fix: Handle included files better in IDE layer

This does not fully fix things, but it introduces a function that can be used to fix occurences.
When using `to_def` functionality, the input node needs to come from the macro expanded include, not the real file that was included.
This does unfortunately add more caller burden, but there is not really a way around it.

crates/hir/src/semantics.rs

@@ -769,6 +769,31 @@ impl<'db> SemanticsImpl<'db> {
         })
     }
 
+    /// Descends the token into the include expansion, if its file is an included file.
+    pub fn descend_token_into_include_expansion(
+        &self,
+        tok: InRealFile<SyntaxToken>,
+    ) -> InFile<SyntaxToken> {
+        let Some(include) =
+            self.s2d_cache.borrow_mut().get_or_insert_include_for(self.db, tok.file_id)
+        else {
+            return tok.into();
+        };
+        let span = self.db.real_span_map(tok.file_id).span_for_range(tok.value.text_range());
+        let Some(InMacroFile { file_id, value: mut mapped_tokens }) = self.with_ctx(|ctx| {
+            Some(
+                ctx.cache
+                    .get_or_insert_expansion(ctx.db, include)
+                    .map_range_down(span)?
+                    .map(SmallVec::<[_; 2]>::from_iter),
+            )
+        }) else {
+            return tok.into();
+        };
+        // We should only get one result at most
+        mapped_tokens.pop().map_or_else(|| tok.into(), |(tok, _)| InFile::new(file_id.into(), tok))
+    }
+
     /// Maps a node down by mapping its first and last token down.
     pub fn descend_node_into_attributes<N: AstNode>(&self, node: N) -> SmallVec<[N; 1]> {
         // This might not be the correct way to do this, but it works for now
@@ -1528,11 +1553,9 @@ impl<'db> SemanticsImpl<'db> {
     }
 
     pub fn resolve_macro_call2(&self, macro_call: InFile<&ast::MacroCall>) -> Option<Macro> {
-        self.with_ctx(|ctx| {
-            ctx.macro_call_to_macro_call(macro_call)
-                .and_then(|call| macro_call_to_macro_id(ctx, call))
-                .map(Into::into)
-        })
+        self.to_def2(macro_call)
+            .and_then(|call| self.with_ctx(|ctx| macro_call_to_macro_id(ctx, call)))
+            .map(Into::into)
     }
 
     pub fn is_proc_macro_call(&self, macro_call: InFile<&ast::MacroCall>) -> bool {
@@ -1647,6 +1670,10 @@ impl<'db> SemanticsImpl<'db> {
         T::to_def(self, src)
     }
 
+    pub fn to_def2<T: ToDef>(&self, src: InFile<&T>) -> Option<T::Def> {
+        T::to_def(self, src)
+    }
+
     fn file_to_module_defs(&self, file: FileId) -> impl Iterator<Item = Module> {
         self.with_ctx(|ctx| ctx.file_to_def(file).to_owned()).into_iter().map(Module::from)
     }

crates/hir/src/semantics/source_to_def.rs

@@ -399,19 +399,6 @@ impl SourceToDefCtx<'_, '_> {
         Some((container, label?))
     }
 
-    pub(super) fn item_to_macro_call(&mut self, src: InFile<&ast::Item>) -> Option<MacroCallId> {
-        let map = self.dyn_map(src)?;
-        map[keys::ATTR_MACRO_CALL].get(&AstPtr::new(src.value)).copied()
-    }
-
-    pub(super) fn macro_call_to_macro_call(
-        &mut self,
-        src: InFile<&ast::MacroCall>,
-    ) -> Option<MacroCallId> {
-        let map = self.dyn_map(src)?;
-        map[keys::MACRO_CALL].get(&AstPtr::new(src.value)).copied()
-    }
-
     /// (AttrId, derive attribute call id, derive call ids)
     pub(super) fn attr_to_derive_macro_call(
         &mut self,
@@ -449,6 +436,17 @@ impl SourceToDefCtx<'_, '_> {
             .or_insert_with(|| container.child_by_source(db, file_id))
     }
 
