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Merge pull request #10069 from Microsoft/bestChoiceType

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Use "best choice type" for || and ?: operators
This commit is contained in:
Anders Hejlsberg 2016-08-01 15:26:57 -07:00 committed by GitHub
commit 1435fb19a8
9 changed files with 223 additions and 10 deletions
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12
src/compiler/checker.ts
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@ -12903,6 +12903,14 @@ namespace ts {
return (target.flags & TypeFlags.Nullable) !== 0 || isTypeComparableTo(source, target);
}
function getBestChoiceType(type1: Type, type2: Type): Type {
const firstAssignableToSecond = isTypeAssignableTo(type1, type2);
const secondAssignableToFirst = isTypeAssignableTo(type2, type1);
return secondAssignableToFirst && !firstAssignableToSecond ? type1 :
firstAssignableToSecond && !secondAssignableToFirst ? type2 :
getUnionType([type1, type2], /*subtypeReduction*/ true);
}
function checkBinaryExpression(node: BinaryExpression, contextualMapper?: TypeMapper) {
return checkBinaryLikeExpression(node.left, node.operatorToken, node.right, contextualMapper, node);
}
@ -13046,7 +13054,7 @@ namespace ts {
leftType;
case SyntaxKind.BarBarToken:
return getTypeFacts(leftType) & TypeFacts.Falsy ?
getUnionType([removeDefinitelyFalsyTypes(leftType), rightType], /*subtypeReduction*/ true) :
getBestChoiceType(removeDefinitelyFalsyTypes(leftType), rightType) :
leftType;
case SyntaxKind.EqualsToken:
checkAssignmentOperator(rightType);
@ -13173,7 +13181,7 @@ namespace ts {
checkExpression(node.condition);
const type1 = checkExpression(node.whenTrue, contextualMapper);
const type2 = checkExpression(node.whenFalse, contextualMapper);
return getUnionType([type1, type2], /*subtypeReduction*/ true);
return getBestChoiceType(type1, type2);
}
function typeContainsLiteralFromEnum(type: Type, enumType: EnumType) {

35
tests/baselines/reference/bestChoiceType.js Normal file
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@ -0,0 +1,35 @@
//// [bestChoiceType.ts]
// Repro from #10041
(''.match(/ /) || []).map(s => s.toLowerCase());
// Similar cases
function f1() {
let x = ''.match(/ /);
let y = x || [];
let z = y.map(s => s.toLowerCase());
}
function f2() {
let x = ''.match(/ /);
let y = x ? x : [];
let z = y.map(s => s.toLowerCase());
}
//// [bestChoiceType.js]
// Repro from #10041
(''.match(/ /) || []).map(function (s) { return s.toLowerCase(); });
// Similar cases
function f1() {
var x = ''.match(/ /);
var y = x || [];
var z = y.map(function (s) { return s.toLowerCase(); });
}
function f2() {
var x = ''.match(/ /);
var y = x ? x : [];
var z = y.map(function (s) { return s.toLowerCase(); });
}

63
tests/baselines/reference/bestChoiceType.symbols Normal file
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@ -0,0 +1,63 @@
=== tests/cases/compiler/bestChoiceType.ts ===
// Repro from #10041
(''.match(/ /) || []).map(s => s.toLowerCase());
>(''.match(/ /) || []).map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>''.match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
>match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
>map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 3, 26))
>s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 3, 26))
>toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
// Similar cases
function f1() {
>f1 : Symbol(f1, Decl(bestChoiceType.ts, 3, 48))
let x = ''.match(/ /);
>x : Symbol(x, Decl(bestChoiceType.ts, 8, 7))
>''.match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
>match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
let y = x || [];
>y : Symbol(y, Decl(bestChoiceType.ts, 9, 7))
>x : Symbol(x, Decl(bestChoiceType.ts, 8, 7))
let z = y.map(s => s.toLowerCase());
>z : Symbol(z, Decl(bestChoiceType.ts, 10, 7))
>y.map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>y : Symbol(y, Decl(bestChoiceType.ts, 9, 7))
>map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 10, 18))
>s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 10, 18))
>toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
}
function f2() {
>f2 : Symbol(f2, Decl(bestChoiceType.ts, 11, 1))
let x = ''.match(/ /);
>x : Symbol(x, Decl(bestChoiceType.ts, 14, 7))
>''.match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
>match : Symbol(String.match, Decl(lib.d.ts, --, --), Decl(lib.d.ts, --, --))
let y = x ? x : [];
>y : Symbol(y, Decl(bestChoiceType.ts, 15, 7))
>x : Symbol(x, Decl(bestChoiceType.ts, 14, 7))
>x : Symbol(x, Decl(bestChoiceType.ts, 14, 7))
let z = y.map(s => s.toLowerCase());
>z : Symbol(z, Decl(bestChoiceType.ts, 16, 7))
>y.map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>y : Symbol(y, Decl(bestChoiceType.ts, 15, 7))
>map : Symbol(Array.map, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 16, 18))
>s.toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
>s : Symbol(s, Decl(bestChoiceType.ts, 16, 18))
>toLowerCase : Symbol(String.toLowerCase, Decl(lib.d.ts, --, --))
}

