Func.End: support AutoLambdaCond/Loop

codebuild.go

@@ -454,6 +454,9 @@ func (p *CodeBuilder) Return(n int, src ...ast.Node) *CodeBuilder {
 		log.Println("Return", n)
 	}
 	fn := p.current.fn
+	if fn.cate != AutoLambdaNormal {
+		p.panicCodeErrorf(getPos(src), getEnd(src), cantUseFlowsInAutoLambda)
+	}
 
 	// For non-inline functions, if stack has fewer elements than expected, it
 	// means compilation of return arguments failed. We still mark return to
@@ -2287,7 +2290,7 @@ func (p *CodeBuilder) Fallthrough() *CodeBuilder {
 	panic("please use fallthrough in case statement")
 }
 
-// For func
+// For loop statement: For (..|None) Then [.. Post] .. End
 func (p *CodeBuilder) For(src ...ast.Node) *CodeBuilder {
 	if debugInstr {
 		log.Println("For")

error_msg_test.go

@@ -134,12 +134,20 @@ func TestErrSwitch(t *testing.T) {
 }
 
 func TestErrAutoLambda(t *testing.T) {
-	codeErrorTest(t, `./foo.gop:5:1: can't use return/continue/break/goto in auto lambda`, func(pkg *gogen.Package) {
+	codeErrorTest(t, `./foo.gop:5:2: can't use return/continue/break/goto in auto lambda`, func(pkg *gogen.Package) {
 		cb := pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg)
 		sig := types.NewSignatureType(nil, nil, nil, nil, nil, false)
 		cb.NewClosureWith(sig, gogen.AutoLambdaLoop).BodyStart(pkg).
-			Return(0).
-			End(source("foo", 5, 1))
+			Return(0, source("foo", 5, 2)).
+			End()
+		cb.End()
+	})
+	codeErrorTest(t, `./foo.gop:6:1: can't use return/continue/break/goto in auto lambda`, func(pkg *gogen.Package) {
+		cb := pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg)
+		sig := types.NewSignatureType(nil, nil, nil, nil, nil, false)
+		cb.NewClosureWith(sig, gogen.AutoLambdaLoop).BodyStart(pkg).
+			Break(nil).
+			End(source("foo", 6, 1))
 		cb.End()
 	})
 }

func.go

@@ -100,18 +100,24 @@ func (p *Func) End(cb *CodeBuilder, src ast.Node) {
 		p.inlineClosureEnd(cb)
 		return
 	}
+
 	pkg := cb.pkg
 	checker := termChecker{cb.current.panicCalls}
 	fnBody, flows := cb.endFuncBody(p.old)
-	if flows != 0 && p.cate != AutoLambdaNormal {
-		cb.handleCodeError(getSrcPos(src), getSrcEnd(src), cantUseFlowsInAutoLambda)
+	cate := p.cate
+	if cate != AutoLambdaNormal {
+		if flows != 0 {
+			cb.handleCodeError(getSrcPos(src), getSrcEnd(src), cantUseFlowsInAutoLambda)
+		} else {
+			fnBody = return0IfNeeded(fnBody)
+		}
 	}
 	body := &target.BlockStmt{List: fnBody}
 	t := p.Type().(*types.Signature)
 
 	// Check for missing return at the closing brace position.
 	// For FuncDecl/FuncLit/BlockStmt, End() returns Rbrace+1, so End()-1 is the Rbrace position.
-	if t.Results().Len() > 0 && !checker.isTerminating(body, "") {
+	if cate == AutoLambdaNormal && t.Results().Len() > 0 && !checker.isTerminating(body, "") {
 		pos, end := token.NoPos, token.NoPos
 		if src != nil {
 			end = src.End()

package_test.go

@@ -3787,6 +3787,45 @@ func main() {
 `)
 }
 
+func TestAutoLambda1(t *testing.T) {
+	pkg := newMainPackage()
+	results := types.NewTuple(types.NewVar(0, pkg.Types, "", types.Typ[types.Int]))
+	sig := types.NewSignatureType(nil, nil, nil, nil, results, false)
+	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).
+		NewClosureWith(sig, gogen.AutoLambdaLoop).BodyStart(pkg).
+		End().Call(0).EndStmt().
+		End()
+	domTest(t, pkg, `package main
+
+func main() {
+	func() int {
+		return 0
+	}()
+}
+`)
+}
+
+func TestAutoLambda2(t *testing.T) {
+	pkg := newMainPackage()
+	results := types.NewTuple(types.NewVar(0, pkg.Types, "", types.Typ[types.Int]))
+	sig := types.NewSignatureType(nil, nil, nil, nil, results, false)
+	pkg.NewFunc(nil, "main", nil, nil, false).BodyStart(pkg).
+		NewClosureWith(sig, gogen.AutoLambdaLoop).BodyStart(pkg).
+		For().None().Then().End().
+		End().Call(0).EndStmt().
+		End()
+	domTest(t, pkg, `package main
+
+func main() {
+	func() int {
+		for {
+		}
+		return 0
+	}()
+}
+`)
+}
+
 func TestClosure(t *testing.T) {
 	pkg := newMainPackage()
 	fmt := pkg.Import("fmt")

util_gengo.go

@@ -1022,6 +1022,21 @@ func buildTypeForCallExpr(pkg *Package, T types.Type) ast.Expr {
 	}
 }
 
+func return0IfNeeded(stmts []ast.Stmt) []ast.Stmt {
+	var hasReturn bool
+	if len(stmts) > 0 {
+		_, hasReturn = stmts[len(stmts)-1].(*ast.ReturnStmt)
+	}
+	if !hasReturn {
+		stmts = append(stmts, &ast.ReturnStmt{
+			Results: []ast.Expr{
+				&ast.BasicLit{Kind: token.INT, Value: "0"},
+			},
+		})
+	}
+	return stmts
+}
+
 // ----------------------------------------------------------------------------
 
 func newIncDecStmt(x ast.Expr, tok token.Token) *ast.IncDecStmt {

util_genjs.go

@@ -216,6 +216,10 @@ func buildTypeForCallExpr(pkg *Package, T types.Type) js.Expr {
 	panic("todo buildTypeForCallExpr")
 }
 
+func return0IfNeeded(stmts []js.Stmt) []js.Stmt {
+	panic("todo return0IfNeeded")
+}
+
 // ----------------------------------------------------------------------------
 
 func newIncDecStmt(x js.Expr, tok token.Token) js.Stmt {