Relax Module lifetimes and defer cloning

Author: camsteffen

src/modules.rs

@@ -54,6 +54,18 @@ impl<'a> Module<'a> {
     pub(crate) fn attrs(&self) -> &[ast::Attribute] {
         &self.inner_attr
     }
+
+    pub(crate) fn to_owned(&self) -> Module<'static> {
+        Module {
+            ast_mod_kind: self
+                .ast_mod_kind
+                .as_ref()
+                .map(|i| Cow::Owned((**i).clone())),
+            items: Cow::Owned((&*self.items).clone()),
+            inner_attr: self.inner_attr.clone(),
+            span: self.span,
+        }
+    }
 }
 
 /// Maps each module to the corresponding file.
@@ -172,7 +184,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                     &item,
                     Module::new(
                         span,
-                        Some(Cow::Owned(sub_mod_kind.clone())),
+                        Some(Cow::Borrowed(sub_mod_kind)),
                         Cow::Owned(ThinVec::new()),
                         &[],
                     ),
@@ -185,7 +197,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     /// Visit modules from AST.
     fn visit_mod_from_ast(
         &mut self,
-        items: &'ast [rustc_ast::ptr::P<ast::Item>],
+        items: &[rustc_ast::ptr::P<ast::Item>],
     ) -> Result<(), ModuleResolutionError> {
         for item in items {
             if is_cfg_if(item) {
@@ -211,7 +223,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     fn visit_sub_mod(
         &mut self,
         item: &'c ast::Item,
-        sub_mod: Module<'ast>,
+        sub_mod: Module<'_>,
     ) -> Result<(), ModuleResolutionError> {
         let old_directory = self.directory.clone();
         let sub_mod_kind = self.peek_sub_mod(item, &sub_mod)?;
@@ -227,7 +239,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     fn peek_sub_mod(
         &self,
         item: &'c ast::Item,
-        sub_mod: &Module<'ast>,
+        sub_mod: &Module<'_>,
     ) -> Result<Option<SubModKind<'c, 'ast>>, ModuleResolutionError> {
         if contains_skip(&item.attrs) {
             return Ok(None);
@@ -267,7 +279,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
 
     fn visit_sub_mod_inner(
         &mut self,
-        sub_mod: Module<'ast>,
+        sub_mod: Module<'_>,
         sub_mod_kind: SubModKind<'c, 'ast>,
     ) -> Result<(), ModuleResolutionError> {
         match sub_mod_kind {
@@ -297,7 +309,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
 
     fn visit_sub_mod_after_directory_update(
         &mut self,
-        sub_mod: Module<'ast>,
+        sub_mod: Module<'_>,
         directory: Option<Directory>,
     ) -> Result<(), ModuleResolutionError> {
         if let Some(directory) = directory {
@@ -319,7 +331,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
         &self,
         mod_name: symbol::Ident,
         attrs: &[ast::Attribute],
-        sub_mod: &Module<'ast>,
+        sub_mod: &Module<'_>,
     ) -> Result<Option<SubModKind<'c, 'ast>>, ModuleResolutionError> {
         let relative = match self.directory.ownership {
             DirectoryOwnership::Owned { relative } => relative,
@@ -373,7 +385,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                         return Ok(None);
                     } else {
                         if should_insert {
-                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
+                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.to_owned()));
                         }
                         return Ok(Some(SubModKind::MultiExternal(mods_outside_ast)));
                     }
@@ -404,7 +416,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                             ),
                         ));
                         if should_insert {
-                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
+                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.to_owned()));
                         }
                         Ok(Some(SubModKind::MultiExternal(mods_outside_ast)))
                     }
@@ -418,7 +430,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                     }),
                     Err(..) => {
                         if should_insert {
-                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.clone()));
+                            mods_outside_ast.push((file_path, dir_ownership, sub_mod.to_owned()));
                         }
                         Ok(Some(SubModKind::MultiExternal(mods_outside_ast)))
                     }
@@ -489,7 +501,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
     fn find_mods_outside_of_ast(
         &self,
         attrs: &[ast::Attribute],
-        sub_mod: &Module<'ast>,
+        sub_mod: &Module<'_>,
     ) -> Vec<(PathBuf, DirectoryOwnership, Module<'ast>)> {
         // Filter nested path, like `#[cfg_attr(feature = "foo", path = "bar.rs")]`.
         let mut path_visitor = visitor::PathVisitor::default();
@@ -510,7 +522,7 @@ impl<'ast, 'sess, 'c> ModResolver<'ast, 'sess> {
                 result.push((
                     actual_path,
                     DirectoryOwnership::Owned { relative: None },
-                    sub_mod.clone(),
+                    sub_mod.to_owned(),
                 ));
                 continue;
             }