmt syntax.Stmt, fallOK bool) ir.Node {
 		}
 		return ir.NewGoDeferStmt(p.pos(stmt), op, p.expr(stmt.Call))
 	case *syntax.ReturnStmt:
-		var results []ir.Node
-		if stmt.Results != nil {
-			results = p.exprList(stmt.Results)
-		}
-		n := ir.NewReturnStmt(p.pos(stmt), nil)
-		n.Results.Set(results)
+		n := ir.NewReturnStmt(p.pos(stmt), p.exprList(stmt.Results))
 		if len(n.Results) == 0 && ir.CurFunc != nil {
 			for _, ln := range ir.CurFunc.Dcl {
 				if ln.Class_ == ir.PPARAM {
@@ -1292,14 +1282,11 @@ func (p *noder) blockStmt(stmt *syntax.BlockStmt) []ir.Node {
 
 func (p *noder) ifStmt(stmt *syntax.IfStmt) ir.Node {
 	p.openScope(stmt.Pos())
-	n := ir.NewIfStmt(p.pos(stmt), nil, nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
+	init := p.stmt(stmt.Init)
+	n := ir.NewIfStmt(p.pos(stmt), p.expr(stmt.Cond), p.blockStmt(stmt.Then), nil)
+	if init != nil {
+		*n.PtrInit() = []ir.Node{init}
 	}
-	if stmt.Cond != nil {
-		n.Cond = p.expr(stmt.Cond)
-	}
-	n.Body.Set(p.blockStmt(stmt.Then))
 	if stmt.Else != nil {
 		e := p.stmt(stmt.Else)
 		if e.Op() == ir.OBLOCK {
@@ -1320,53 +1307,46 @@ func (p *noder) forStmt(stmt *syntax.ForStmt) ir.Node {
 			panic("unexpected RangeClause")
 		}
 
-		n := ir.NewRangeStmt(p.pos(r), nil, p.expr(r.X), nil)
+		n := ir.NewRangeStmt(p.pos(r), nil, nil, p.expr(r.X), nil)
 		if r.Lhs != nil {
 			n.Def = r.Def
-			n.Vars.Set(p.assignList(r.Lhs, n, n.Def))
+			lhs := p.assignList(r.Lhs, n, n.Def)
+			n.Key = lhs[0]
+			if len(lhs) > 1 {
+				n.Value = lhs[1]
+			}
 		}
 		n.Body.Set(p.blockStmt(stmt.Body))
 		p.closeAnotherScope()
 		return n
 	}
 
-	n := ir.NewForStmt(p.pos(stmt), nil, nil, nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
-	}
-	if stmt.Cond != nil {
-		n.Cond = p.expr(stmt.Cond)
-	}
-	if stmt.Post != nil {
-		n.Post = p.stmt(stmt.Post)
-	}
-	n.Body.Set(p.blockStmt(stmt.Body))
+	n := ir.NewForStmt(p.pos(stmt), p.stmt(stmt.Init), p.expr(stmt.Cond), p.stmt(stmt.Post), p.blockStmt(stmt.Body))
 	p.closeAnotherScope()
 	return n
 }
 
 func (p *noder) switchStmt(stmt *syntax.SwitchStmt) ir.Node {
 	p.openScope(stmt.Pos())
-	n := ir.NewSwitchStmt(p.pos(stmt), nil, nil)
-	if stmt.Init != nil {
-		*n.PtrInit() = []ir.Node{p.stmt(stmt.Init)}
-	}
-	if stmt.Tag != nil {
-		n.Tag = p.expr(stmt.Tag)
+
+	init := p.stmt(stmt.Init)
+	n := ir.NewSwitchStmt(p.pos(stmt), p.expr(stmt.Tag), nil)
+	if init != nil {
+		*n.PtrInit() = []ir.Node{init}
 	}
 
 	var tswitch *ir.TypeSwitchGuard
 	if l := n.Tag; l != nil && l.Op() == ir.OTYPESW {
 		tswitch = l.(*ir.TypeSwitchGuard)
 	}
-	n.Cases.Set(p.caseClauses(stmt.Body, tswitch, stmt.Rbrace))
+	n.Cases = p.caseClauses(stmt.Body, tswitch, stmt.Rbrace)
 
 	p.closeScope(stmt.Rbrace)
 	return n
 }
 
-func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []ir.Node {
-	nodes := make([]ir.Node, 0, len(clauses))
+func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitchGuard, rbrace syntax.Pos) []*ir.CaseClause {
+	nodes := make([]*ir.CaseClause, 0, len(clauses))
 	for i, clause := range clauses {
 		p.setlineno(clause)
 		if i > 0 {
@@ -1374,14 +1354,11 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitch
 		}
 		p.openScope(clause.Pos())
 
-		n := ir.NewCaseStmt(p.pos(clause), nil, nil)
-		if clause.Cases != nil {
-			n.List.Set(p.exprList(clause.Cases))
-		}
+		n := ir.NewCaseStmt(p.pos(clause), p.exprList(clause.Cases), nil)
 		if tswitch != nil && tswitch.Tag != nil {
 			nn := typecheck.NewName(tswitch.Tag.Sym())
 			typecheck.Declare(nn, typecheck.DeclContext)
-			n.Vars = []ir.Node{nn}
+			n.Var = nn
 			// keep track of the instances for reporting unused
 			nn.Defn = tswitch
 		}
@@ -1416,13 +1393,11 @@ func (p *noder) caseClauses(clauses []*syntax.CaseClause, tswitch *ir.TypeSwitch
 }
 
 func (p *noder) selectStmt(stmt *syntax.SelectStmt) ir.Node {
-	n := ir.NewSelectStmt(p.pos(stmt), nil)
-	n.Cases.Set(p.commClauses(stmt.Body, stmt.Rbrace))
-	return n
+	return ir.NewSelectStmt(p.pos(stmt), p.commClauses(stmt.Body, stmt.Rbrace))
 }
 
-func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []ir.Node {
-	nodes := make([]ir.Node, 0, len(clauses))
+func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []*ir.CommClause {
+	nodes := make([]*ir.CommClause, len(clauses))
 	for i, clause := range clauses {
 		p.setlineno(clause)
 		if i > 0 {
@@ -1430,12 +1405,7 @@ func (p *noder) commClauses(clauses []*syntax.CommClause, rbrace syntax.Pos) []i
 		}
 		p.openScope(clause.Pos())
 
-		n := ir.NewCaseStmt(p.pos(clause), nil, nil)
-		if clause.Comm != nil {
-			n.List = []ir.Node{p.stmt(clause.Comm)}
-		}
-		n.Body.Set(p.stmts(clause.Body))
-		nodes = append(nodes, n)
+		nodes[i] = ir.NewCommStmt(p.pos(clause), p.stmt(clause.Comm), p.stmts(clause.Body))
 	}
 	if len(clauses) > 0 {
 		p.closeScope(rbrace)
@@ -2001,7 +1971,6 @@ func oldname(s *types.Sym) ir.Node {
 			c = typecheck.NewName(s)
 			c.Class_ = ir.PAUTOHEAP
 			c.SetIsClosureVar(true)
-			c.SetIsDDD(n.IsDDD())
 			c.Defn = n
 
 			// Link into list of active closure variables.