Refactor logical assignment

src/compiler/binder.ts

@@ -1047,24 +1047,9 @@ namespace ts {
             }
         }
 
-        function isLogicalAssignmentExpressioin(node: Node) {
-            while (true) {
-                if (isParenthesizedExpression(node)) {
-                    node = node.expression;
-                }
-                else {
-                    return isBinaryExpression(node) && isLogicalAssignmentOperator(node.operatorToken.kind);
-                }
-            }
-        }
-
-        function isTopLevelLogicalAssignmentExpression(node: Node): boolean {
-            while (isParenthesizedExpression(node.parent)) {
-                node = node.parent;
-            }
-            return !isStatementCondition(node) &&
-                !isLogicalAssignmentExpressioin(node.parent) &&
-                !(isOptionalChain(node.parent) && node.parent.expression === node);
+        function isLogicalAssignmentExpression(node: Node) {
+            node = skipParentheses(node);
+            return isBinaryExpression(node) && isLogicalOrCoalescingAssignmentOperator(node.operatorToken.kind);
         }
 
         function isTopLevelLogicalExpression(node: Node): boolean {
@@ -1073,6 +1058,7 @@ namespace ts {
                 node = node.parent;
             }
             return !isStatementCondition(node) &&
+                !isLogicalAssignmentExpression(node.parent) &&
                 !isLogicalExpression(node.parent) &&
                 !(isOptionalChain(node.parent) && node.parent.expression === node);
         }
@@ -1089,7 +1075,7 @@ namespace ts {
 
         function bindCondition(node: Expression | undefined, trueTarget: FlowLabel, falseTarget: FlowLabel) {
             doWithConditionalBranches(bind, node, trueTarget, falseTarget);
-            if (!node || !isLogicalAssignmentExpressioin(node) && !isLogicalExpression(node) && !(isOptionalChain(node) && isOutermostOptionalChain(node))) {
+            if (!node || !isLogicalAssignmentExpression(node) && !isLogicalExpression(node) && !(isOptionalChain(node) && isOutermostOptionalChain(node))) {
                 addAntecedent(trueTarget, createFlowCondition(FlowFlags.TrueCondition, currentFlow, node));
                 addAntecedent(falseTarget, createFlowCondition(FlowFlags.FalseCondition, currentFlow, node));
             }
@@ -1189,24 +1175,6 @@ namespace ts {
             currentFlow = finishFlowLabel(postIfLabel);
         }
 
-        function bindLogicalAssignmentExpression(node: BinaryExpression, trueTarget: FlowLabel, falseTarget: FlowLabel) {
-            const preRightLabel = createBranchLabel();
-            if (node.operatorToken.kind === SyntaxKind.AmpersandAmpersandEqualsToken) {
-                bindCondition(node.left, preRightLabel, falseTarget);
-            }
-            else {
-                bindCondition(node.left, trueTarget, preRightLabel);
-            }
-            currentFlow = finishFlowLabel(preRightLabel);
-            bind(node.operatorToken);
-
-            doWithConditionalBranches(bind, node.right, trueTarget, falseTarget);
-            bindAssignmentTargetFlow(node.left);
-
-            addAntecedent(trueTarget, createFlowCondition(FlowFlags.TrueCondition, currentFlow, node));
-            addAntecedent(falseTarget, createFlowCondition(FlowFlags.FalseCondition, currentFlow, node));
-        }
-
         function bindReturnOrThrow(node: ReturnStatement | ThrowStatement): void {
             bind(node.expression);
             if (node.kind === SyntaxKind.ReturnStatement) {
@@ -1448,17 +1416,27 @@ namespace ts {
             }
         }
 
