Merge pull request #29053 from Microsoft/fixDestructuringControlFlow

Fix destructuring control flow analysis

Author: ahejlsberg

src/compiler/checker.ts

@@ -1644,14 +1644,6 @@
         "category": "Error",
         "code": 2458
     },
-    "Type '{0}' has no property '{1}' and no string index signature.": {
-        "category": "Error",
-        "code": 2459
-    },
-    "Type '{0}' has no property '{1}'.": {
-        "category": "Error",
-        "code": 2460
-    },
     "Type '{0}' is not an array type.": {
         "category": "Error",
         "code": 2461
@@ -1768,7 +1760,7 @@
         "category": "Error",
         "code": 2492
     },
-    "Tuple type '{0}' with length '{1}' cannot be assigned to tuple with length '{2}'.": {
+    "Tuple type '{0}' of length '{1}' has no element at index '{2}'.": {
         "category": "Error",
         "code": 2493
     },

src/compiler/diagnosticMessages.json

@@ -1745,6 +1745,9 @@ namespace ts {
     export type EntityNameExpression = Identifier | PropertyAccessEntityNameExpression;
     export type EntityNameOrEntityNameExpression = EntityName | EntityNameExpression;
 
+    /* @internal */
+    export type AccessExpression = PropertyAccessExpression | ElementAccessExpression;
+
     export interface PropertyAccessExpression extends MemberExpression, NamedDeclaration {
         kind: SyntaxKind.PropertyAccessExpression;
         expression: LeftHandSideExpression;

src/compiler/types.ts

@@ -4590,6 +4590,10 @@ namespace ts {
             || kind === SyntaxKind.JSDocFunctionType
             || kind === SyntaxKind.JSDocVariadicType;
     }
+
+    export function isAccessExpression(node: Node): node is AccessExpression {
+        return node.kind === SyntaxKind.PropertyAccessExpression || node.kind === SyntaxKind.ElementAccessExpression;
+    }
 }
 
 namespace ts {

src/compiler/utilities.ts

@@ -1,15 +1,15 @@
-tests/cases/conformance/statements/for-ofStatements/ES5For-of31.ts(3,8): error TS2459: Type 'undefined' has no property 'a' and no string index signature.
-tests/cases/conformance/statements/for-ofStatements/ES5For-of31.ts(3,18): error TS2459: Type 'undefined' has no property 'b' and no string index signature.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of31.ts(3,8): error TS2339: Property 'a' does not exist on type 'undefined'.
+tests/cases/conformance/statements/for-ofStatements/ES5For-of31.ts(3,18): error TS2339: Property 'b' does not exist on type 'undefined'.
 
 
 ==== tests/cases/conformance/statements/for-ofStatements/ES5For-of31.ts (2 errors) ====
     var a: string, b: number;
 
     for ({ a: b = 1, b: a = ""} of []) {
            ~
-!!! error TS2459: Type 'undefined' has no property 'a' and no string index signature.
+!!! error TS2339: Property 'a' does not exist on type 'undefined'.
                      ~
-!!! error TS2459: Type 'undefined' has no property 'b' and no string index signature.
+!!! error TS2339: Property 'b' does not exist on type 'undefined'.
         a;
         b;
     }

tests/baselines/reference/ES5For-of31.errors.txt

@@ -1,7 +1,5 @@
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,12): error TS2493: Tuple type '[string, number]' with length '2' cannot be assigned to tuple with length '3'.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(16,12): error TS2460: Type 'StrNum' has no property '2'.
+tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(15,12): error TS2493: Tuple type '[string, number]' of length '2' has no element at index '2'.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,5): error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
-tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(17,12): error TS2460: Type '{ 0: string; 1: number; length: 2; }' has no property '2'.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(18,5): error TS2741: Property '2' is missing in type '[string, number]' but required in type '[number, number, number]'.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(19,5): error TS2741: Property '2' is missing in type 'StrNum' but required in type '[number, number, number]'.
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(20,5): error TS2740: Type '{ 0: string; 1: number; length: 2; }' is missing the following properties from type '[number, number, number]': 2, pop, push, concat, and 16 more.
@@ -30,7 +28,7 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(31,5): error
 tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(32,5): error TS2740: Type '{ 0: string; 1: number; length: 2; }' is missing the following properties from type '[number, string]': pop, push, concat, join, and 15 more.
 
