refactor: prepare to associate multiple spans with a module.

compiler/rustc_ast/src/ast.rs

@@ -2317,11 +2317,24 @@ pub enum ModKind {
     /// or with definition outlined to a separate file `mod foo;` and already loaded from it.
     /// The inner span is from the first token past `{` to the last token until `}`,
     /// or from the first to the last token in the loaded file.
-    Loaded(Vec<P<Item>>, Inline, Span),
+    Loaded(Vec<P<Item>>, Inline, ModSpans),
     /// Module with definition outlined to a separate file `mod foo;` but not yet loaded from it.
     Unloaded,
 }
 
+#[derive(Clone, Encodable, Decodable, Debug)]
+pub struct ModSpans {
+    /// `inner_span` covers the body of the module; for a file module, its the whole file.
+    /// For an inline module, its the span inside the `{ ... }`, not including the curly braces.
+    pub inner_span: Span,
+}
+
+impl Default for ModSpans {
+    fn default() -> ModSpans {
+        ModSpans { inner_span: Default::default() }
+    }
+}
+
 /// Foreign module declaration.
 ///
 /// E.g., `extern { .. }` or `extern "C" { .. }`.

compiler/rustc_ast/src/mut_visit.rs

@@ -1009,7 +1009,7 @@ pub fn noop_visit_item_kind<T: MutVisitor>(kind: &mut ItemKind, vis: &mut T) {
         ItemKind::Mod(unsafety, mod_kind) => {
             visit_unsafety(unsafety, vis);
             match mod_kind {
-                ModKind::Loaded(items, _inline, inner_span) => {
+                ModKind::Loaded(items, _inline, ModSpans { inner_span }) => {
                     vis.visit_span(inner_span);
                     items.flat_map_in_place(|item| vis.flat_map_item(item));
                 }

compiler/rustc_ast_lowering/src/item.rs

@@ -263,7 +263,7 @@ impl<'hir> LoweringContext<'_, 'hir> {
                 })
             }
             ItemKind::Mod(_, ref mod_kind) => match mod_kind {
-                ModKind::Loaded(items, _, inner_span) => {
+                ModKind::Loaded(items, _, ModSpans { inner_span }) => {
                     hir::ItemKind::Mod(self.lower_mod(items, *inner_span))
                 }
                 ModKind::Unloaded => panic!("`mod` items should have been loaded by now"),

compiler/rustc_builtin_macros/src/test_harness.rs

@@ -129,7 +129,9 @@ impl<'a> MutVisitor for TestHarnessGenerator<'a> {
 
         // We don't want to recurse into anything other than mods, since
         // mods or tests inside of functions will break things
-        if let ast::ItemKind::Mod(_, ModKind::Loaded(.., span)) = item.kind {
+        if let ast::ItemKind::Mod(_, ModKind::Loaded(.., ast::ModSpans { inner_span: span })) =
+            item.kind
+        {
             let prev_tests = mem::take(&mut self.tests);
             noop_visit_item_kind(&mut item.kind, self);
             self.add_test_cases(item.id, span, prev_tests);

compiler/rustc_expand/src/expand.rs

@@ -12,8 +12,8 @@ use rustc_ast::token;
 use rustc_ast::tokenstream::TokenStream;
 use rustc_ast::visit::{self, AssocCtxt, Visitor};
 use rustc_ast::{AssocItemKind, AstLike, AstLikeWrapper, AttrStyle, ExprKind, ForeignItemKind};
-use rustc_ast::{Inline, ItemKind, MacArgs, MacStmtStyle, MetaItemKind, ModKind, NestedMetaItem};
-use rustc_ast::{NodeId, PatKind, StmtKind, TyKind};
+use rustc_ast::{Inline, ItemKind, MacArgs, MacStmtStyle, MetaItemKind, ModKind, ModSpans};
+use rustc_ast::{NestedMetaItem, NodeId, PatKind, StmtKind, TyKind};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::map_in_place::MapInPlace;
 use rustc_data_structures::sync::Lrc;
@@ -1112,7 +1112,7 @@ impl InvocationCollectorNode for P<ast::Item> {
                     );
                 }
 
