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Fixed nullish coalesce operator's precedence #61372

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Fixed nullish coalesce operator's precedence #61372

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6b77d0e
Fixed nullish coalesce operator's precedence
Andarist Mar 7, 2025
6f5d4a1
fmt
Andarist Mar 7, 2025
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25 changes: 15 additions & 10 deletions src/compiler/checker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -39843,18 +39843,23 @@ export function createTypeChecker(host: TypeCheckerHost): TypeChecker {
}

function checkNullishCoalesceOperands(node: BinaryExpression) {
const { left, operatorToken, right } = node;
if (operatorToken.kind === SyntaxKind.QuestionQuestionToken) {
if (isBinaryExpression(left) && (left.operatorToken.kind === SyntaxKind.BarBarToken || left.operatorToken.kind === SyntaxKind.AmpersandAmpersandToken)) {
grammarErrorOnNode(left, Diagnostics._0_and_1_operations_cannot_be_mixed_without_parentheses, tokenToString(left.operatorToken.kind), tokenToString(operatorToken.kind));
}
if (isBinaryExpression(right) && (right.operatorToken.kind === SyntaxKind.BarBarToken || right.operatorToken.kind === SyntaxKind.AmpersandAmpersandToken)) {
grammarErrorOnNode(right, Diagnostics._0_and_1_operations_cannot_be_mixed_without_parentheses, tokenToString(right.operatorToken.kind), tokenToString(operatorToken.kind));
if (node.operatorToken.kind !== SyntaxKind.QuestionQuestionToken) {
return;
}
if (isBinaryExpression(node.parent)) {
const { left, operatorToken } = node.parent;
if (isBinaryExpression(left) && (operatorToken.kind === SyntaxKind.BarBarToken || operatorToken.kind === SyntaxKind.AmpersandAmpersandToken)) {
grammarErrorOnNode(left, Diagnostics._0_and_1_operations_cannot_be_mixed_without_parentheses, tokenToString(SyntaxKind.QuestionQuestionToken), tokenToString(operatorToken.kind));
}

checkNullishCoalesceOperandLeft(node);
checkNullishCoalesceOperandRight(node);
}
else if (isBinaryExpression(node.left) && node.left.operatorToken.kind === SyntaxKind.BarBarToken) {
grammarErrorOnNode(node.left, Diagnostics._0_and_1_operations_cannot_be_mixed_without_parentheses, tokenToString(node.left.operatorToken.kind), tokenToString(SyntaxKind.QuestionQuestionToken));
}
else if (isBinaryExpression(node.right) && node.right.operatorToken.kind === SyntaxKind.AmpersandAmpersandToken) {
grammarErrorOnNode(node.right, Diagnostics._0_and_1_operations_cannot_be_mixed_without_parentheses, tokenToString(SyntaxKind.QuestionQuestionToken), tokenToString(node.right.operatorToken.kind));
}
checkNullishCoalesceOperandLeft(node);
checkNullishCoalesceOperandRight(node);
}

function checkNullishCoalesceOperandLeft(node: BinaryExpression) {
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12 changes: 6 additions & 6 deletions src/compiler/utilities.ts
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Expand Up @@ -5658,17 +5658,17 @@ export const enum OperatorPrecedence {
// CoalesceExpression
Conditional,

// LogicalORExpression:
// LogicalANDExpression
// LogicalORExpression `||` LogicalANDExpression
LogicalOR,

// CoalesceExpression:
// CoalesceExpressionHead `??` BitwiseORExpression
// CoalesceExpressionHead:
// CoalesceExpression
// BitwiseORExpression
Coalesce = Conditional, // NOTE: This is wrong
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I wonder how old this comment is...

