Fix crash when checking invalid object rest (#31530)

src/compiler/checker.ts

@@ -23370,14 +23370,16 @@ namespace ts {
             if (strictNullChecks && properties.length === 0) {
                 return checkNonNullType(sourceType, node);
             }
-            for (const p of properties) {
-                checkObjectLiteralDestructuringPropertyAssignment(sourceType, p, properties, rightIsThis);
+            for (let i = 0; i < properties.length; i++) {
+                checkObjectLiteralDestructuringPropertyAssignment(node, sourceType, i, properties, rightIsThis);
             }
             return sourceType;
         }
 
         /** Note: If property cannot be a SpreadAssignment, then allProperties does not need to be provided */
-        function checkObjectLiteralDestructuringPropertyAssignment(objectLiteralType: Type, property: ObjectLiteralElementLike, allProperties?: NodeArray<ObjectLiteralElementLike>, rightIsThis = false) {
+        function checkObjectLiteralDestructuringPropertyAssignment(node: ObjectLiteralExpression, objectLiteralType: Type, propertyIndex: number, allProperties?: NodeArray<ObjectLiteralElementLike>, rightIsThis = false) {
+            const properties = node.properties;
+            const property = properties[propertyIndex];
             if (property.kind === SyntaxKind.PropertyAssignment || property.kind === SyntaxKind.ShorthandPropertyAssignment) {
                 const name = property.name;
                 const exprType = getLiteralTypeFromPropertyName(name);
@@ -23394,18 +23396,25 @@ namespace ts {
                 return checkDestructuringAssignment(property.kind === SyntaxKind.ShorthandPropertyAssignment ? property : property.initializer, type);
             }
             else if (property.kind === SyntaxKind.SpreadAssignment) {
-                if (languageVersion < ScriptTarget.ESNext) {
-                    checkExternalEmitHelpers(property, ExternalEmitHelpers.Rest);
+                if (propertyIndex < properties.length - 1) {
+                    error(property, Diagnostics.A_rest_element_must_be_last_in_a_destructuring_pattern);
                 }
-                const nonRestNames: PropertyName[] = [];
-                if (allProperties) {
-                    for (let i = 0; i < allProperties.length - 1; i++) {
-                        nonRestNames.push(allProperties[i].name!);
+                else {
+                    if (languageVersion < ScriptTarget.ESNext) {
+                        checkExternalEmitHelpers(property, ExternalEmitHelpers.Rest);
+                    }
+                    const nonRestNames: PropertyName[] = [];
+                    if (allProperties) {
+                        for (const otherProperty of allProperties) {
+                            if (!isSpreadAssignment(otherProperty)) {
+                                nonRestNames.push(otherProperty.name);
+                            }
+                        }
                     }
+                    const type = getRestType(objectLiteralType, nonRestNames, objectLiteralType.symbol);
+                    checkGrammarForDisallowedTrailingComma(allProperties, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
+                    return checkDestructuringAssignment(property.expression, type);
                 }
-                const type = getRestType(objectLiteralType, nonRestNames, objectLiteralType.symbol);
-                checkGrammarForDisallowedTrailingComma(allProperties, Diagnostics.A_rest_parameter_or_binding_pattern_may_not_have_a_trailing_comma);
-                return checkDestructuringAssignment(property.expression, type);
             }
             else {
                 error(property, Diagnostics.Property_assignment_expected);
@@ -29964,8 +29973,10 @@ namespace ts {
             // If this is from nested object binding pattern
             //     for ({ skills: { primary, secondary } } = multiRobot, i = 0; i < 1; i++) {
             if (expr.parent.kind === SyntaxKind.PropertyAssignment) {
-                const typeOfParentObjectLiteral = getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(<Expression>expr.parent.parent);
-                return checkObjectLiteralDestructuringPropertyAssignment(typeOfParentObjectLiteral || errorType, <ObjectLiteralElementLike>expr.parent)!; // TODO: GH#18217
+                const node = cast(expr.parent.parent, isObjectLiteralExpression);
+                const typeOfParentObjectLiteral = getTypeOfArrayLiteralOrObjectLiteralDestructuringAssignment(node);
+                const propertyIndex = indexOfNode(node.properties, expr.parent);
+                return checkObjectLiteralDestructuringPropertyAssignment(node, typeOfParentObjectLiteral || errorType, propertyIndex)!; // TODO: GH#18217
             }
             // Array literal assignment - array destructuring pattern
             Debug.assert(expr.parent.kind === SyntaxKind.ArrayLiteralExpression);

