8 files changed, 49 insertions, 30 deletions

diff --git a/crates/ra_assists/src/assist_ctx.rs b/crates/ra_assists/src/assist_ctx.rs
index 1908bdec9..71f7ce1b1 100644
--- a/crates/ra_assists/src/assist_ctx.rs
+++ b/crates/ra_assists/src/assist_ctx.rs
@@ -1,6 +1,5 @@
 //! This module defines `AssistCtx` -- the API surface that is exposed to assists.
-
-use hir::db::HirDatabase;
+use hir::{db::HirDatabase, SourceAnalyzer};
 use ra_db::FileRange;
 use ra_fmt::{leading_indent, reindent};
 use ra_syntax::{
@@ -113,6 +112,13 @@ impl<'a, DB: HirDatabase> AssistCtx<'a, DB> {
     pub(crate) fn covering_element(&self) -> SyntaxElement {
         find_covering_element(self.source_file.syntax(), self.frange.range)
     }
+    pub(crate) fn source_analyzer(
+        &self,
+        node: &SyntaxNode,
+        offset: Option<TextUnit>,
+    ) -> SourceAnalyzer {
+        SourceAnalyzer::new(self.db, self.frange.file_id, node, offset)
+    }
 
     pub(crate) fn covering_node_for_range(&self, range: TextRange) -> SyntaxElement {
         find_covering_element(self.source_file.syntax(), range)
diff --git a/crates/ra_assists/src/assists/add_explicit_type.rs b/crates/ra_assists/src/assists/add_explicit_type.rs
index ddda1a0f2..562a09685 100644
--- a/crates/ra_assists/src/assists/add_explicit_type.rs
+++ b/crates/ra_assists/src/assists/add_explicit_type.rs
@@ -40,7 +40,7 @@ pub(crate) fn add_explicit_type(ctx: AssistCtx<impl HirDatabase>) -> Option<Assi
     }
     // Infer type
     let db = ctx.db;
-    let analyzer = hir::SourceAnalyzer::new(db, ctx.frange.file_id, stmt.syntax(), None);
+    let analyzer = ctx.source_analyzer(stmt.syntax(), None);
     let ty = analyzer.type_of(db, &expr)?;
     // Assist not applicable if the type is unknown
     if is_unknown(&ty) {
diff --git a/crates/ra_assists/src/assists/add_missing_impl_members.rs b/crates/ra_assists/src/assists/add_missing_impl_members.rs
index 41de23921..91af161ee 100644
--- a/crates/ra_assists/src/assists/add_missing_impl_members.rs
+++ b/crates/ra_assists/src/assists/add_missing_impl_members.rs
@@ -100,8 +100,7 @@ fn add_missing_impl_members_inner(
     let impl_item_list = impl_node.item_list()?;
 
     let trait_def = {
-        let file_id = ctx.frange.file_id;
-        let analyzer = hir::SourceAnalyzer::new(ctx.db, file_id, impl_node.syntax(), None);
+        let analyzer = ctx.source_analyzer(impl_node.syntax(), None);
 
         resolve_target_trait_def(ctx.db, &analyzer, &impl_node)?
     };
diff --git a/crates/ra_assists/src/assists/fill_match_arms.rs b/crates/ra_assists/src/assists/fill_match_arms.rs
index 2b74f355c..b851c2082 100644
--- a/crates/ra_assists/src/assists/fill_match_arms.rs
+++ b/crates/ra_assists/src/assists/fill_match_arms.rs
@@ -47,8 +47,7 @@ pub(crate) fn fill_match_arms(ctx: AssistCtx<impl HirDatabase>) -> Option<Assist
 
     let expr = match_expr.expr()?;
     let enum_def = {
-        let file_id = ctx.frange.file_id;
-        let analyzer = hir::SourceAnalyzer::new(ctx.db, file_id, expr.syntax(), None);
+        let analyzer = ctx.source_analyzer(expr.syntax(), None);
         resolve_enum_def(ctx.db, &analyzer, &expr)?
     };
     let variant_list = enum_def.variant_list()?;
diff --git a/crates/ra_assists/src/assists/inline_local_variable.rs b/crates/ra_assists/src/assists/inline_local_variable.rs
index a7fd9b6d2..18a34502c 100644
--- a/crates/ra_assists/src/assists/inline_local_variable.rs
+++ b/crates/ra_assists/src/assists/inline_local_variable.rs
@@ -45,7 +45,7 @@ pub(crate) fn inline_local_varialbe(ctx: AssistCtx<impl HirDatabase>) -> Option<
     } else {
         let_stmt.syntax().text_range()
     };
-    let analyzer = hir::SourceAnalyzer::new(ctx.db, ctx.frange.file_id, bind_pat.syntax(), None);
+    let analyzer = ctx.source_analyzer(bind_pat.syntax(), None);
     let refs = analyzer.find_all_refs(&bind_pat);
 