-        function bindLogicalExpression(node: BinaryExpression, trueTarget: FlowLabel, falseTarget: FlowLabel) {
+        function bindLogicalLikeExpression(node: BinaryExpression, trueTarget: FlowLabel, falseTarget: FlowLabel) {
             const preRightLabel = createBranchLabel();
-            if (node.operatorToken.kind === SyntaxKind.AmpersandAmpersandToken) {
+            if (node.operatorToken.kind === SyntaxKind.AmpersandAmpersandToken || node.operatorToken.kind === SyntaxKind.AmpersandAmpersandEqualsToken) {
                 bindCondition(node.left, preRightLabel, falseTarget);
             }
             else {
                 bindCondition(node.left, trueTarget, preRightLabel);
             }
             currentFlow = finishFlowLabel(preRightLabel);
             bind(node.operatorToken);
-            bindCondition(node.right, trueTarget, falseTarget);
+
+            if (isLogicalOrCoalescingAssignmentOperator(node.operatorToken.kind)) {
+                doWithConditionalBranches(bind, node.right, trueTarget, falseTarget);
+                bindAssignmentTargetFlow(node.left);
+
+                addAntecedent(trueTarget, createFlowCondition(FlowFlags.TrueCondition, currentFlow, node));
+                addAntecedent(falseTarget, createFlowCondition(FlowFlags.FalseCondition, currentFlow, node));
+            }
+            else {
+                bindCondition(node.right, trueTarget, falseTarget);
+            }
         }
 
         function bindPrefixUnaryExpressionFlow(node: PrefixUnaryExpression) {
@@ -1544,25 +1522,15 @@ namespace ts {
                         // TODO: bindLogicalExpression is recursive - if we want to handle deeply nested `&&` expressions
                         // we'll need to handle the `bindLogicalExpression` scenarios in this state machine, too
                         // For now, though, since the common cases are chained `+`, leaving it recursive is fine
-                        if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.BarBarToken || operator === SyntaxKind.QuestionQuestionToken) {
+                        if (operator === SyntaxKind.AmpersandAmpersandToken || operator === SyntaxKind.BarBarToken || operator === SyntaxKind.QuestionQuestionToken ||
+                            isLogicalOrCoalescingAssignmentOperator(operator)) {
                             if (isTopLevelLogicalExpression(node)) {
                                 const postExpressionLabel = createBranchLabel();
-                                bindLogicalExpression(node, postExpressionLabel, postExpressionLabel);
-                                currentFlow = finishFlowLabel(postExpressionLabel);
-                            }
-                            else {
-                                bindLogicalExpression(node, currentTrueTarget!, currentFalseTarget!);
-                            }
-                            completeNode();
-                        }
-                        else if(isLogicalAssignmentOperator(operator)) {
-                            if (isTopLevelLogicalAssignmentExpression(node)) {
-                                const postExpressionLabel = createBranchLabel();
-                                bindLogicalAssignmentExpression(node, postExpressionLabel, postExpressionLabel);
+                                bindLogicalLikeExpression(node, postExpressionLabel, postExpressionLabel);
                                 currentFlow = finishFlowLabel(postExpressionLabel);
                             }
                             else {
-                                bindLogicalAssignmentExpression(node, currentTrueTarget!, currentFalseTarget!);
+                                bindLogicalLikeExpression(node, currentTrueTarget!, currentFalseTarget!);
                             }
                             completeNode();
                         }
@@ -3656,7 +3624,7 @@ namespace ts {
         if (operatorTokenKind === SyntaxKind.QuestionQuestionToken) {
             transformFlags |= TransformFlags.AssertES2020;
         }
-        else if (isLogicalAssignmentOperator(operatorTokenKind)) {
+        else if (isLogicalOrCoalescingAssignmentOperator(operatorTokenKind)) {
             transformFlags |= TransformFlags.AssertESNext;
         }
         else if (operatorTokenKind === SyntaxKind.EqualsToken && leftKind === SyntaxKind.ObjectLiteralExpression) {

src/compiler/checker.ts

@@ -28596,7 +28596,7 @@ namespace ts {
                         getUnionType([removeDefinitelyFalsyTypes(leftType), rightType], UnionReduction.Subtype) :
                         leftType;
                     if (operator === SyntaxKind.BarBarEqualsToken) {
-                        checkAssignmentOperator(resultType);
+                        checkAssignmentOperator(rightType);
                     }
                     return resultType;
                 }
@@ -28606,7 +28606,7 @@ namespace ts {
                         getUnionType([getNonNullableType(leftType), rightType], UnionReduction.Subtype) :
                         leftType;
                     if (operator === SyntaxKind.QuestionQuestionEqualsToken) {
-                        checkAssignmentOperator(resultType);
+                        checkAssignmentOperator(rightType);
                     }
                     return resultType;
                 }

