fix(compiler): Supply correct locations for attributes (#2048)

Author: ospencer

compiler/src/parsing/parser.mly

@@ -555,10 +555,10 @@ attribute_arguments:
   | lparen lseparated_list(comma, attribute_argument) rparen { $2 }
 
 attribute:
-  | AT id_str loption(attribute_arguments) opt_eols { Attribute.mk ~loc:(to_loc $loc) $2 $3 }
+  | AT id_str loption(attribute_arguments) { Attribute.mk ~loc:(to_loc $loc) $2 $3 }
 
 attributes:
-  | attribute* { $1 }
+  | terminated(attribute, opt_eols)* { $1 }
 
 let_expr:
   | attributes LET REC value_binds { Expression.let_ ~loc:(to_loc $sloc) ~core_loc:(to_loc (fst $loc($2), snd $loc)) ~attributes:$1 Recursive Immutable $4 }

compiler/test/grainfmt/comments.expected.gr

@@ -330,16 +330,15 @@ foo += /* foo */ /* foo */ 1
 foo += /* foo */ /* foo */ 1
 
 {
-  @attr
+  @attr // foo
   let // foo
   _ = 1
   @attr(
     "foo", /* doo */
     "foo",
     // foo
     // goo
-    // bar
-  )
+  ) // bar
   let /* doo */ // foo
   // goo
   // bar
@@ -599,15 +598,14 @@ provide {
   module Foo as /* Foo */ /* as */ Bar,
 }
 
-@attr
+@attr // foo
 let _ = 1
 @attr(
   "foo", /* doo */
   "foo",
   // foo
   // goo
-  // bar
-)
+) // bar
 let _ = 1
 
 provide /* provide */ enum Foo {