fix(js_parser): desambigaute JSX and const type param of arrow function

biomejs · Nov 23, 2023 · 38a29ab · 38a29ab
1 parent 45e29db
commit 38a29ab
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Showing 5 changed files with 375 additions and 175 deletions.
diff --git a/crates/biome_js_parser/src/syntax/function.rs b/crates/biome_js_parser/src/syntax/function.rs
@@ -754,29 +754,34 @@ fn is_parenthesized_arrow_function_expression_impl(
         }
         // potential start of type parameters
         T![<] => {
-            if is_nth_at_type_parameter_modifier(p, n + 1) && !JsSyntaxFeature::Jsx.is_supported(p)
-            {
-                // <const T>...
-                IsParenthesizedArrowFunctionExpression::True
-            } else if !is_nth_at_identifier(p, n + 1) {
-                // <5...
-                IsParenthesizedArrowFunctionExpression::False
-            }
             // test jsx jsx_type_arguments
             // // These may look like a valid arrows but are JSX
             // <A extends>() =</A>;
             // <A extends="B">() =</A>;
             // <A extends ok>() =</A>;
+            // <const A>() =</const>;
 
             // test tsx tsx_type_arguments
             // // These are valid type arguments
+            // <A,>() => {};
+            // <const A,>() => {};
             // <A extends B>() => {};
             // <A=string>() => {};
             // <A, B>() => {};
-            // <A extends B<C>>() => {}
-
-            // <a... JSX override
-            else if JsSyntaxFeature::Jsx.is_supported(p) {
+            // <A extends B<C>>() => {};
+
+            if JsSyntaxFeature::Jsx.is_supported(p) {
+                // Disambiguate between JSX and type parameters
+                // Type parameters of arrow functions accept only the `const` modifier.
+                let n = if p.nth(n + 1) == T![const] {
+                    n + 1
+                } else {
+                    n
+                };
+                if !is_nth_at_identifier(p, n + 1) {
+                    // <5...
+                    return IsParenthesizedArrowFunctionExpression::False;
+                };
                 match p.nth(n + 2) {
                     T![extends] => {
                         // `<a extends=` OR `<a extends>` is a JSX start element
@@ -796,6 +801,12 @@ fn is_parenthesized_arrow_function_expression_impl(
                     T![=] | T![,] => IsParenthesizedArrowFunctionExpression::True,
                     _ => IsParenthesizedArrowFunctionExpression::False,
                 }
+            } else if is_nth_at_type_parameter_modifier(p, n + 1) {
+                // <const T>...
+                IsParenthesizedArrowFunctionExpression::True
+            } else if !is_nth_at_identifier(p, n + 1) {
+                // <5...
+                IsParenthesizedArrowFunctionExpression::False
             } else {
                 // <a...
                 IsParenthesizedArrowFunctionExpression::Unknown

diff --git a/crates/biome_js_parser/test_data/inline/ok/jsx_type_arguments.jsx b/crates/biome_js_parser/test_data/inline/ok/jsx_type_arguments.jsx
@@ -2,3 +2,4 @@
 <A extends>() =</A>;
 <A extends="B">() =</A>;
 <A extends ok>() =</A>;
+<const A>() =</const>;
diff --git a/crates/biome_js_parser/test_data/inline/ok/jsx_type_arguments.rast b/crates/biome_js_parser/test_data/inline/ok/jsx_type_arguments.rast
@@ -122,15 +122,51 @@ JsModule {
             },
             semicolon_token: [email protected] ";" [] [],
         },
+        JsExpressionStatement {
+            expression: JsxTagExpression {
+                tag: JsxElement {
+                    opening_element: JsxOpeningElement {
+                        l_angle_token: [email protected] "<" [Newline("\n")] [],
+                        name: JsxName {
+                            value_token: [email protected] "const" [] [Whitespace(" ")],
+                        },
+                        type_arguments: missing (optional),
+                        attributes: JsxAttributeList [
+                            JsxAttribute {
+                                name: JsxName {
+                                    value_token: [email protected] "A" [] [],
+                                },
+                                initializer: missing (optional),
+                            },
+                        ],
+                        r_angle_token: [email protected] ">" [] [],
+                    },
+                    children: JsxChildList [
+                        JsxText {
+                            value_token: [email protected] "() =" [] [],
+                        },
+                    ],
+                    closing_element: JsxClosingElement {
+                        l_angle_token: [email protected] "<" [] [],
+                        slash_token: [email protected] "/" [] [],
+                        name: JsxName {
+                            value_token: [email protected] "const" [] [],
+                        },
+                        r_angle_token: [email protected] ">" [] [],
+                    },
+                },
+            },
+            semicolon_token: [email protected] ";" [] [],
+        },
     ],
-    eof_token: EOF@119..120 "" [Newline("\n")] [],
+    eof_token: EOF@142..143 "" [Newline("\n")] [],
 }
 
-0: JS_MODULE@0..120
+0: JS_MODULE@0..143
   0: (empty)
   1: (empty)
   2: [email protected]
-  3: JS_MODULE_ITEM_LIST@0..119
+  3: JS_MODULE_ITEM_LIST@0..142
     0: [email protected]
       0: [email protected]
         0: [email protected]
@@ -210,4 +246,28 @@ JsModule {
               0: [email protected] "A" [] []
             3: [email protected] ">" [] []
       1: [email protected] ";" [] []
-  4: [email protected] "" [Newline("\n")] []
+    3: [email protected]
+      0: [email protected]
+        0: [email protected]
+          0: [email protected]
+            0: [email protected] "<" [Newline("\n")] []
+            1: [email protected]
+              0: [email protected] "const" [] [Whitespace(" ")]
+            2: (empty)
+            3: [email protected]
+              0: [email protected]
+                0: [email protected]
+                  0: [email protected] "A" [] []
+                1: (empty)
+            4: [email protected] ">" [] []
+          1: [email protected]
+            0: [email protected]
+              0: [email protected] "() =" [] []
+          2: [email protected]
+            0: [email protected] "<" [] []
+            1: [email protected] "/" [] []
+            2: [email protected]
+              0: [email protected] "const" [] []
+            3: [email protected] ">" [] []
+      1: [email protected] ";" [] []
+  4: [email protected] "" [Newline("\n")] []