tests/baselines/reference/objectRestPropertyMustBeLast.errors.txt

@@ -0,0 +1,21 @@
+tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts(1,9): error TS2462: A rest element must be last in a destructuring pattern.
+tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts(2,3): error TS2462: A rest element must be last in a destructuring pattern.
+tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts(4,9): error TS2462: A rest element must be last in a destructuring pattern.
+tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts(5,3): error TS2462: A rest element must be last in a destructuring pattern.
+
+
+==== tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts (4 errors) ====
+    var {...a, x } = { x: 1 };    // Error, rest must be last property
+            ~
+!!! error TS2462: A rest element must be last in a destructuring pattern.
+    ({...a, x } = { x: 1 });      // Error, rest must be last property
+      ~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern.
+
+    var {...a, x, ...b } = { x: 1 };    // Error, rest must be last property
+            ~
+!!! error TS2462: A rest element must be last in a destructuring pattern.
+    ({...a, x, ...b } = { x: 1 });      // Error, rest must be last property
+      ~~~~
+!!! error TS2462: A rest element must be last in a destructuring pattern.
+

tests/baselines/reference/objectRestPropertyMustBeLast.js

@@ -0,0 +1,25 @@
+//// [objectRestPropertyMustBeLast.ts]
+var {...a, x } = { x: 1 };    // Error, rest must be last property
+({...a, x } = { x: 1 });      // Error, rest must be last property
+
+var {...a, x, ...b } = { x: 1 };    // Error, rest must be last property
+({...a, x, ...b } = { x: 1 });      // Error, rest must be last property
+
+
+//// [objectRestPropertyMustBeLast.js]
+var __rest = (this && this.__rest) || function (s, e) {
+    var t = {};
+    for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p) && e.indexOf(p) < 0)
+        t[p] = s[p];
+    if (s != null && typeof Object.getOwnPropertySymbols === "function")
+        for (var i = 0, p = Object.getOwnPropertySymbols(s); i < p.length; i++) {
+            if (e.indexOf(p[i]) < 0 && Object.prototype.propertyIsEnumerable.call(s, p[i]))
+                t[p[i]] = s[p[i]];
+        }
+    return t;
+};
+var _a, _b;
+var _c = { x: 1 }, x = _c.x; // Error, rest must be last property
+(_a = { x: 1 }, (x = _a.x, _a)); // Error, rest must be last property
+var _d = { x: 1 }, x = _d.x, b = __rest(_d, ["a", "x"]); // Error, rest must be last property
+(_b = { x: 1 }, (x = _b.x, _b), b = __rest(_b, ["x"])); // Error, rest must be last property

tests/baselines/reference/objectRestPropertyMustBeLast.symbols

@@ -0,0 +1,23 @@
+=== tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts ===
+var {...a, x } = { x: 1 };    // Error, rest must be last property
+>a : Symbol(a, Decl(objectRestPropertyMustBeLast.ts, 0, 5), Decl(objectRestPropertyMustBeLast.ts, 3, 5))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 0, 10), Decl(objectRestPropertyMustBeLast.ts, 3, 10))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 0, 18))
+
+({...a, x } = { x: 1 });      // Error, rest must be last property
+>a : Symbol(a, Decl(objectRestPropertyMustBeLast.ts, 0, 5), Decl(objectRestPropertyMustBeLast.ts, 3, 5))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 1, 7))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 1, 15))
+
+var {...a, x, ...b } = { x: 1 };    // Error, rest must be last property
+>a : Symbol(a, Decl(objectRestPropertyMustBeLast.ts, 0, 5), Decl(objectRestPropertyMustBeLast.ts, 3, 5))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 0, 10), Decl(objectRestPropertyMustBeLast.ts, 3, 10))
+>b : Symbol(b, Decl(objectRestPropertyMustBeLast.ts, 3, 13))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 3, 24))
+
+({...a, x, ...b } = { x: 1 });      // Error, rest must be last property
+>a : Symbol(a, Decl(objectRestPropertyMustBeLast.ts, 0, 5), Decl(objectRestPropertyMustBeLast.ts, 3, 5))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 4, 7))
+>b : Symbol(b, Decl(objectRestPropertyMustBeLast.ts, 3, 13))
+>x : Symbol(x, Decl(objectRestPropertyMustBeLast.ts, 4, 21))
+

tests/baselines/reference/objectRestPropertyMustBeLast.types

@@ -0,0 +1,37 @@
+=== tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts ===
+var {...a, x } = { x: 1 };    // Error, rest must be last property
+>a : {}
+>x : number
+>{ x: 1 } : { x: number; }
+>x : number
+>1 : 1
+
+({...a, x } = { x: 1 });      // Error, rest must be last property
+>({...a, x } = { x: 1 }) : { x: number; }
+>{...a, x } = { x: 1 } : { x: number; }
+>{...a, x } : { x: number; }
+>a : {}
+>x : number
+>{ x: 1 } : { x: number; }
+>x : number
+>1 : 1
+
+var {...a, x, ...b } = { x: 1 };    // Error, rest must be last property
+>a : {}
+>x : number
+>b : {}
+>{ x: 1 } : { x: number; }
+>x : number
+>1 : 1
+
+({...a, x, ...b } = { x: 1 });      // Error, rest must be last property
+>({...a, x, ...b } = { x: 1 }) : { x: number; }
+>{...a, x, ...b } = { x: 1 } : { x: number; }
+>{...a, x, ...b } : { x: number; }
+>a : {}
+>x : number
+>b : {}
+>{ x: 1 } : { x: number; }
+>x : number
+>1 : 1
+

tests/cases/conformance/types/rest/objectRestPropertyMustBeLast.ts

@@ -0,0 +1,5 @@
+var {...a, x } = { x: 1 };    // Error, rest must be last property
+({...a, x } = { x: 1 });      // Error, rest must be last property
+
+var {...a, x, ...b } = { x: 1 };    // Error, rest must be last property
+({...a, x, ...b } = { x: 1 });      // Error, rest must be last property