fix(parser): allow parenthesized JSX comma expressions with preserve_parens=false (#26524)

Allow parenthesized comma expressions such as `<A>{(a, b)}</A>` and `<A x={(a, b)} />` when `preserve_parens` is false.

Compare the sequence expression's start with the first token's start to retain the grouping distinction after parentheses are omitted from the AST. Ungrouped comma expressions such as `{a, b}` and `{(a, b), c}` remain invalid.

crates/oxc_parser/src/jsx/mod.rs

@@ -382,9 +382,11 @@ impl<'a, C: Config> ParserImpl<'a, C> {
             //                                            ^^^^^^^^^^^^^ span
             JSXExpression::new_empty_expression(Span::new(span.start + 1, span.end - 1), self)
         } else {
+            let expr_start = self.cur_start();
             let expr = JSXExpression::from(self.parse_expr());
-            // JSX expressions may not use the comma operator.
-            if matches!(expr, JSXExpression::SequenceExpression(_)) {
+            // JSX expressions may not use an unparenthesized comma operator.
+            if matches!(&expr, JSXExpression::SequenceExpression(sequence) if sequence.span.start == expr_start)
+            {
                 self.error(diagnostics::jsx_expressions_may_not_use_the_comma_operator(
                     expr.span(),
                 ));

tasks/coverage/misc/fail/jsx-unparenthesized-comma.jsx

@@ -0,0 +1,4 @@
+<A>{a, b}</A>;
+<A x={a, b} />;
+<A>{(a, b), c}</A>;
+<A x={(a, b), c} />;

tasks/coverage/misc/pass/jsx-parenthesized-comma.jsx

@@ -0,0 +1,6 @@
+<A>{(a, b)}</A>;
+<A x={(a, b)} />;
+<A>{((a, b))}</A>;
+<A x={((a, b))} />;
+<A>{((a, b), c)}</A>;
+<A x={((a, b), c)} />;

tasks/coverage/snapshots/codegen_misc.snap

@@ -1,3 +1,3 @@
 codegen_misc Summary:
-AST Parsed     : 98/98 (100.00%)
-Positive Passed: 98/98 (100.00%)
+AST Parsed     : 99/99 (100.00%)
+Positive Passed: 99/99 (100.00%)

tasks/coverage/snapshots/formatter_misc.snap

@@ -1,3 +1,3 @@
 formatter_misc Summary:
-AST Parsed     : 98/98 (100.00%)
-Positive Passed: 98/98 (100.00%)
+AST Parsed     : 99/99 (100.00%)
+Positive Passed: 99/99 (100.00%)

tasks/coverage/snapshots/lexer_misc.snap

@@ -1,3 +1,3 @@
 lexer_misc Summary:
-AST Parsed     : 300/300 (100.00%)
-Positive Passed: 300/300 (100.00%)
+AST Parsed     : 302/302 (100.00%)
+Positive Passed: 302/302 (100.00%)

tasks/coverage/snapshots/parser_misc.snap

@@ -1,7 +1,7 @@
 parser_misc Summary:
-AST Parsed     : 98/98 (100.00%)
-Positive Passed: 98/98 (100.00%)
-Negative Passed: 202/202 (100.00%)
+AST Parsed     : 99/99 (100.00%)
+Positive Passed: 99/99 (100.00%)
+Negative Passed: 203/203 (100.00%)
 
   × Cannot assign to 'arguments' in strict mode
    ╭─[misc/fail/arguments-eval-ambient.ts:2:13]
@@ -939,6 +939,40 @@ Negative Passed: 202/202 (100.00%)
    ╰────
   help: JSX syntax is disabled and should be enabled via the parser options
 
+  × TS(18007): JSX expressions may not use the comma operator
+   ╭─[misc/fail/jsx-unparenthesized-comma.jsx:1:5]
+ 1 │ <A>{a, b}</A>;
+   ·     ────
+ 2 │ <A x={a, b} />;
+   ╰────
+  help: Did you mean to write an array?
+
+  × TS(18007): JSX expressions may not use the comma operator
+   ╭─[misc/fail/jsx-unparenthesized-comma.jsx:2:7]
+ 1 │ <A>{a, b}</A>;
+ 2 │ <A x={a, b} />;
+   ·       ────
+ 3 │ <A>{(a, b), c}</A>;
+   ╰────
+  help: Did you mean to write an array?
+
+  × TS(18007): JSX expressions may not use the comma operator
+   ╭─[misc/fail/jsx-unparenthesized-comma.jsx:3:5]
+ 2 │ <A x={a, b} />;
+ 3 │ <A>{(a, b), c}</A>;
+   ·     ─────────
+ 4 │ <A x={(a, b), c} />;
+   ╰────
+  help: Did you mean to write an array?
+
+  × TS(18007): JSX expressions may not use the comma operator
+   ╭─[misc/fail/jsx-unparenthesized-comma.jsx:4:7]
+ 3 │ <A>{(a, b), c}</A>;
+ 4 │ <A x={(a, b), c} />;
+   ·       ─────────
+   ╰────
+  help: Did you mean to write an array?
+
   × The keyword 'let' is reserved
    ╭─[misc/fail/let-member-expression.js:4:1]
  3 │ 

tasks/coverage/snapshots/semantic_misc.snap

@@ -1,6 +1,6 @@
 semantic_misc Summary:
-AST Parsed     : 98/98 (100.00%)
-Positive Passed: 94/98 (95.92%)
+AST Parsed     : 99/99 (100.00%)
+Positive Passed: 95/99 (95.96%)
 semantic Error: tasks/coverage/misc/pass/declare-let-private.ts
 Bindings mismatch:
 after transform: ScopeId(0): ["private"]

tasks/coverage/snapshots/transformer_misc.snap

@@ -1,3 +1,3 @@
 transformer_misc Summary:
-AST Parsed     : 98/98 (100.00%)
-Positive Passed: 98/98 (100.00%)
+AST Parsed     : 99/99 (100.00%)
+Positive Passed: 99/99 (100.00%)