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Fixed a crash on JSX emit trying to emit unexpectedly recovered BinaryExpression in a JSX attribute #64470

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Fixed a crash on JSX emit trying to emit unexpectedly recovered BinaryExpression in a JSX attribute #64470

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3f88816
Add failing test for JSX attribute initializer with multiple elements…
Andarist Sep 26, 2026
66c38a0
Don't wrap JSX attribute values in synthetic sibling-element binary e…
Andarist Sep 26, 2026
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4 changes: 3 additions & 1 deletion tsc/internal/parser/parser.go
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Expand Up @@ -5093,7 +5093,9 @@ func (p *Parser) parseJsxAttributeValue() *ast.Expression {
return p.parseJsxExpression( /*inExpressionContext*/ true)
}
if p.token == ast.KindLessThanToken {
return p.parseJsxElementOrSelfClosingElementOrFragment(true /*inExpressionContext*/, -1, nil, false)
// An attribute value must be a single JsxAttributeValue, so don't allow the sibling-element
// recovery to wrap it in a synthetic binary expression.
return p.parseJsxElementOrSelfClosingElementOrFragment(true /*inExpressionContext*/, -1 /*topInvalidNodePosition*/, nil /*openingTag*/, true /*mustBeUnary*/)

@Andarist Mateusz Burzyński (Andarist) Sep 26, 2026

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I think it's best to handle this here - where the bad data was created. All of the other code just doesn't expect BinaryExpression here given:

type JsxAttributeValue = StringLiteral | JsxExpression | JsxElement | JsxSelfClosingElement | JsxFragment

}
p.parseErrorAtCurrentToken(diagnostics.X_or_JSX_element_expected)
}
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20 changes: 20 additions & 0 deletions ...s/reference/compiler/jsxAttributeInitializerMultipleElementsNoCrash(jsx=react).errors.txt
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@@ -0,0 +1,20 @@
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,11): error TS2657: JSX expressions must have one parent element.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,29): error TS1003: Identifier expected.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,39): error TS1109: Expression expected.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,40): error TS1109: Expression expected.


==== jsxAttributeInitializerMultipleElementsNoCrash.tsx (4 errors) ====
declare namespace JSX { interface IntrinsicElements { [x: string]: any } }
declare const React: any;

const a = <div attr=<span /><span /> />;
~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2657: JSX expressions must have one parent element.
~
!!! error TS1003: Identifier expected.
~
!!! error TS1109: Expression expected.
~
!!! error TS1109: Expression expected.

12 changes: 12 additions & 0 deletions ...baselines/reference/compiler/jsxAttributeInitializerMultipleElementsNoCrash(jsx=react).js
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@@ -0,0 +1,12 @@
//// [tests/cases/compiler/jsxAttributeInitializerMultipleElementsNoCrash.tsx] ////

//// [jsxAttributeInitializerMultipleElementsNoCrash.tsx]
declare namespace JSX { interface IntrinsicElements { [x: string]: any } }
declare const React: any;

const a = <div attr=<span /><span /> />;


//// [jsxAttributeInitializerMultipleElementsNoCrash.js]
"use strict";
const a = (React.createElement("div", { attr: React.createElement("span", null) }), React.createElement("span", null)) / > ;
32 changes: 32 additions & 0 deletions ...ference/compiler/jsxAttributeInitializerMultipleElementsNoCrash(jsx=react-jsx).errors.txt
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@@ -0,0 +1,32 @@
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,11): error TS2875: This JSX tag requires the module path 'react/jsx-runtime' to exist, but none could be found. Make sure you have types for the appropriate package installed.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,11): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,11): error TS2657: JSX expressions must have one parent element.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,21): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,29): error TS1003: Identifier expected.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,29): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,39): error TS1109: Expression expected.
jsxAttributeInitializerMultipleElementsNoCrash.tsx(4,40): error TS1109: Expression expected.