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6 years, it was added in #35282


// LogicalORExpression:
// LogicalANDExpression
// LogicalORExpression `||` LogicalANDExpression
LogicalOR,
Coalesce = LogicalOR,

// LogicalANDExpression:
// BitwiseORExpression
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57 changes: 57 additions & 0 deletions src/testRunner/unittests/printer.ts
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Expand Up @@ -366,5 +366,62 @@ describe("unittests:: PrinterAPI", () => {
ts.factory.createNoSubstitutionTemplateLiteral("\n"),
ts.createSourceFile("source.ts", "", ts.ScriptTarget.ESNext),
));

printsCorrectly("binaryBarBarExpressionWithLeftConditionalExpression", {}, printer =>
printer.printNode(
ts.EmitHint.Unspecified,
ts.factory.createExpressionStatement(
ts.factory.createBinaryExpression(
ts.factory.createConditionalExpression(
ts.factory.createIdentifier("a"),
ts.factory.createToken(ts.SyntaxKind.QuestionToken),
ts.factory.createIdentifier("b"),
ts.factory.createToken(ts.SyntaxKind.ColonToken),
ts.factory.createIdentifier("c"),
),
ts.factory.createToken(ts.SyntaxKind.BarBarToken),
ts.factory.createIdentifier("d"),
),
),
ts.createSourceFile("source.ts", "", ts.ScriptTarget.ESNext),
));

printsCorrectly("binaryAmpersandAmpersandExpressionWithLeftConditionalExpression", {}, printer =>
printer.printNode(
ts.EmitHint.Unspecified,
ts.factory.createExpressionStatement(
ts.factory.createBinaryExpression(
ts.factory.createConditionalExpression(
ts.factory.createIdentifier("a"),
ts.factory.createToken(ts.SyntaxKind.QuestionToken),
ts.factory.createIdentifier("b"),
ts.factory.createToken(ts.SyntaxKind.ColonToken),
ts.factory.createIdentifier("c"),
),
ts.factory.createToken(ts.SyntaxKind.AmpersandAmpersandToken),
ts.factory.createIdentifier("d"),
),
),
ts.createSourceFile("source.ts", "", ts.ScriptTarget.ESNext),
));

printsCorrectly("binaryQuestionQuestionExpressionWithLeftConditionalExpression", {}, printer =>
printer.printNode(
ts.EmitHint.Unspecified,
ts.factory.createExpressionStatement(
ts.factory.createBinaryExpression(
ts.factory.createConditionalExpression(
ts.factory.createIdentifier("a"),
ts.factory.createToken(ts.SyntaxKind.QuestionToken),
ts.factory.createIdentifier("b"),
ts.factory.createToken(ts.SyntaxKind.ColonToken),
ts.factory.createIdentifier("c"),
),
ts.factory.createToken(ts.SyntaxKind.QuestionQuestionToken),
ts.factory.createIdentifier("d"),
),
),
ts.createSourceFile("source.ts", "", ts.ScriptTarget.ESNext),
));
});
});
15 changes: 6 additions & 9 deletions tests/baselines/reference/nullishCoalescingOperator5.errors.txt
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Original file line number Diff line number Diff line change
@@ -1,18 +1,17 @@
nullishCoalescingOperator5.ts(6,6): error TS5076: '||' and '??' operations cannot be mixed without parentheses.
nullishCoalescingOperator5.ts(6,1): error TS5076: '??' and '||' operations cannot be mixed without parentheses.
nullishCoalescingOperator5.ts(9,1): error TS5076: '||' and '??' operations cannot be mixed without parentheses.
nullishCoalescingOperator5.ts(12,6): error TS5076: '&&' and '??' operations cannot be mixed without parentheses.
nullishCoalescingOperator5.ts(15,1): error TS5076: '&&' and '??' operations cannot be mixed without parentheses.
nullishCoalescingOperator5.ts(12,6): error TS5076: '??' and '&&' operations cannot be mixed without parentheses.


==== nullishCoalescingOperator5.ts (4 errors) ====
==== nullishCoalescingOperator5.ts (3 errors) ====
declare const a: string | undefined
declare const b: string | undefined
declare const c: string | undefined

// should be a syntax error
a ?? b || c;
~~~~~~
!!! error TS5076: '||' and '??' operations cannot be mixed without parentheses.
~~~~~~
!!! error TS5076: '??' and '||' operations cannot be mixed without parentheses.

// should be a syntax error
a || b ?? c;
Expand All @@ -22,12 +21,10 @@ nullishCoalescingOperator5.ts(15,1): error TS5076: '&&' and '??' operations cann
// should be a syntax error
a ?? b && c;
~~~~~~
!!! error TS5076: '&&' and '??' operations cannot be mixed without parentheses.
!!! error TS5076: '??' and '&&' operations cannot be mixed without parentheses.

// should be a syntax error
a && b ?? c;
~~~~~~
!!! error TS5076: '&&' and '??' operations cannot be mixed without parentheses.