 
-==== tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts (19 errors) ====
+==== tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts (17 errors) ====
     interface StrNum extends Array<string|number> {
         0: string;
         1: number;
@@ -47,15 +45,11 @@ tests/cases/conformance/types/tuple/arityAndOrderCompatibility01.ts(32,5): error
 
     var [a, b, c] = x;
                ~
-!!! error TS2493: Tuple type '[string, number]' with length '2' cannot be assigned to tuple with length '3'.
+!!! error TS2493: Tuple type '[string, number]' of length '2' has no element at index '2'.
     var [d, e, f] = y;
-               ~
-!!! error TS2460: Type 'StrNum' has no property '2'.
     var [g, h, i] = z;
         ~~~~~~~~~
 !!! error TS2461: Type '{ 0: string; 1: number; length: 2; }' is not an array type.
-               ~
-!!! error TS2460: Type '{ 0: string; 1: number; length: 2; }' has no property '2'.
     var j1: [number, number, number] = x;
         ~~
 !!! error TS2741: Property '2' is missing in type '[string, number]' but required in type '[number, number, number]'.

tests/baselines/reference/arityAndOrderCompatibility01.errors.txt

@@ -32,18 +32,18 @@ var z: {
 var [a, b, c] = x;
 >a : string
 >b : number
->c : any
+>c : undefined
 >x : [string, number]
 
 var [d, e, f] = y;
 >d : string
 >e : number
->f : any
+>f : string | number
 >y : StrNum
 
 var [g, h, i] = z;
->g : string
->h : number
+>g : any
+>h : any
 >i : any
 >z : { 0: string; 1: number; length: 2; }
 

tests/baselines/reference/arityAndOrderCompatibility01.types

@@ -1,7 +1,7 @@
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(22,13): error TS2339: Property '2' does not exist on type '[(x: number) => string, (x: number) => number]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(23,13): error TS2339: Property '2' does not exist on type '[E1, E2]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(24,13): error TS2339: Property '2' does not exist on type '[number, any]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(25,13): error TS2339: Property '3' does not exist on type '[E1, E2, number]'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(22,13): error TS2493: Tuple type '[(x: number) => string, (x: number) => number]' of length '2' has no element at index '2'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(23,13): error TS2493: Tuple type '[E1, E2]' of length '2' has no element at index '2'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(24,13): error TS2493: Tuple type '[number, any]' of length '2' has no element at index '2'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts(25,13): error TS2493: Tuple type '[E1, E2, number]' of length '3' has no element at index '3'.
 
 
 ==== tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple.ts (4 errors) ====
@@ -28,13 +28,13 @@ tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfT
     t4 = [E1.one, E2.two, 20];
     var e1 = t1[2];  // {}
                 ~
-!!! error TS2339: Property '2' does not exist on type '[(x: number) => string, (x: number) => number]'.
+!!! error TS2493: Tuple type '[(x: number) => string, (x: number) => number]' of length '2' has no element at index '2'.
     var e2 = t2[2];  // {}
                 ~
-!!! error TS2339: Property '2' does not exist on type '[E1, E2]'.
+!!! error TS2493: Tuple type '[E1, E2]' of length '2' has no element at index '2'.
     var e3 = t3[2];  // any
                 ~
-!!! error TS2339: Property '2' does not exist on type '[number, any]'.
+!!! error TS2493: Tuple type '[number, any]' of length '2' has no element at index '2'.
     var e4 = t4[3];  // number
                 ~
-!!! error TS2339: Property '3' does not exist on type '[E1, E2, number]'.
+!!! error TS2493: Tuple type '[E1, E2, number]' of length '3' has no element at index '3'.