-                *mod_kind = ModKind::Loaded(items, Inline::No, inner_span);
+                *mod_kind = ModKind::Loaded(items, Inline::No, ModSpans { inner_span });
                 node.attrs = attrs;
                 if node.attrs.len() > old_attrs_len {
                     // If we loaded an out-of-line module and added some inner attributes,

compiler/rustc_expand/src/module.rs

@@ -1,6 +1,6 @@
 use crate::base::ModuleData;
 use rustc_ast::ptr::P;
-use rustc_ast::{token, Attribute, Inline, Item};
+use rustc_ast::{token, Attribute, Inline, Item, ModSpans};
 use rustc_errors::{struct_span_err, DiagnosticBuilder, ErrorGuaranteed};
 use rustc_parse::new_parser_from_file;
 use rustc_parse::validate_attr;
@@ -69,7 +69,7 @@ crate fn parse_external_mod(
         (items, inner_span, mp.file_path)
     };
     // (1) ...instead, we return a dummy module.
-    let (items, inner_span, file_path) =
+    let (items, ModSpans { inner_span }, file_path) =
         result.map_err(|err| err.report(sess, span)).unwrap_or_default();
 
     // Extract the directory path for submodules of the module.

compiler/rustc_parse/src/parser/item.rs

@@ -26,7 +26,8 @@ use tracing::debug;
 impl<'a> Parser<'a> {
     /// Parses a source module as a crate. This is the main entry point for the parser.
     pub fn parse_crate_mod(&mut self) -> PResult<'a, ast::Crate> {
-        let (attrs, items, span) = self.parse_mod(&token::Eof)?;
+        let (attrs, items, spans) = self.parse_mod(&token::Eof)?;
+        let span = spans.inner_span;
         Ok(ast::Crate { attrs, items, span, id: DUMMY_NODE_ID, is_placeholder: false })
     }
 
@@ -51,7 +52,7 @@ impl<'a> Parser<'a> {
     pub fn parse_mod(
         &mut self,
         term: &TokenKind,
-    ) -> PResult<'a, (Vec<Attribute>, Vec<P<Item>>, Span)> {
+    ) -> PResult<'a, (Vec<Attribute>, Vec<P<Item>>, ModSpans)> {
         let lo = self.token.span;
         let attrs = self.parse_inner_attributes()?;
 
@@ -71,7 +72,7 @@ impl<'a> Parser<'a> {
             }
         }
 
-        Ok((attrs, items, lo.to(self.prev_token.span)))
+        Ok((attrs, items, ModSpans { inner_span: lo.to(self.prev_token.span) }))
     }
 }
 

src/tools/rustfmt/src/parse/parser.rs

@@ -113,7 +113,7 @@ impl<'a> Parser<'a> {
         let result = catch_unwind(AssertUnwindSafe(|| {
             let mut parser = new_parser_from_file(sess.inner(), path, Some(span));
             match parser.parse_mod(&TokenKind::Eof) {
-                Ok(result) => Some(result),
+                Ok((a, i, ast::ModSpans { inner_span })) => Some((a, i, inner_span)),
                 Err(mut e) => {
                     e.emit();
                     if sess.can_reset_errors() {

src/tools/rustfmt/src/visitor.rs

@@ -915,7 +915,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
         self.push_str(&ident_str);
 
-        if let ast::ModKind::Loaded(ref items, ast::Inline::Yes, inner_span) = mod_kind {
+        if let ast::ModKind::Loaded(ref items, ast::Inline::Yes, ast::ModSpans{ inner_span }) = mod_kind {
             match self.config.brace_style() {
                 BraceStyle::AlwaysNextLine => {
                     let indent_str = self.block_indent.to_string_with_newline(self.config);