// Valid according to spec
a ?? (b || c);
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2 changes: 1 addition & 1 deletion tests/baselines/reference/nullishCoalescingOperator5.js
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Expand Up @@ -46,7 +46,7 @@ a && (b ?? c);
"use strict";
var _a, _b, _c, _d;
// should be a syntax error
a !== null && a !== void 0 ? a : b || c;
(a !== null && a !== void 0 ? a : b) || c;
// should be a syntax error
(_a = a || b) !== null && _a !== void 0 ? _a : c;
// should be a syntax error
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4 changes: 2 additions & 2 deletions tests/baselines/reference/nullishCoalescingOperator5.types
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Expand Up @@ -17,10 +17,10 @@ declare const c: string | undefined
a ?? b || c;
>a ?? b || c : string | undefined
> : ^^^^^^^^^^^^^^^^^^
>a ?? b : string | undefined
> : ^^^^^^^^^^^^^^^^^^
>a : string | undefined
> : ^^^^^^^^^^^^^^^^^^
>b || c : string | undefined
> : ^^^^^^^^^^^^^^^^^^
>b : string | undefined
> : ^^^^^^^^^^^^^^^^^^
>c : string | undefined
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6 changes: 3 additions & 3 deletions tests/baselines/reference/plainJSGrammarErrors.errors.txt
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Expand Up @@ -59,7 +59,7 @@ plainJSGrammarErrors.js(92,33): error TS2566: A rest element cannot have a prope
plainJSGrammarErrors.js(93,42): error TS1186: A rest element cannot have an initializer.
plainJSGrammarErrors.js(96,4): error TS1123: Variable declaration list cannot be empty.
plainJSGrammarErrors.js(97,9): error TS5076: '||' and '??' operations cannot be mixed without parentheses.
plainJSGrammarErrors.js(98,14): error TS5076: '||' and '??' operations cannot be mixed without parentheses.
plainJSGrammarErrors.js(98,9): error TS5076: '??' and '||' operations cannot be mixed without parentheses.
plainJSGrammarErrors.js(100,3): error TS1200: Line terminator not permitted before arrow.
plainJSGrammarErrors.js(102,4): error TS1358: Tagged template expressions are not permitted in an optional chain.
plainJSGrammarErrors.js(104,6): error TS1171: A comma expression is not allowed in a computed property name.
Expand Down Expand Up @@ -323,8 +323,8 @@ plainJSGrammarErrors.js(205,36): error TS1325: Argument of dynamic import cannot
~~~~~~
!!! error TS5076: '||' and '??' operations cannot be mixed without parentheses.
var x = 2 ?? 3 || 4
~~~~~~
!!! error TS5076: '||' and '??' operations cannot be mixed without parentheses.
~~~~~~
!!! error TS5076: '??' and '||' operations cannot be mixed without parentheses.
const arr = x
=> x + 1
~~
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4 changes: 2 additions & 2 deletions tests/baselines/reference/plainJSGrammarErrors.types
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Expand Up @@ -421,10 +421,10 @@ var x = 2 ?? 3 || 4
> : ^^^^^^
>2 ?? 3 || 4 : 2 | 3 | 4
> : ^^^^^^^^^
>2 ?? 3 : 2 | 3
> : ^^^^^
>2 : 2
> : ^
>3 || 4 : 3 | 4
> : ^^^^^
>3 : 3
> : ^
>4 : 4
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1 change: 1 addition & 0 deletions ...pi/printsNodeCorrectly.binaryAmpersandAmpersandExpressionWithLeftConditionalExpression.js
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@@ -0,0 +1 @@
(a ? b : c) && d;
1 change: 1 addition & 0 deletions ...nce/printerApi/printsNodeCorrectly.binaryBarBarExpressionWithLeftConditionalExpression.js
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@@ -0,0 +1 @@
(a ? b : c) || d;
1 change: 1 addition & 0 deletions ...rApi/printsNodeCorrectly.binaryQuestionQuestionExpressionWithLeftConditionalExpression.js
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@@ -0,0 +1 @@
(a ? b : c) ?? d;