src/compiler/transformers/esnext.ts

@@ -18,7 +18,7 @@ namespace ts {
             switch (node.kind) {
                 case SyntaxKind.BinaryExpression:
                     const binaryExpression = <BinaryExpression>node;
-                    if (isLogicalAssignmentOperator(binaryExpression.operatorToken.kind)) {
+                    if (isLogicalOrCoalescingAssignmentOperator(binaryExpression.operatorToken.kind)) {
                         return transformLogicalAssignmentOperators(binaryExpression);
                     }
                     // falls through
@@ -29,7 +29,7 @@ namespace ts {
 
         function transformLogicalAssignmentOperators(binaryExpression: BinaryExpression): VisitResult<Node> {
             const operator = binaryExpression.operatorToken;
-            if (isCompoundAssignment(operator.kind) && isLogicalAssignmentOperator(operator.kind)) {
+            if (isCompoundAssignment(operator.kind) && isLogicalOrCoalescingAssignmentOperator(operator.kind)) {
                 const nonAssignmentOperator = getNonAssignmentOperatorForCompoundAssignment(operator.kind);
                 const left = visitNode(binaryExpression.left, visitor, isExpression);
                 const right = visitNode(binaryExpression.right, visitor, isExpression);

src/compiler/utilities.ts

@@ -2594,7 +2594,7 @@ namespace ts {
             switch (parent.kind) {
                 case SyntaxKind.BinaryExpression:
                     const binaryOperator = (<BinaryExpression>parent).operatorToken.kind;
-                    return isAssignmentOperator(binaryOperator) && !isLogicalAssignmentOperator(binaryOperator) && (<BinaryExpression>parent).left === node ?
+                    return isAssignmentOperator(binaryOperator) && !isLogicalOrCoalescingAssignmentOperator(binaryOperator) && (<BinaryExpression>parent).left === node ?
                         binaryOperator === SyntaxKind.EqualsToken ? AssignmentKind.Definite : AssignmentKind.Compound :
                         AssignmentKind.None;
                 case SyntaxKind.PrefixUnaryExpression:
@@ -3378,10 +3378,6 @@ namespace ts {
                 return 14;
             case SyntaxKind.AsteriskAsteriskToken:
                 return 15;
-            case SyntaxKind.BarBarEqualsToken:
-            case SyntaxKind.AmpersandAmpersandEqualsToken:
-            case SyntaxKind.QuestionQuestionEqualsToken:
-                return 16;
         }
 
         // -1 is lower than all other precedences.  Returning it will cause binary expression
@@ -4454,7 +4450,7 @@ namespace ts {
             || token === SyntaxKind.ExclamationToken;
     }
 
-    export function isLogicalAssignmentOperator(token: SyntaxKind): boolean {
+    export function isLogicalOrCoalescingAssignmentOperator(token: SyntaxKind): boolean {
         return token === SyntaxKind.BarBarEqualsToken
             || token === SyntaxKind.AmpersandAmpersandEqualsToken
             || token === SyntaxKind.QuestionQuestionEqualsToken;

src/services/codefixes/inferFromUsage.ts

@@ -785,12 +785,6 @@ namespace ts.codefix {
                     }
                     break;
 
-                case SyntaxKind.BarBarEqualsToken:
-                case SyntaxKind.QuestionQuestionEqualsToken:
-                case SyntaxKind.AmpersandAmpersandEqualsToken:
-                    // TODO: infer here
-                    break;
-
                 case SyntaxKind.AmpersandAmpersandToken:
                 case SyntaxKind.CommaToken:
                 case SyntaxKind.InstanceOfKeyword:

tests/baselines/reference/logicalAssignment7(target=es2015).errors.txt

@@ -1,29 +1,20 @@
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(2,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(6,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,5): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,40): error TS2345: Argument of type '100' is not assignable to parameter of type 'never'.
 
 
-==== tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts (5 errors) ====
+==== tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts (2 errors) ====
     function foo1(results: number[] | undefined, results1: number[] | undefined) {
         (results ||= results1 ||= []).push(100);
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
 
     function foo2(results: number[] | undefined, results1: number[] | undefined) {
         (results ??= results1 ??= []).push(100);
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
 
     function foo3(results: number[] | undefined, results1: number[] | undefined) {
         (results &&= results1 &&= []).push(100);
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2532: Object is possibly 'undefined'.
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
                                            ~~~
 !!! error TS2345: Argument of type '100' is not assignable to parameter of type 'never'.
     }