tests/baselines/reference/bestCommonTypeOfTuple.errors.txt

@@ -1,8 +1,8 @@
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(17,14): error TS2339: Property '4' does not exist on type '[C, base]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(18,14): error TS2339: Property '4' does not exist on type '[C, D]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(19,14): error TS2339: Property '4' does not exist on type '[C1, D1]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(20,14): error TS2339: Property '2' does not exist on type '[base1, C1]'.
-tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(21,14): error TS2339: Property '2' does not exist on type '[C1, F]'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(17,14): error TS2493: Tuple type '[C, base]' of length '2' has no element at index '4'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(18,14): error TS2493: Tuple type '[C, D]' of length '2' has no element at index '4'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(19,14): error TS2493: Tuple type '[C1, D1]' of length '2' has no element at index '4'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(20,14): error TS2493: Tuple type '[base1, C1]' of length '2' has no element at index '2'.
+tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts(21,14): error TS2493: Tuple type '[C1, F]' of length '2' has no element at index '2'.
 
 
 ==== tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfTuple2.ts (5 errors) ====
@@ -24,17 +24,17 @@ tests/cases/conformance/types/typeRelationships/bestCommonType/bestCommonTypeOfT
 
     var e11 = t1[4]; // base
                  ~
-!!! error TS2339: Property '4' does not exist on type '[C, base]'.
+!!! error TS2493: Tuple type '[C, base]' of length '2' has no element at index '4'.
     var e21 = t2[4]; // {}
                  ~
-!!! error TS2339: Property '4' does not exist on type '[C, D]'.
+!!! error TS2493: Tuple type '[C, D]' of length '2' has no element at index '4'.
     var e31 = t3[4]; // C1
                  ~
-!!! error TS2339: Property '4' does not exist on type '[C1, D1]'.
+!!! error TS2493: Tuple type '[C1, D1]' of length '2' has no element at index '4'.
     var e41 = t4[2]; // base1
                  ~
-!!! error TS2339: Property '2' does not exist on type '[base1, C1]'.
+!!! error TS2493: Tuple type '[base1, C1]' of length '2' has no element at index '2'.
     var e51 = t5[2]; // {}
                  ~
-!!! error TS2339: Property '2' does not exist on type '[C1, F]'.
+!!! error TS2493: Tuple type '[C1, F]' of length '2' has no element at index '2'.
 

tests/baselines/reference/bestCommonTypeOfTuple2.errors.txt

@@ -6,7 +6,7 @@ tests/cases/conformance/types/tuple/castingTuple.ts(14,15): error TS2352: Conver
 tests/cases/conformance/types/tuple/castingTuple.ts(15,14): error TS2352: Conversion of type '[number, string]' to type '[number, string, boolean]' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
 tests/cases/conformance/types/tuple/castingTuple.ts(18,21): error TS2352: Conversion of type '[C, D]' to type '[C, D, A]' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
   Property '2' is missing in type '[C, D]' but required in type '[C, D, A]'.
-tests/cases/conformance/types/tuple/castingTuple.ts(20,33): error TS2339: Property '5' does not exist on type '[C, D, A]'.
+tests/cases/conformance/types/tuple/castingTuple.ts(20,33): error TS2493: Tuple type '[C, D, A]' of length '3' has no element at index '5'.
 tests/cases/conformance/types/tuple/castingTuple.ts(30,10): error TS2352: Conversion of type '[number, string]' to type '[number, number]' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
   Type 'string' is not comparable to type 'number'.
 tests/cases/conformance/types/tuple/castingTuple.ts(31,10): error TS2352: Conversion of type '[C, D]' to type '[A, I]' may be a mistake because neither type sufficiently overlaps with the other. If this was intentional, convert the expression to 'unknown' first.
@@ -49,7 +49,7 @@ tests/cases/conformance/types/tuple/castingTuple.ts(33,1): error TS2304: Cannot
     var eleFromCDA1 = classCDATuple[2]; // A
     var eleFromCDA2 = classCDATuple[5]; // C | D | A
                                     ~
-!!! error TS2339: Property '5' does not exist on type '[C, D, A]'.
+!!! error TS2493: Tuple type '[C, D, A]' of length '3' has no element at index '5'.
     var t10: [E1, E2] = [E1.one, E2.one];
     var t11 = <[number, number]>t10;
     var array1 = <{}[]>emptyObjTuple;