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Include readonly in type equality checks + Treat more symbols as readonly

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This commit is contained in:
Anders Hejlsberg 2016-01-24 13:44:05 -08:00
parent 7405a4b9c8
commit 49dd54e91a
1 changed files with 17 additions and 9 deletions
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26
src/compiler/checker.ts
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@ -134,7 +134,7 @@ namespace ts {
const anySignature = createSignature(undefined, undefined, emptyArray, anyType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const unknownSignature = createSignature(undefined, undefined, emptyArray, unknownType, 0, /*hasRestParameter*/ false, /*hasStringLiterals*/ false);
const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ false);
const enumNumberIndexInfo = createIndexInfo(stringType, /*isReadonly*/ true);
const globals: SymbolTable = {};
@ -5912,6 +5912,9 @@ namespace ts {
return Ternary.False;
}
}
if (isReadonlySymbol(sourceProp) !== isReadonlySymbol(targetProp)) {
return Ternary.False;
}
return compareTypes(getTypeOfSymbol(sourceProp), getTypeOfSymbol(targetProp));
}
@ -10380,15 +10383,18 @@ namespace ts {
}
function isReadonlySymbol(symbol: Symbol): boolean {
// The following symbols are considered read-only:
// Properties with a 'readonly' modifier
// Variables declared with 'const'
// Get accessors without matching set accessors
// Enum members
return symbol.flags & SymbolFlags.Property && (getDeclarationFlagsFromSymbol(symbol) & NodeFlags.Readonly) !== 0 ||
symbol.flags & SymbolFlags.Accessor && !(symbol.flags & SymbolFlags.SetAccessor);
symbol.flags & SymbolFlags.Variable && (getDeclarationFlagsFromSymbol(symbol) & NodeFlags.Const) !== 0 ||
symbol.flags & SymbolFlags.Accessor && !(symbol.flags & SymbolFlags.SetAccessor) ||
(symbol.flags & SymbolFlags.EnumMember) !== 0;
}
function isConstantSymbol(symbol: Symbol): boolean {
return symbol.flags & SymbolFlags.Variable && (getDeclarationFlagsFromSymbol(symbol) & NodeFlags.Const) !== 0;
}
function isReferenceToReadonlyProperty(expr: Expression, symbol: Symbol): boolean {
function isReferenceToReadonlyEntity(expr: Expression, symbol: Symbol): boolean {
if (isReadonlySymbol(symbol)) {
// Allow assignments to readonly properties within constructors of the same class declaration.
if (symbol.flags & SymbolFlags.Property &&
@ -10430,11 +10436,13 @@ namespace ts {
const symbol = getExportSymbolOfValueSymbolIfExported(links.resolvedSymbol);
if (symbol) {
if (symbol !== unknownSymbol && symbol !== argumentsSymbol) {
if (node.kind === SyntaxKind.Identifier && !(symbol.flags & SymbolFlags.Variable) || symbol.flags & SymbolFlags.EnumMember) {
// Only variables (and not functions, classes, namespaces, enum objects, or enum members)
// are considered references when referenced using a simple identifier.
if (node.kind === SyntaxKind.Identifier && !(symbol.flags & SymbolFlags.Variable)) {
error(expr, invalidReferenceMessage);
return false;
}
if (isConstantSymbol(symbol) || isReferenceToReadonlyProperty(node, symbol) || isReferenceThroughNamespaceImport(node)) {
if (isReferenceToReadonlyEntity(node, symbol) || isReferenceThroughNamespaceImport(node)) {
error(expr, constantVariableMessage);
return false;
}