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Merge pull request #19056 from Microsoft/fix16221

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Fix recursive reference in type parameter default
This commit is contained in:
Ron Buckton
2017-10-11 12:49:35 -07:00
committed by GitHub
parent bce77fdfd9 26290a88ac
commit 73d06f796d
11 changed files with 98 additions and 22 deletions
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60
src/compiler/checker.ts
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@@ -281,6 +281,7 @@ namespace ts {
const noConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const circularConstraintType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const resolvingDefaultType = createAnonymousType(undefined, emptySymbols, emptyArray, emptyArray, undefined, undefined);
const markerSuperType = <TypeParameter>createType(TypeFlags.TypeParameter);
const markerSubType = <TypeParameter>createType(TypeFlags.TypeParameter);
@@ -6055,27 +6056,51 @@ namespace ts {
return type.resolvedApparentType || (type.resolvedApparentType = getTypeWithThisArgument(type, type));
}
function getResolvedTypeParameterDefault(typeParameter: TypeParameter): Type | undefined {
if (!typeParameter.default) {
if (typeParameter.target) {
const targetDefault = getResolvedTypeParameterDefault(typeParameter.target);
typeParameter.default = targetDefault ? instantiateType(targetDefault, typeParameter.mapper) : noConstraintType;
}
else {
// To block recursion, set the initial value to the resolvingDefaultType.
typeParameter.default = resolvingDefaultType;
const defaultDeclaration = typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameterDeclaration(decl) && decl.default);
const defaultType = defaultDeclaration ? getTypeFromTypeNode(defaultDeclaration) : noConstraintType;
if (typeParameter.default === resolvingDefaultType) {
// If we have not been called recursively, set the correct default type.
typeParameter.default = defaultType;
}
}
}
else if (typeParameter.default === resolvingDefaultType) {
// If we are called recursively for this type parameter, mark the default as circular.
typeParameter.default = circularConstraintType;
}
return typeParameter.default;
}
/**
* Gets the default type for a type parameter.
*
* If the type parameter is the result of an instantiation, this gets the instantiated
* default type of its target. If the type parameter has no default type, `undefined`
* is returned.
*
* This function *does not* perform a circularity check.
* default type of its target. If the type parameter has no default type or the default is
* circular, `undefined` is returned.
*/
function getDefaultFromTypeParameter(typeParameter: TypeParameter): Type | undefined {
if (!typeParameter.default) {
if (typeParameter.target) {
const targetDefault = getDefaultFromTypeParameter(typeParameter.target);
typeParameter.default = targetDefault ? instantiateType(targetDefault, typeParameter.mapper) : noConstraintType;
}
else {
const defaultDeclaration = typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameterDeclaration(decl) && decl.default);
typeParameter.default = defaultDeclaration ? getTypeFromTypeNode(defaultDeclaration) : noConstraintType;
}
}
return typeParameter.default === noConstraintType ? undefined : typeParameter.default;
const defaultType = getResolvedTypeParameterDefault(typeParameter);
return defaultType !== noConstraintType && defaultType !== circularConstraintType ? defaultType : undefined;
}
function hasNonCircularTypeParameterDefault(typeParameter: TypeParameter) {
return getResolvedTypeParameterDefault(typeParameter) !== circularConstraintType;
}
/**
* Indicates whether the declaration of a typeParameter has a default type.
*/
function hasTypeParameterDefault(typeParameter: TypeParameter): boolean {
return !!(typeParameter.symbol && forEach(typeParameter.symbol.declarations, decl => isTypeParameterDeclaration(decl) && decl.default));
}
/**
@@ -6361,7 +6386,7 @@ namespace ts {
let minTypeArgumentCount = 0;
if (typeParameters) {
for (let i = 0; i < typeParameters.length; i++) {
if (!getDefaultFromTypeParameter(typeParameters[i])) {
if (!hasTypeParameterDefault(typeParameters[i])) {
minTypeArgumentCount = i + 1;
}
}
@@ -18478,6 +18503,9 @@ namespace ts {
if (!hasNonCircularBaseConstraint(typeParameter)) {
error(node.constraint, Diagnostics.Type_parameter_0_has_a_circular_constraint, typeToString(typeParameter));
}
if (!hasNonCircularTypeParameterDefault(typeParameter)) {
error(node.default, Diagnostics.Type_parameter_0_has_a_circular_default, typeToString(typeParameter));
}
const constraintType = getConstraintOfTypeParameter(typeParameter);
const defaultType = getDefaultFromTypeParameter(typeParameter);
if (constraintType && defaultType) {

4
src/compiler/diagnosticMessages.json
View File

@@ -2224,6 +2224,10 @@
"category": "Error",
"code": 2715
},
"Type parameter '{0}' has a circular default.": {
"category": "Error",
"code": 2716
},
"Import declaration '{0}' is using private name '{1}'.": {
"category": "Error",