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Instantiate inferred type parameter constraints

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This commit is contained in:
Anders Hejlsberg
2018-02-06 17:21:18 -08:00
parent af8150363b
commit e62abbb9f8
1 changed files with 16 additions and 14 deletions
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src/compiler/checker.ts
+16 -14
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@@ -6977,7 +6977,11 @@ namespace ts {
if (typeParameters) {
const index = typeReference.typeArguments.indexOf(<TypeNode>declaration.parent);
if (index < typeParameters.length) {
constraints = append(constraints, getBaseConstraintOfType(typeParameters[index]));
const constraint = getConstraintOfTypeParameter(typeParameters[index]);
if (constraint) {
const mapper = createTypeMapper(typeParameters, getEffectiveTypeArguments(typeReference, typeParameters));
constraints = append(constraints, instantiateType(constraint, mapper));
}
}
}
}
@@ -20192,8 +20196,12 @@ namespace ts {
checkDecorators(node);
}
function checkTypeArgumentConstraints(typeParameters: TypeParameter[], typeArgumentNodes: ReadonlyArray<TypeNode>): boolean {
function getEffectiveTypeArguments(node: TypeReferenceNode | ExpressionWithTypeArguments, typeParameters: TypeParameter[]) {
const minTypeArgumentCount = getMinTypeArgumentCount(typeParameters);
return fillMissingTypeArguments(map(node.typeArguments, getTypeFromTypeNode), typeParameters, minTypeArgumentCount, isInJavaScriptFile(node));
}
function checkTypeArgumentConstraints(node: TypeReferenceNode | ExpressionWithTypeArguments, typeParameters: TypeParameter[]): boolean {
let typeArguments: Type[];
let mapper: TypeMapper;
let result = true;
@@ -20201,14 +20209,14 @@ namespace ts {
const constraint = getConstraintOfTypeParameter(typeParameters[i]);
if (constraint) {
if (!typeArguments) {
typeArguments = fillMissingTypeArguments(map(typeArgumentNodes, getTypeFromTypeNode), typeParameters, minTypeArgumentCount, isInJavaScriptFile(typeArgumentNodes[i]));
typeArguments = getEffectiveTypeArguments(node, typeParameters);
mapper = createTypeMapper(typeParameters, typeArguments);
}
const typeArgument = typeArguments[i];
result = result && checkTypeAssignableTo(
typeArgument,
instantiateType(constraint, mapper),
typeArgumentNodes[i],
node.typeArguments[i],
Diagnostics.Type_0_does_not_satisfy_the_constraint_1);
}
}
@@ -20220,13 +20228,8 @@ namespace ts {
if (type !== unknownType) {
const symbol = getNodeLinks(node).resolvedSymbol;
if (symbol) {
const typeAliasParameters = symbol.flags & SymbolFlags.TypeAlias && getSymbolLinks(symbol).typeParameters;
if (typeAliasParameters) {
return typeAliasParameters;
}
if (getObjectFlags(type) & ObjectFlags.Reference) {
return (<TypeReference>type).target.localTypeParameters;
}
return symbol.flags & SymbolFlags.TypeAlias && getSymbolLinks(symbol).typeParameters ||
(getObjectFlags(type) & ObjectFlags.Reference ? (<TypeReference>type).target.localTypeParameters : undefined);
}
}
return undefined;
@@ -20236,7 +20239,6 @@ namespace ts {
checkGrammarTypeArguments(node, node.typeArguments);
if (node.kind === SyntaxKind.TypeReference && node.typeName.jsdocDotPos !== undefined && !isInJavaScriptFile(node) && !isInJSDoc(node)) {
grammarErrorAtPos(node, node.typeName.jsdocDotPos, 1, Diagnostics.JSDoc_types_can_only_be_used_inside_documentation_comments);
}
const type = getTypeFromTypeReference(node);
if (type !== unknownType) {
@@ -20246,7 +20248,7 @@ namespace ts {
if (produceDiagnostics) {
const typeParameters = getTypeParametersForTypeReference(node);
if (typeParameters) {
checkTypeArgumentConstraints(typeParameters, node.typeArguments);
checkTypeArgumentConstraints(node, typeParameters);
}
}
}
@@ -22944,7 +22946,7 @@ namespace ts {
if (some(baseTypeNode.typeArguments)) {
forEach(baseTypeNode.typeArguments, checkSourceElement);
for (const constructor of getConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments, baseTypeNode)) {
if (!checkTypeArgumentConstraints(constructor.typeParameters, baseTypeNode.typeArguments)) {
if (!checkTypeArgumentConstraints(baseTypeNode, constructor.typeParameters)) {
break;
}
}