tests/baselines/reference/logicalAssignment7(target=es2015).js

@@ -14,12 +14,11 @@ function foo3(results: number[] | undefined, results1: number[] | undefined) {
 //// [logicalAssignment7.js]
 "use strict";
 function foo1(results, results1) {
-    (results || (results = results1) || (results || (results = results1) = [])).push(100);
+    (results || (results = results1 || (results1 = []))).push(100);
 }
 function foo2(results, results1) {
-    var _a;
-    ((_a = results !== null && results !== void 0 ? results : (results = results1)) !== null && _a !== void 0 ? _a : (results !== null && results !== void 0 ? results : (results = results1) = [])).push(100);
+    (results !== null && results !== void 0 ? results : (results = results1 !== null && results1 !== void 0 ? results1 : (results1 = []))).push(100);
 }
 function foo3(results, results1) {
-    (results && (results = results1) && (results && (results = results1) = [])).push(100);
+    (results && (results = results1 && (results1 = []))).push(100);
 }

tests/baselines/reference/logicalAssignment7(target=es2015).types

@@ -9,8 +9,8 @@ function foo1(results: number[] | undefined, results1: number[] | undefined) {
 >(results ||= results1 ||= []).push : (...items: number[]) => number
 >(results ||= results1 ||= []) : number[]
 >results ||= results1 ||= [] : number[]
->results ||= results1 : number[] | undefined
 >results : number[] | undefined
+>results1 ||= [] : number[]
 >results1 : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -27,8 +27,8 @@ function foo2(results: number[] | undefined, results1: number[] | undefined) {
 >(results ??= results1 ??= []).push : (...items: number[]) => number
 >(results ??= results1 ??= []) : number[]
 >results ??= results1 ??= [] : number[]
->results ??= results1 : number[] | undefined
 >results : number[] | undefined
+>results1 ??= [] : number[]
 >results1 : number[] | undefined
 >[] : never[]
 >push : (...items: number[]) => number
@@ -45,8 +45,8 @@ function foo3(results: number[] | undefined, results1: number[] | undefined) {
 >(results &&= results1 &&= []).push : (...items: never[]) => number
 >(results &&= results1 &&= []) : never[] | undefined
 >results &&= results1 &&= [] : never[] | undefined
->results &&= results1 : number[] | undefined
 >results : number[] | undefined
+>results1 &&= [] : never[] | undefined
 >results1 : number[] | undefined
 >[] : never[]
 >push : (...items: never[]) => number

tests/baselines/reference/logicalAssignment7(target=es2020).errors.txt

@@ -1,29 +1,20 @@
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(2,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(6,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,5): error TS2532: Object is possibly 'undefined'.
-tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,6): error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
 tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts(10,40): error TS2345: Argument of type '100' is not assignable to parameter of type 'never'.
 
 
-==== tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts (5 errors) ====
+==== tests/cases/conformance/esnext/logicalAssignment/logicalAssignment7.ts (2 errors) ====
     function foo1(results: number[] | undefined, results1: number[] | undefined) {
         (results ||= results1 ||= []).push(100);
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
 
     function foo2(results: number[] | undefined, results1: number[] | undefined) {
         (results ??= results1 ??= []).push(100);
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
     }
 
     function foo3(results: number[] | undefined, results1: number[] | undefined) {
         (results &&= results1 &&= []).push(100);
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 !!! error TS2532: Object is possibly 'undefined'.
-         ~~~~~~~~~~~~~~~~~~~~
-!!! error TS2364: The left-hand side of an assignment expression must be a variable or a property access.
                                            ~~~
 !!! error TS2345: Argument of type '100' is not assignable to parameter of type 'never'.
     }

tests/baselines/reference/logicalAssignment7(target=es2020).js

@@ -14,11 +14,11 @@ function foo3(results: number[] | undefined, results1: number[] | undefined) {
 //// [logicalAssignment7.js]
 "use strict";
 function foo1(results, results1) {
-    (results || (results = results1) || (results || (results = results1) = [])).push(100);
+    (results || (results = results1 || (results1 = []))).push(100);
 }
 function foo2(results, results1) {
-    (results ?? (results = results1) ?? (results ?? (results = results1) = [])).push(100);
+    (results ?? (results = results1 ?? (results1 = []))).push(100);
 }
 function foo3(results, results1) {
-    (results && (results = results1) && (results && (results = results1) = [])).push(100);
+    (results && (results = results1 && (results1 = []))).push(100);
 }