syntax: Fix duplicate attributes on module files

The outer attributes were manually appended when a module file was parsed, but
the attributes were also added higher up the stack of parsing (when the module
finished parsing). This removes the append in parsing the module file.

Closes #13826

Author: alexcrichton

src/libsyntax/parse/parser.rs

@@ -4155,14 +4155,11 @@ impl<'a> Parser<'a> {
             }
         };
 
-        self.eval_src_mod_from_path(file_path,
-                                    outer_attrs.iter().map(|x| *x).collect(),
-                                    id_sp)
+        self.eval_src_mod_from_path(file_path, id_sp)
     }
 
     fn eval_src_mod_from_path(&mut self,
                               path: Path,
-                              outer_attrs: Vec<ast::Attribute> ,
                               id_sp: Span) -> (ast::Item_, Vec<ast::Attribute> ) {
         let mut included_mod_stack = self.sess.included_mod_stack.borrow_mut();
         match included_mod_stack.iter().position(|p| *p == path) {
@@ -4187,8 +4184,7 @@ impl<'a> Parser<'a> {
                                      &path,
                                      id_sp);
         let mod_inner_lo = p0.span.lo;
-        let (inner, next) = p0.parse_inner_attrs_and_next();
-        let mod_attrs = outer_attrs.append(inner.as_slice());
+        let (mod_attrs, next) = p0.parse_inner_attrs_and_next();
         let first_item_outer_attrs = next;
         let m0 = p0.parse_mod_items(token::EOF, first_item_outer_attrs, mod_inner_lo);
         self.sess.included_mod_stack.borrow_mut().pop();