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Commit 63b83e7

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ahejlsbergahejlsberg
committed
Contextual typing of array literals is now based on the presence or absence
of numerically named properties and doesn't directly test for tuple types.
1 parent c0e802d commit 63b83e7
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3 files changed

+37-30Lines changed: 37 additions & 30 deletions

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‎src/compiler/checker.ts‎

Copy file name to clipboardExpand all lines: src/compiler/checker.ts
+18-17Lines changed: 18 additions & 17 deletions
Original file line numberDiff line numberDiff line change
@@ -3758,19 +3758,17 @@ module ts {
37583758
return undefined;
37593759
}
37603760

3761-
// In an array literal contextually typed by a type T, the contextual type of an element expression is the corresponding
3762-
// tuple element type in T, if one exists and T is a tuple type. Otherwise, it is the type of the numeric index signature
3763-
// in T, if one exists.
3761+
// In an array literal contextually typed by a type T, the contextual type of an element expression at index N is
3762+
// the type of the property with the numeric name N in T, if one exists. Otherwise, it is the type of the numeric
3763+
// index signature in T, if one exists.
37643764
function getContextualTypeForElementExpression(node: Expression): Type {
37653765
var arrayLiteral = <ArrayLiteral>node.parent;
37663766
var type = getContextualType(arrayLiteral);
37673767
if (type) {
3768-
if (type.flags & TypeFlags.Tuple) {
3769-
var index = indexOf(arrayLiteral.elements, node);
3770-
var prop = getPropertyOfType(type, "" + index);
3771-
if (prop) {
3772-
return getTypeOfSymbol(prop);
3773-
}
3768+
var index = indexOf(arrayLiteral.elements, node);
3769+
var prop = getPropertyOfType(type, "" + index);
3770+
if (prop) {
3771+
return getTypeOfSymbol(prop);
37743772
}
37753773
return getIndexTypeOfType(type, IndexKind.Number);
37763774
}
@@ -3837,21 +3835,24 @@ module ts {
38373835

38383836
function checkArrayLiteral(node: ArrayLiteral, contextualMapper?: TypeMapper): Type {
38393837
var contextualType = getContextualType(node);
3840-
var isTupleLiteral = contextualType && (contextualType.flags & TypeFlags.Tuple) !== 0;
3838+
var elements = node.elements;
38413839
var elementTypes: Type[] = [];
3842-
forEach(node.elements, element => {
3843-
var type = element.kind !== SyntaxKind.OmittedExpression ? checkExpression(element, contextualMapper) : undefinedType;
3844-
if (isTupleLiteral || !contains(elementTypes, type)) {
3845-
elementTypes.push(type);
3840+
var isTupleLiteral: boolean = false;
3841+
for (var i = 0; i < elements.length; i++) {
3842+
if (contextualType && getPropertyOfType(contextualType, "" + i)) {
3843+
isTupleLiteral = true;
38463844
}
3847-
});
3845+
var element = elements[i];
3846+
var type = element.kind !== SyntaxKind.OmittedExpression ? checkExpression(element, contextualMapper) : undefinedType;
3847+
elementTypes.push(type);
3848+
}
38483849
if (isTupleLiteral) {
38493850
return createTupleType(elementTypes);
38503851
}
38513852
var contextualElementType = contextualType && !isInferentialContext(contextualMapper) ? getIndexTypeOfType(contextualType, IndexKind.Number) : undefined;
3852-
var elementType = getBestCommonType(elementTypes, contextualElementType, true);
3853+
var elementType = getBestCommonType(uniqueElements(elementTypes), contextualElementType, true);
38533854
if (!elementType) {
3854-
elementType = elementTypes.length ? emptyObjectType : undefinedType;
3855+
elementType = elements.length ? emptyObjectType : undefinedType;
38553856
}
38563857
return createArrayType(elementType);
38573858
}
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‎src/compiler/core.ts‎

Copy file name to clipboardExpand all lines: src/compiler/core.ts
+16-10Lines changed: 16 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -19,8 +19,7 @@ module ts {
1919

2020
export function contains<T>(array: T[], value: T): boolean {
2121
if (array) {
22-
var len = array.length;
23-
for (var i = 0; i < len; i++) {
22+
for (var i = 0, len = array.length; i < len; i++) {
2423
if (array[i] === value) {
2524
return true;
2625
}
@@ -31,8 +30,7 @@ module ts {
3130

3231
export function indexOf<T>(array: T[], value: T): number {
3332
if (array) {
34-
var len = array.length;
35-
for (var i = 0; i < len; i++) {
33+
for (var i = 0, len = array.length; i < len; i++) {
3634
if (array[i] === value) {
3735
return i;
3836
}
@@ -42,9 +40,8 @@ module ts {
4240
}
4341

4442
export function filter<T>(array: T[], f: (x: T) => boolean): T[] {
45-
var result: T[];
4643
if (array) {
47-
result = [];
44+
var result: T[] = [];
4845
for (var i = 0, len = array.length; i < len; i++) {
4946
var item = array[i];
5047
if (f(item)) {
@@ -56,11 +53,9 @@ module ts {
5653
}
5754

5855
export function map<T, U>(array: T[], f: (x: T) => U): U[] {
59-
var result: U[];
6056
if (array) {
61-
result = [];
62-
var len = array.length;
63-
for (var i = 0; i < len; i++) {
57+
var result: U[] = [];
58+
for (var i = 0, len = array.length; i < len; i++) {
6459
result.push(f(array[i]));
6560
}
6661
}
@@ -73,6 +68,17 @@ module ts {
7368
return array1.concat(array2);
7469
}
7570

71+
export function uniqueElements<T>(array: T[]): T[] {
72+
if (array) {
73+
var result: T[] = [];
74+
for (var i = 0, len = array.length; i < len; i++) {
75+
var item = array[i];
76+
if (!contains(result, item)) result.push(item);
77+
}
78+
}
79+
return result;
80+
}
81+
7682
export function sum(array: any[], prop: string): number {
7783
var result = 0;
7884
for (var i = 0; i < array.length; i++) {
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‎tests/baselines/reference/tupleTypes.errors.txt‎

Copy file name to clipboardExpand all lines: tests/baselines/reference/tupleTypes.errors.txt
+3-3Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -16,8 +16,8 @@
1616

1717
t = []; // Error
1818
~
19-
!!! Type '[]' is not assignable to type '[number, string]':
20-
!!! Property '0' is missing in type '[]'.
19+
!!! Type '{}[]' is not assignable to type '[number, string]':
20+
!!! Property '0' is missing in type '{}[]'.
2121
t = [1]; // Error
2222
~
2323
!!! Type '[number]' is not assignable to type '[number, string]':
@@ -53,7 +53,7 @@
5353
tt = [undefined, undefined];
5454
tt = []; // Error
5555
~~
56-
!!! Type '[]' is not assignable to type '[number, string]'.
56+
!!! Type '{}[]' is not assignable to type '[number, string]'.
5757

5858
var a: number[];
5959
var a1: [number, string];

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