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Use {} type facts for unconstrained type params

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Previously it was using TypeFacts.All. But the constraint of an
unconstrained type parameter is actually {}.
This commit is contained in:
Nathan Shively-Sanders
2016-08-03 14:36:05 -07:00
parent 4189b4d718
commit 045b51a8ef
2 changed files with 10 additions and 25 deletions
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33
src/compiler/checker.ts
View File

@@ -1187,7 +1187,7 @@ namespace ts {
}
function resolveSymbol(symbol: Symbol): Symbol {
return symbol && symbol.flags & SymbolFlags.Alias && !(symbol.flags & (SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace)) ? resolveAlias(symbol) : symbol;
return symbol && symbol.flags & SymbolFlags.Alias && !(symbol.flags & (SymbolFlags.Value | SymbolFlags.Type | SymbolFlags.Namespace)) ? resolveAlias(symbol) : symbol;
}
function resolveAlias(symbol: Symbol): Symbol {
@@ -7892,7 +7892,7 @@ namespace ts {
}
if (flags & TypeFlags.TypeParameter) {
const constraint = getConstraintOfTypeParameter(<TypeParameter>type);
return constraint ? getTypeFacts(constraint) : TypeFacts.All;
return getTypeFacts(constraint || emptyObjectType);
}
if (flags & TypeFlags.UnionOrIntersection) {
return getTypeFactsOfTypes((<UnionOrIntersectionType>type).types);
@@ -7900,17 +7900,13 @@ namespace ts {
return TypeFacts.All;
}
function getTypeWithFacts(type: Type, include: TypeFacts, intersectForTypeParameters = false) {
function getTypeWithFacts(type: Type, include: TypeFacts) {
if (!(type.flags & TypeFlags.Union)) {
return getTypeFacts(type) & include ? type : neverType;
}
let firstType: Type;
let hasTypeParameter = false;
let types: Type[];
for (const t of (type as UnionType).types) {
if (t.flags & TypeFlags.TypeParameter) {
hasTypeParameter = true;
}
if (getTypeFacts(t) & include) {
if (!firstType) {
firstType = t;
@@ -7923,19 +7919,8 @@ namespace ts {
}
}
}
const narrowed = types ? getUnionType(types) :
firstType ? firstType : neverType;
// if there is a type parameter in the narrowed type,
// add an intersection with the members of the narrowed type so that the shape of the type is correct
if (type.flags & TypeFlags.Union &&
narrowed.flags & TypeFlags.Union &&
hasTypeParameter &&
intersectForTypeParameters) {
return getIntersectionType(types.concat([narrowed]));
}
else {
return narrowed;
}
return types ? getUnionType(types) :
firstType ? firstType : neverType;
}
function getTypeWithDefault(type: Type, defaultExpression: Expression) {
@@ -8308,10 +8293,10 @@ namespace ts {
function narrowTypeByTruthiness(type: Type, expr: Expression, assumeTrue: boolean): Type {
if (isMatchingReference(reference, expr)) {
return getTypeWithFacts(type, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy, assumeTrue);
return getTypeWithFacts(type, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy);
}
if (isMatchingPropertyAccess(expr)) {
return narrowTypeByDiscriminant(type, <PropertyAccessExpression>expr, t => getTypeWithFacts(t, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy, assumeTrue));
return narrowTypeByDiscriminant(type, <PropertyAccessExpression>expr, t => getTypeWithFacts(t, assumeTrue ? TypeFacts.Truthy : TypeFacts.Falsy));
}
return type;
}
@@ -8369,7 +8354,7 @@ namespace ts {
value.kind === SyntaxKind.NullKeyword ?
assumeTrue ? TypeFacts.EQNull : TypeFacts.NENull :
assumeTrue ? TypeFacts.EQUndefined : TypeFacts.NEUndefined;
return getTypeWithFacts(type, facts, assumeTrue);
return getTypeWithFacts(type, facts);
}
if (type.flags & TypeFlags.NotUnionOrUnit) {
return type;
@@ -8407,7 +8392,7 @@ namespace ts {
const facts = assumeTrue ?
getProperty(typeofEQFacts, literal.text) || TypeFacts.TypeofEQHostObject :
getProperty(typeofNEFacts, literal.text) || TypeFacts.TypeofNEHostObject;
return getTypeWithFacts(type, facts, assumeTrue);
return getTypeWithFacts(type, facts);
}
function narrowTypeBySwitchOnDiscriminant(type: Type, switchStatement: SwitchStatement, clauseStart: number, clauseEnd: number) {

2
tests/baselines/reference/controlFlowIfStatement.types
View File

@@ -108,7 +108,7 @@ function c<T>(data: string | T): T {
>JSON.parse : (text: string, reviver?: (key: any, value: any) => any) => any
>JSON : JSON
>parse : (text: string, reviver?: (key: any, value: any) => any) => any
>data : string & T & (string | T)
>data : string
}
else {
return data;