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Narrow by comparisons to boolean literals (#53714)

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This commit is contained in:
Mateusz Burzyński
2023-09-19 13:38:31 -07:00
committed by GitHub
parent 7d9399e353
commit 1f88596bb1
5 changed files with 701 additions and 1 deletions
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src/compiler/binder.ts
+3 -1
View File
@@ -136,6 +136,7 @@ import {
isBlock,
isBlockOrCatchScoped,
IsBlockScopedContainer,
isBooleanLiteral,
isCallExpression,
isClassStaticBlockDeclaration,
isConditionalTypeNode,
@@ -1279,7 +1280,8 @@ function createBinder(): (file: SourceFile, options: CompilerOptions) => void {
case SyntaxKind.EqualsEqualsEqualsToken:
case SyntaxKind.ExclamationEqualsEqualsToken:
return isNarrowableOperand(expr.left) || isNarrowableOperand(expr.right) ||
isNarrowingTypeofOperands(expr.right, expr.left) || isNarrowingTypeofOperands(expr.left, expr.right);
isNarrowingTypeofOperands(expr.right, expr.left) || isNarrowingTypeofOperands(expr.left, expr.right) ||
(isBooleanLiteral(expr.right) && isNarrowingExpression(expr.left) || isBooleanLiteral(expr.left) && isNarrowingExpression(expr.right));
case SyntaxKind.InstanceOfKeyword:
return isNarrowableOperand(expr.left);
case SyntaxKind.InKeyword:
src/compiler/checker.ts
+13
View File
@@ -34,6 +34,7 @@ import {
BigIntLiteral,
BigIntLiteralType,
BinaryExpression,
BinaryOperator,
BinaryOperatorToken,
binarySearch,
BindableObjectDefinePropertyCall,
@@ -44,6 +45,7 @@ import {
BindingPattern,
bindSourceFile,
Block,
BooleanLiteral,
BreakOrContinueStatement,
CallChain,
CallExpression,
@@ -27661,6 +27663,11 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
return type;
}
function narrowTypeByBooleanComparison(type: Type, expr: Expression, bool: BooleanLiteral, operator: BinaryOperator, assumeTrue: boolean): Type {
assumeTrue = (assumeTrue !== (bool.kind === SyntaxKind.TrueKeyword)) !== (operator !== SyntaxKind.ExclamationEqualsEqualsToken && operator !== SyntaxKind.ExclamationEqualsToken);
return narrowType(type, expr, assumeTrue);
}
function narrowTypeByBinaryExpression(type: Type, expr: BinaryExpression, assumeTrue: boolean): Type {
switch (expr.operatorToken.kind) {
case SyntaxKind.EqualsToken:
@@ -27709,6 +27716,12 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
if (isMatchingConstructorReference(right)) {
return narrowTypeByConstructor(type, operator, left, assumeTrue);
}
if (isBooleanLiteral(right)) {
return narrowTypeByBooleanComparison(type, left, right, operator, assumeTrue);
}
if (isBooleanLiteral(left)) {
return narrowTypeByBooleanComparison(type, right, left, operator, assumeTrue);
}
break;
case SyntaxKind.InstanceOfKeyword:
return narrowTypeByInstanceof(type, expr, assumeTrue);