resolve: Do not call resolve_macro_path from late resolution

`maybe_resolve_path` is less precise in corner cases, but it's only used for diagnostics and error recovery, so it's good enough.

Author: petrochenkov

compiler/rustc_resolve/src/diagnostics.rs

@@ -1047,7 +1047,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
                             let Ok((Some(ext), _)) = this.reborrow().resolve_macro_path(
                                 derive,
-                                Some(MacroKind::Derive),
+                                MacroKind::Derive,
                                 parent_scope,
                                 false,
                                 false,

compiler/rustc_resolve/src/ident.rs

@@ -458,7 +458,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                             let parent_scope = &ParentScope { derives: &[], ..*parent_scope };
                             match this.reborrow().resolve_macro_path(
                                 derive,
-                                Some(MacroKind::Derive),
+                                MacroKind::Derive,
                                 parent_scope,
                                 true,
                                 force,

compiler/rustc_resolve/src/late.rs

@@ -4315,7 +4315,6 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
             qself,
             path,
             ns,
-            path_span,
             source.defer_to_typeck(),
             finalize,
             source,
@@ -4438,7 +4437,6 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         qself: &Option<Box<QSelf>>,
         path: &[Segment],
         primary_ns: Namespace,
-        span: Span,
         defer_to_typeck: bool,
         finalize: Finalize,
         source: PathSource<'_, 'ast, 'ra>,
@@ -4463,21 +4461,11 @@ impl<'a, 'ast, 'ra, 'tcx> LateResolutionVisitor<'a, 'ast, 'ra, 'tcx> {
         }
 
         assert!(primary_ns != MacroNS);
-
-        if qself.is_none() {
-            let path_seg = |seg: &Segment| PathSegment::from_ident(seg.ident);
-            let path = Path { segments: path.iter().map(path_seg).collect(), span, tokens: None };
-            if let Ok((_, res)) = self.r.cm().resolve_macro_path(
-                &path,
-                None,
-                &self.parent_scope,
-                false,
-                false,
-                None,
-                None,
-            ) {
-                return Ok(Some(PartialRes::new(res)));
-            }
+        if qself.is_none()
+            && let PathResult::NonModule(res) =
+                self.r.cm().maybe_resolve_path(path, Some(MacroNS), &self.parent_scope, None)
+        {
+            return Ok(Some(res));
         }
 
         Ok(fin_res)

compiler/rustc_resolve/src/macros.rs

@@ -405,7 +405,7 @@ impl<'ra, 'tcx> ResolverExpand for Resolver<'ra, 'tcx> {
                 resolution.exts = Some(
                     match self.cm().resolve_macro_path(
                         &resolution.path,
-                        Some(MacroKind::Derive),
+                        MacroKind::Derive,
                         &parent_scope,
                         true,
                         force,
@@ -570,7 +570,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     ) -> Result<(Arc<SyntaxExtension>, Res), Indeterminate> {
         let (ext, res) = match self.cm().resolve_macro_or_delegation_path(
             path,
-            Some(kind),
+            kind,
             parent_scope,
             true,
             force,
@@ -716,7 +716,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     pub(crate) fn resolve_macro_path<'r>(
         self: CmResolver<'r, 'ra, 'tcx>,
         path: &ast::Path,
-        kind: Option<MacroKind>,
+        kind: MacroKind,
         parent_scope: &ParentScope<'ra>,
         trace: bool,
         force: bool,
@@ -739,7 +739,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
     fn resolve_macro_or_delegation_path<'r>(
         mut self: CmResolver<'r, 'ra, 'tcx>,
         ast_path: &ast::Path,
-        kind: Option<MacroKind>,
+        kind: MacroKind,
         parent_scope: &ParentScope<'ra>,
         trace: bool,
         force: bool,
@@ -753,7 +753,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
 
         // Possibly apply the macro helper hack
         if deleg_impl.is_none()
-            && kind == Some(MacroKind::Bang)
+            && kind == MacroKind::Bang
             && let [segment] = path.as_slice()
             && segment.ident.span.ctxt().outer_expn_data().local_inner_macros
         {
@@ -781,7 +781,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             };
 
             if trace {
-                let kind = kind.expect("macro kind must be specified if tracing is enabled");
                 // FIXME: Should be an output of Speculative Resolution.
                 self.multi_segment_macro_resolutions.borrow_mut().push((
                     path,
@@ -796,10 +795,9 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             self.prohibit_imported_non_macro_attrs(None, res.ok(), path_span);
             res
         } else {
-            let scope_set = kind.map_or(ScopeSet::All(MacroNS), ScopeSet::Macro);
             let binding = self.reborrow().early_resolve_ident_in_lexical_scope(
                 path[0].ident,
-                scope_set,
+                ScopeSet::Macro(kind),
                 parent_scope,
                 None,
                 force,
@@ -811,7 +809,6 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
             }
 
             if trace {
-                let kind = kind.expect("macro kind must be specified if tracing is enabled");
                 // FIXME: Should be an output of Speculative Resolution.
                 self.single_segment_macro_resolutions.borrow_mut().push((
                     path[0].ident,
@@ -843,7 +840,7 @@ impl<'ra, 'tcx> Resolver<'ra, 'tcx> {
                 _ => None,
             },
             None => self.get_macro(res).map(|macro_data| match kind {
-                Some(MacroKind::Attr) if let Some(ref ext) = macro_data.attr_ext => Arc::clone(ext),
+                MacroKind::Attr if let Some(ref ext) = macro_data.attr_ext => Arc::clone(ext),
                 _ => Arc::clone(&macro_data.ext),
             }),
         };