==== jsxAttributeInitializerMultipleElementsNoCrash.tsx (8 errors) ====
declare namespace JSX { interface IntrinsicElements { [x: string]: any } }
declare const React: any;

const a = <div attr=<span /><span /> />;
~~~~~~~~~~~~~~~~~~
!!! error TS2875: This JSX tag requires the module path 'react/jsx-runtime' to exist, but none could be found. Make sure you have types for the appropriate package installed.
~~~~~~~~~~~~~~~~~~
!!! error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
~~~~~~~~~~~~~~~~~~~~~~~~~~
!!! error TS2657: JSX expressions must have one parent element.
~~~~~~~~
!!! error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
~
!!! error TS1003: Identifier expected.
~~~~~~~~
!!! error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
~
!!! error TS1109: Expression expected.
~
!!! error TS1109: Expression expected.

12 changes: 12 additions & 0 deletions ...lines/reference/compiler/jsxAttributeInitializerMultipleElementsNoCrash(jsx=react-jsx).js
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@@ -0,0 +1,12 @@
//// [tests/cases/compiler/jsxAttributeInitializerMultipleElementsNoCrash.tsx] ////

//// [jsxAttributeInitializerMultipleElementsNoCrash.tsx]
declare namespace JSX { interface IntrinsicElements { [x: string]: any } }
declare const React: any;

const a = <div attr=<span /><span /> />;


//// [jsxAttributeInitializerMultipleElementsNoCrash.js]
import { jsx as _jsx } from "react/jsx-runtime";
const a = (_jsx("div", { attr: _jsx("span", {}) }), _jsx("span", {})) / > ;
17 changes: 13 additions & 4 deletions tsc/testdata/baselines/reference/compiler/jsxAttributeValueBinaryExpression.errors.txt
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@@ -1,17 +1,26 @@
jsxAttributeValueBinaryExpression.tsx(1,1): error TS2657: JSX expressions must have one parent element.
jsxAttributeValueBinaryExpression.tsx(1,2): error TS2304: Cannot find name 'X'.
jsxAttributeValueBinaryExpression.tsx(1,6): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
jsxAttributeValueBinaryExpression.tsx(1,6): error TS2657: JSX expressions must have one parent element.
jsxAttributeValueBinaryExpression.tsx(1,10): error TS1003: Identifier expected.
jsxAttributeValueBinaryExpression.tsx(1,10): error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
jsxAttributeValueBinaryExpression.tsx(1,16): error TS1109: Expression expected.
jsxAttributeValueBinaryExpression.tsx(1,17): error TS1109: Expression expected.


==== jsxAttributeValueBinaryExpression.tsx (4 errors) ====
==== jsxAttributeValueBinaryExpression.tsx (7 errors) ====
<X a=<b/><c/> />
~~~~~~~~~~~~~
!!! error TS2657: JSX expressions must have one parent element.
~
!!! error TS2304: Cannot find name 'X'.
~~~~
!!! error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
~~~~~~~~
!!! error TS2657: JSX expressions must have one parent element.
~
!!! error TS1003: Identifier expected.
~~~~
!!! error TS7026: JSX element implicitly has type 'any' because no interface 'JSX.IntrinsicElements' exists.
~
!!! error TS1109: Expression expected.

!!! error TS1109: Expression expected.

3 changes: 2 additions & 1 deletion tsc/testdata/baselines/reference/compiler/jsxAttributeValueBinaryExpression.js
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Expand Up @@ -6,4 +6,5 @@

//// [jsxAttributeValueBinaryExpression.jsx]
"use strict";
<X a=<b />, <c />/>;
(<X a=<b />/>, <c />) / >
;
7 changes: 7 additions & 0 deletions tsc/testdata/tests/cases/compiler/jsxAttributeInitializerMultipleElementsNoCrash.tsx
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@@ -0,0 +1,7 @@
// @jsx: react,react-jsx
// @noTypesAndSymbols: true

declare namespace JSX { interface IntrinsicElements { [x: string]: any } }
declare const React: any;

const a = <div attr=<span /><span /> />;