+    pub(super) fn item_to_macro_call(&mut self, src: InFile<&ast::Item>) -> Option<MacroCallId> {
+        self.to_def(src, keys::ATTR_MACRO_CALL)
+    }
+
+    pub(super) fn macro_call_to_macro_call(
+        &mut self,
+        src: InFile<&ast::MacroCall>,
+    ) -> Option<MacroCallId> {
+        self.to_def(src, keys::MACRO_CALL)
+    }
+
     pub(super) fn type_param_to_def(
         &mut self,
         src: InFile<&ast::TypeParam>,

crates/ide/src/expand_macro.rs

@@ -1,10 +1,10 @@
 use hir::db::ExpandDatabase;
-use hir::{ExpandResult, InFile, Semantics};
+use hir::{ExpandResult, InFile, InRealFile, Semantics};
 use ide_db::{
     FileId, RootDatabase, base_db::Crate, helpers::pick_best_token,
     syntax_helpers::prettify_macro_expansion,
 };
-use span::{Edition, SpanMap, SyntaxContext, TextRange, TextSize};
+use span::{SpanMap, SyntaxContext, TextRange, TextSize};
 use stdx::format_to;
 use syntax::{AstNode, NodeOrToken, SyntaxKind, SyntaxNode, T, ast, ted};
 
@@ -26,8 +26,9 @@ pub struct ExpandedMacro {
 // ![Expand Macro Recursively](https://user-images.githubusercontent.com/48062697/113020648-b3973180-917a-11eb-84a9-ecb921293dc5.gif)
 pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<ExpandedMacro> {
     let sema = Semantics::new(db);
-    let file = sema.parse_guess_edition(position.file_id);
-    let krate = sema.file_to_module_def(position.file_id)?.krate().into();
+    let file_id = sema.attach_first_edition(position.file_id)?;
+    let file = sema.parse(file_id);
+    let krate = sema.file_to_module_def(file_id.file_id(db))?.krate().into();
 
     let tok = pick_best_token(file.syntax().token_at_offset(position.offset), |kind| match kind {
         SyntaxKind::IDENT => 1,
@@ -86,7 +87,10 @@ pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<
         return derive;
     }
 
-    let mut anc = tok.parent_ancestors();
+    let mut anc = sema
+        .descend_token_into_include_expansion(InRealFile::new(file_id, tok))
+        .value
+        .parent_ancestors();
     let mut span_map = SpanMap::empty();
     let mut error = String::new();
     let (name, expanded, kind) = loop {
@@ -95,14 +99,7 @@ pub(crate) fn expand_macro(db: &RootDatabase, position: FilePosition) -> Option<
         if let Some(item) = ast::Item::cast(node.clone()) {
             if let Some(def) = sema.resolve_attr_macro_call(&item) {
                 break (
-                    def.name(db)
-                        .display(
-                            db,
-                            sema.attach_first_edition(position.file_id)
-                                .map(|it| it.edition(db))
-                                .unwrap_or(Edition::CURRENT),
-                        )
-                        .to_string(),
+                    def.name(db).display(db, file_id.edition(db)).to_string(),
                     expand_macro_recur(&sema, &item, &mut error, &mut span_map, TextSize::new(0))?,
                     SyntaxKind::MACRO_ITEMS,
                 );
@@ -759,4 +756,48 @@ fn test() {
                 "<>hi""#]],
         );
     }
+
+    #[test]
+    fn in_included() {
+        check(
+            r#"
+//- minicore: include
+//- /main.rs crate:main
+include!("./included.rs");
+//- /included.rs
+macro_rules! foo {
+    () => { fn item() {} };
+}
+foo$0!();
+"#,
+            expect![[r#"
+                foo!
+                fn item(){}"#]],
+        );
+    }
+
+    #[test]
+    fn include() {
+        check(
+            r#"
+//- minicore: include
+//- /main.rs crate:main
+include$0!("./included.rs");
+//- /included.rs
+macro_rules! foo {
+    () => { fn item() {} };
+}
+foo();
+"#,
+            expect![[r#"
+                include!
+                macro_rules! foo {
+                    () => {
+                        fn item(){}
+
+                    };
+                }
+                foo();"#]],
+        );
+    }
 }