     let mut wrap_in_parens = vec![true; refs.len()];
diff --git a/crates/ra_hir/src/source_binder.rs b/crates/ra_hir/src/source_binder.rs
index f08827ed3..540ddd0b5 100644
--- a/crates/ra_hir/src/source_binder.rs
+++ b/crates/ra_hir/src/source_binder.rs
@@ -91,7 +91,7 @@ fn def_with_body_from_child_node(
 #[derive(Debug)]
 pub struct SourceAnalyzer {
     // FIXME: this doesn't handle macros at all
-    file_id: FileId,
+    file_id: HirFileId,
     resolver: Resolver,
     body_owner: Option<DefWithBody>,
     body_source_map: Option<Arc<BodySourceMap>>,
@@ -141,13 +141,16 @@ impl SourceAnalyzer {
         node: &SyntaxNode,
         offset: Option<TextUnit>,
     ) -> SourceAnalyzer {
-        let def_with_body = def_with_body_from_child_node(db, Source::new(file_id.into(), node));
+        let node_source = Source::new(file_id.into(), node);
+        let def_with_body = def_with_body_from_child_node(db, node_source);
         if let Some(def) = def_with_body {
             let source_map = def.body_source_map(db);
             let scopes = def.expr_scopes(db);
             let scope = match offset {
-                None => scope_for(&scopes, &source_map, file_id.into(), &node),
-                Some(offset) => scope_for_offset(&scopes, &source_map, file_id.into(), offset),
+                None => scope_for(&scopes, &source_map, node_source),
+                Some(offset) => {
+                    scope_for_offset(&scopes, &source_map, Source::new(file_id.into(), offset))
+                }
             };
             let resolver = expr::resolver_for_scope(db, def, scope);
             SourceAnalyzer {
@@ -156,7 +159,7 @@ impl SourceAnalyzer {
                 body_source_map: Some(source_map),
                 infer: Some(def.infer(db)),
                 scopes: Some(scopes),
-                file_id,
+                file_id: file_id.into(),
             }
         } else {
             SourceAnalyzer {
@@ -168,18 +171,18 @@ impl SourceAnalyzer {
                 body_source_map: None,
                 infer: None,
                 scopes: None,
-                file_id,
+                file_id: file_id.into(),
             }
         }
     }
 
     fn expr_id(&self, expr: &ast::Expr) -> Option<ExprId> {
-        let src = Source { file_id: self.file_id.into(), ast: expr };
+        let src = Source { file_id: self.file_id, ast: expr };
         self.body_source_map.as_ref()?.node_expr(src)
     }
 
     fn pat_id(&self, pat: &ast::Pat) -> Option<PatId> {
-        let src = Source { file_id: self.file_id.into(), ast: pat };
+        let src = Source { file_id: self.file_id, ast: pat };
         self.body_source_map.as_ref()?.node_pat(src)
     }
 
@@ -287,7 +290,7 @@ impl SourceAnalyzer {
         let name = name_ref.as_name();
         let source_map = self.body_source_map.as_ref()?;
         let scopes = self.scopes.as_ref()?;
-        let scope = scope_for(scopes, source_map, self.file_id.into(), name_ref.syntax())?;
+        let scope = scope_for(scopes, source_map, Source::new(self.file_id, name_ref.syntax()))?;
         let entry = scopes.resolve_name_in_scope(scope, &name)?;
         Some(ScopeEntryWithSyntax {
             name: entry.name().clone(),
@@ -408,20 +411,19 @@ impl SourceAnalyzer {
 fn scope_for(
     scopes: &ExprScopes,
     source_map: &BodySourceMap,
-    file_id: HirFileId,
-    node: &SyntaxNode,
+    node: Source<&SyntaxNode>,
 ) -> Option<ScopeId> {
-    node.ancestors()
+    node.ast
+        .ancestors()
         .filter_map(ast::Expr::cast)
-        .filter_map(|it| source_map.node_expr(Source { file_id, ast: &it }))
+        .filter_map(|it| source_map.node_expr(Source::new(node.file_id, &it)))
         .find_map(|it| scopes.scope_for(it))
 }
 