88
tests/baselines/reference/bestChoiceType.types Normal file
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@ -0,0 +1,88 @@
=== tests/cases/compiler/bestChoiceType.ts ===
// Repro from #10041
(''.match(/ /) || []).map(s => s.toLowerCase());
>(''.match(/ /) || []).map(s => s.toLowerCase()) : string[]
>(''.match(/ /) || []).map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>(''.match(/ /) || []) : RegExpMatchArray
>''.match(/ /) || [] : RegExpMatchArray
>''.match(/ /) : RegExpMatchArray | null
>''.match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>'' : string
>match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>/ / : RegExp
>[] : never[]
>map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>s => s.toLowerCase() : (s: string) => string
>s : string
>s.toLowerCase() : string
>s.toLowerCase : () => string
>s : string
>toLowerCase : () => string
// Similar cases
function f1() {
>f1 : () => void
let x = ''.match(/ /);
>x : RegExpMatchArray | null
>''.match(/ /) : RegExpMatchArray | null
>''.match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>'' : string
>match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>/ / : RegExp
let y = x || [];
>y : RegExpMatchArray
>x || [] : RegExpMatchArray
>x : RegExpMatchArray | null
>[] : never[]
let z = y.map(s => s.toLowerCase());
>z : string[]
>y.map(s => s.toLowerCase()) : string[]
>y.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>y : RegExpMatchArray
>map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>s => s.toLowerCase() : (s: string) => string
>s : string
>s.toLowerCase() : string
>s.toLowerCase : () => string
>s : string
>toLowerCase : () => string
}
function f2() {
>f2 : () => void
let x = ''.match(/ /);
>x : RegExpMatchArray | null
>''.match(/ /) : RegExpMatchArray | null
>''.match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>'' : string
>match : { (regexp: string): RegExpMatchArray | null; (regexp: RegExp): RegExpMatchArray | null; }
>/ / : RegExp
let y = x ? x : [];
>y : RegExpMatchArray
>x ? x : [] : RegExpMatchArray
>x : RegExpMatchArray | null
>x : RegExpMatchArray
>[] : never[]
let z = y.map(s => s.toLowerCase());
>z : string[]
>y.map(s => s.toLowerCase()) : string[]
>y.map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>y : RegExpMatchArray
>map : <U>(callbackfn: (value: string, index: number, array: string[]) => U, thisArg?: any) => U[]
>s => s.toLowerCase() : (s: string) => string
>s : string
>s.toLowerCase() : string
>s.toLowerCase : () => string
>s : string
>toLowerCase : () => string
}

4
tests/baselines/reference/nonContextuallyTypedLogicalOr.symbols
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@ -28,8 +28,8 @@ var e: Ellement;
>Ellement : Symbol(Ellement, Decl(nonContextuallyTypedLogicalOr.ts, 3, 1))
(c || e).dummy;
>(c || e).dummy : Symbol(dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22), Decl(nonContextuallyTypedLogicalOr.ts, 5, 20))
>(c || e).dummy : Symbol(Contextual.dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22))
>c : Symbol(c, Decl(nonContextuallyTypedLogicalOr.ts, 10, 3))
>e : Symbol(e, Decl(nonContextuallyTypedLogicalOr.ts, 11, 3))
>dummy : Symbol(dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22), Decl(nonContextuallyTypedLogicalOr.ts, 5, 20))
>dummy : Symbol(Contextual.dummy, Decl(nonContextuallyTypedLogicalOr.ts, 0, 22))

4
tests/baselines/reference/nonContextuallyTypedLogicalOr.types
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@ -29,8 +29,8 @@ var e: Ellement;
(c || e).dummy;
>(c || e).dummy : any
>(c || e) : Contextual | Ellement
>c || e : Contextual | Ellement
>(c || e) : Contextual
>c || e : Contextual
>c : Contextual
>e : Ellement
>dummy : any

4
tests/baselines/reference/subtypingWithObjectMembersOptionality3.types
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@ -69,8 +69,8 @@ var b: { Foo2: Derived; }
>Derived : Derived
var r = true ? a : b; // ok
>r : { Foo?: Base; } | { Foo2: Derived; }
>true ? a : b : { Foo?: Base; } | { Foo2: Derived; }
>r : { Foo?: Base; }
>true ? a : b : { Foo?: Base; }
>true : boolean
>a : { Foo?: Base; }
>b : { Foo2: Derived; }

4
tests/baselines/reference/subtypingWithObjectMembersOptionality4.types
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@ -69,8 +69,8 @@ var b: { Foo2?: Derived; }
>Derived : Derived
var r = true ? a : b; // ok
>r : { Foo: Base; } | { Foo2?: Derived; }
>true ? a : b : { Foo: Base; } | { Foo2?: Derived; }
>r : { Foo2?: Derived; }
>true ? a : b : { Foo2?: Derived; }
>true : boolean
>a : { Foo: Base; }
>b : { Foo2?: Derived; }

19
tests/cases/compiler/bestChoiceType.ts Normal file
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@ -0,0 +1,19 @@
// @strictNullChecks: true
// Repro from #10041
(''.match(/ /) || []).map(s => s.toLowerCase());
// Similar cases
function f1() {
let x = ''.match(/ /);
let y = x || [];
let z = y.map(s => s.toLowerCase());
}
function f2() {
let x = ''.match(/ /);
let y = x ? x : [];
let z = y.map(s => s.toLowerCase());
}