feat: allow attribute items in type parameters

Author: amaanq

grammar.js

@@ -542,13 +542,16 @@ module.exports = grammar({
 
     type_parameters: $ => prec(1, seq(
       '<',
-      sepBy1(',', choice(
-        $.lifetime,
-        $.metavariable,
-        $._type_identifier,
-        $.constrained_type_parameter,
-        $.optional_type_parameter,
-        $.const_parameter,
+      sepBy1(',', seq(
+        repeat($.attribute_item),
+        choice(
+          $.lifetime,
+          $.metavariable,
+          $._type_identifier,
+          $.constrained_type_parameter,
+          $.optional_type_parameter,
+          $.const_parameter,
+        ),
       )),
       optional(','),
       '>',

test/corpus/declarations.txt

@@ -667,6 +667,7 @@ struct A<B> {}
 struct C<'a, 'b> {}
 struct C<'a,> {}
 struct D<const SIZE: usize> {}
+struct E<#[attr] T> {}
 
 --------------------------------------------------------------------------------
 
@@ -696,6 +697,14 @@ struct D<const SIZE: usize> {}
       (const_parameter
         name: (identifier)
         type: (primitive_type)))
+    body: (field_declaration_list))
+  (struct_item
+    name: (type_identifier)
+    type_parameters: (type_parameters
+      (attribute_item
+        (attribute
+          (identifier)))
+      (type_identifier))
     body: (field_declaration_list)))
 
 ================================================================================
@@ -1668,7 +1677,7 @@ fn univariant(this: &impl ?Sized, that: &(impl LayoutCalculator + ?Sized)) {}
     (block)))
 
 ================================================================================
-Trait bounds in type in trait
+Trait bounds in type arguments in trait
 ================================================================================
 
 impl<T: AstDeref<Target: HasNodeId>> HasNodeId for T {}