 fn scope_for_offset(
     scopes: &ExprScopes,
     source_map: &BodySourceMap,
-    file_id: HirFileId,
-    offset: TextUnit,
+    offset: Source<TextUnit>,
 ) -> Option<ScopeId> {
     scopes
         .scope_by_expr()
@@ -429,7 +431,7 @@ fn scope_for_offset(
         .filter_map(|(id, scope)| {
             let source = source_map.expr_syntax(*id)?;
             // FIXME: correctly handle macro expansion
-            if source.file_id != file_id {
+            if source.file_id != offset.file_id {
                 return None;
             }
             let syntax_node_ptr =
@@ -438,9 +440,14 @@ fn scope_for_offset(
         })
         // find containing scope
         .min_by_key(|(ptr, _scope)| {
-            (!(ptr.range().start() <= offset && offset <= ptr.range().end()), ptr.range().len())
+            (
+                !(ptr.range().start() <= offset.ast && offset.ast <= ptr.range().end()),
+                ptr.range().len(),
+            )
+        })
+        .map(|(ptr, scope)| {
+            adjust(scopes, source_map, ptr, offset.file_id, offset.ast).unwrap_or(*scope)
         })
-        .map(|(ptr, scope)| adjust(scopes, source_map, ptr, file_id, offset).unwrap_or(*scope))
 }
 
 // XXX: during completion, cursor might be outside of any particular
diff --git a/crates/ra_hir_def/src/nameres.rs b/crates/ra_hir_def/src/nameres.rs
index 49e33ccc4..e5b073a0f 100644
--- a/crates/ra_hir_def/src/nameres.rs
+++ b/crates/ra_hir_def/src/nameres.rs
@@ -125,12 +125,12 @@ pub struct ModuleData {
     pub impls: Vec<ImplId>,
 }
 
-#[derive(Default, Debug, PartialEq, Eq, Clone)]
+#[derive(Default, Debug, PartialEq, Eq)]
 pub(crate) struct Declarations {
     fns: FxHashMap<FileAstId<ast::FnDef>, FunctionId>,
 }
 
-#[derive(Debug, Default, PartialEq, Eq, Clone)]
+#[derive(Debug, Default, PartialEq, Eq)]
 pub struct ModuleScope {
     items: FxHashMap<Name, Resolution>,
     /// Macros visable in current module in legacy textual scope
diff --git a/crates/ra_hir_expand/src/lib.rs b/crates/ra_hir_expand/src/lib.rs
index 437d73e94..26531cb05 100644
--- a/crates/ra_hir_expand/src/lib.rs
+++ b/crates/ra_hir_expand/src/lib.rs
@@ -223,9 +223,12 @@ impl<N: AstNode> AstId<N> {
     }
 }
 
+/// FIXME: https://github.com/matklad/with ?
 #[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
 pub struct Source<T> {
     pub file_id: HirFileId,
+    // FIXME: this stores all kind of things, not only `ast`.
+    // There should be a better name...
     pub ast: T,
 }
 
@@ -234,11 +237,16 @@ impl<T> Source<T> {
         Source { file_id, ast }
     }
 
+    // Similarly, naming here is stupid...
+    pub fn with_ast<U>(&self, ast: U) -> Source<U> {
+        Source::new(self.file_id, ast)
+    }
+
     pub fn map<F: FnOnce(T) -> U, U>(self, f: F) -> Source<U> {
-        Source { file_id: self.file_id, ast: f(self.ast) }
+        Source::new(self.file_id, f(self.ast))
     }
     pub fn as_ref(&self) -> Source<&T> {
-        Source { file_id: self.file_id, ast: &self.ast }
+        self.with_ast(&self.ast)
     }
     pub fn file_syntax(&self, db: &impl db::AstDatabase) -> SyntaxNode {
         db.parse_or_expand(self.file_id).expect("source created from invalid file")