Merge pull request microsoft#12177 from Microsoft/error-on-non-identifier-rest-in-destructuring-assignment

sandersn · web-flow · commit 1bc4ab08504e · 2016-11-11T09:21:07.000-08:00
Error on non identifier rest in destructuring assignment
diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
@@ -13941,7 +13941,12 @@ namespace ts {
                     error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(objectLiteralType), declarationNameToString(name));
                 }
             }
-            else if (property.kind !== SyntaxKind.SpreadAssignment) {
+            else if (property.kind === SyntaxKind.SpreadAssignment) {
+                if (property.expression.kind !== SyntaxKind.Identifier) {
+                    error(property.expression, Diagnostics.An_object_rest_element_must_be_an_identifier);
+                }
+            }
+            else {
                 error(property, Diagnostics.Property_assignment_expected);
             }
         }
diff --git a/src/compiler/diagnosticMessages.json b/src/compiler/diagnosticMessages.json
@@ -1991,6 +1991,10 @@
         "category": "Error",
         "code": 2700
     },
+    "An object rest element must be an identifier.": {
+        "category": "Error",
+        "code": 2701
+    },
 
     "Import declaration '{0}' is using private name '{1}'.": {
         "category": "Error",
diff --git a/src/compiler/transformers/destructuring.ts b/src/compiler/transformers/destructuring.ts
@@ -328,8 +328,9 @@ namespace ts {
                         bindingElements.push(p);
                     }
                 }
-                else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadAssignment) {
-                    Debug.assert((p as SpreadAssignment).expression.kind === SyntaxKind.Identifier);
+                else if (i === properties.length - 1 &&
+                         p.kind === SyntaxKind.SpreadAssignment &&
+                         p.expression.kind === SyntaxKind.Identifier) {
                     if (bindingElements.length) {
                         emitRestAssignment(bindingElements, value, location, target);
                         bindingElements = [];
diff --git a/tests/baselines/reference/objectRestNegative.errors.txt b/tests/baselines/reference/objectRestNegative.errors.txt
@@ -1,9 +1,10 @@
 tests/cases/conformance/types/rest/objectRestNegative.ts(2,10): error TS2462: A rest element must be last in a destructuring pattern
 tests/cases/conformance/types/rest/objectRestNegative.ts(3,31): error TS2462: A rest element must be last in a destructuring pattern
 tests/cases/conformance/types/rest/objectRestNegative.ts(6,17): error TS2700: Rest types may only be created from object types.
+tests/cases/conformance/types/rest/objectRestNegative.ts(11,9): error TS2701: An object rest element must be an identifier.
 
 
-==== tests/cases/conformance/types/rest/objectRestNegative.ts (3 errors) ====
+==== tests/cases/conformance/types/rest/objectRestNegative.ts (4 errors) ====
     let o = { a: 1, b: 'no' };
     var { ...mustBeLast, a } = o;
              ~~~~~~~~~~
@@ -18,4 +19,9 @@ tests/cases/conformance/types/rest/objectRestNegative.ts(6,17): error TS2700: Re
 !!! error TS2700: Rest types may only be created from object types.
         return rest;
     }
+    
+    let rest: { b: string }
+    ({a, ...rest.b + rest.b} = o);
+            ~~~~~~~~~~~~~~~
+!!! error TS2701: An object rest element must be an identifier.
     
diff --git a/tests/baselines/reference/objectRestNegative.js b/tests/baselines/reference/objectRestNegative.js
@@ -7,6 +7,9 @@ function generic<T extends { x, y }>(t: T) {
     let { x, ...rest } = t;
     return rest;
 }
+
+let rest: { b: string }
+({a, ...rest.b + rest.b} = o);
 
 
 //// [objectRestNegative.js]
@@ -25,3 +28,5 @@ function generic(t) {
     var x = t.x, rest = __rest(t, ["x"]);
     return rest;
 }
+var rest;
+(a = o.a, o, o);
diff --git a/tests/cases/conformance/types/rest/objectRestNegative.ts b/tests/cases/conformance/types/rest/objectRestNegative.ts
@@ -6,3 +6,6 @@ function generic<T extends { x, y }>(t: T) {
     let { x, ...rest } = t;
     return rest;
 }
+
+let rest: { b: string }
+({a, ...rest.b + rest.b} = o);

Original file line number	Diff line number	Diff line change
`@@ -13941,7 +13941,12 @@ namespace ts {`
`13941`	`13941`	`error(name, Diagnostics.Type_0_has_no_property_1_and_no_string_index_signature, typeToString(objectLiteralType), declarationNameToString(name));`
`13942`	`13942`	`}`
`13943`	`13943`	`}`
`13944`		`- else if (property.kind !== SyntaxKind.SpreadAssignment) {`
	`13944`	`+ else if (property.kind === SyntaxKind.SpreadAssignment) {`
	`13945`	`+ if (property.expression.kind !== SyntaxKind.Identifier) {`
	`13946`	`+ error(property.expression, Diagnostics.An_object_rest_element_must_be_an_identifier);`
	`13947`	`+ }`
	`13948`	`+ }`
	`13949`	`+ else {`
`13945`	`13950`	`error(property, Diagnostics.Property_assignment_expected);`
`13946`	`13951`	`}`
`13947`	`13952`	`}`
Original file line number	Diff line number	Diff line change
`@@ -328,8 +328,9 @@ namespace ts {`
`328`	`328`	`bindingElements.push(p);`
`329`	`329`	`}`
`330`	`330`	`}`
`331`		`- else if (i === properties.length - 1 && p.kind === SyntaxKind.SpreadAssignment) {`
`332`		`- Debug.assert((p as SpreadAssignment).expression.kind === SyntaxKind.Identifier);`
	`331`	`+ else if (i === properties.length - 1 &&`
	`332`	`+ p.kind === SyntaxKind.SpreadAssignment &&`
	`333`	`+ p.expression.kind === SyntaxKind.Identifier) {`
`333`	`334`	`if (bindingElements.length) {`
`334`	`335`	`emitRestAssignment(bindingElements, value, location, target);`
`335`	`336`	`bindingElements = [];`
Original file line number	Diff line number	Diff line change
`@@ -7,6 +7,9 @@ function generic<T extends { x, y }>(t: T) {`
`7`	`7`	`let { x, ...rest } = t;`
`8`	`8`	`return rest;`
`9`	`9`	`}`
	`10`	`+`
	`11`	`+let rest: { b: string }`
	`12`	`+({a, ...rest.b + rest.b} = o);`
`10`	`13`
`11`	`14`
`12`	`15`	`//// [objectRestNegative.js]`
`@@ -25,3 +28,5 @@ function generic(t) {`
`25`	`28`	`var x = t.x, rest = __rest(t, ["x"]);`
`26`	`29`	`return rest;`
`27`	`30`	`}`
	`31`	`+var rest;`
	`32`	`+(a = o.a, o, o);`
Original file line number	Diff line number	Diff line change
`@@ -6,3 +6,6 @@ function generic<T extends { x, y }>(t: T) {`
`6`	`6`	`let { x, ...rest } = t;`
`7`	`7`	`return rest;`
`8`	`8`	`}`
	`9`	`+`
	`10`	`+let rest: { b: string }`
	`11`	`+({a, ...rest.b + rest.b} = o);`