3 files changed, 87 insertions, 2 deletions

diff --git a/crates/ra_hir/Cargo.toml b/crates/ra_hir/Cargo.toml
index 0555a0de7..266c4cff3 100644
--- a/crates/ra_hir/Cargo.toml
+++ b/crates/ra_hir/Cargo.toml
@@ -12,6 +12,8 @@ log = "0.4.8"
 rustc-hash = "1.1.0"
 either = "1.5.3"
 
+itertools = "0.8.2"
+
 ra_syntax = { path = "../ra_syntax" }
 ra_db = { path = "../ra_db" }
 ra_prof = { path = "../ra_prof" }
diff --git a/crates/ra_hir/src/code_model.rs b/crates/ra_hir/src/code_model.rs
index 9685d6982..78c444037 100644
--- a/crates/ra_hir/src/code_model.rs
+++ b/crates/ra_hir/src/code_model.rs
@@ -207,10 +207,26 @@ impl Module {
     }
 
     /// Returns a `ModuleScope`: a set of items, visible in this module.
-    pub fn scope(self, db: &impl HirDatabase) -> Vec<(Name, ScopeDef)> {
+    pub fn scope(
+        self,
+        db: &impl HirDatabase,
+        visible_from: Option<Module>,
+    ) -> Vec<(Name, ScopeDef)> {
         db.crate_def_map(self.id.krate)[self.id.local_id]
             .scope
             .entries()
+            .filter_map(|(name, def)| {
+                if let Some(m) = visible_from {
+                    let filtered = def.filter_visibility(|vis| vis.is_visible_from(db, m.id));
+                    if filtered.is_none() && !def.is_none() {
+                        None
+                    } else {
+                        Some((name, filtered))
+                    }
+                } else {
+                    Some((name, def))
+                }
+            })
             .map(|(name, def)| (name.clone(), def.into()))
             .collect()
     }
@@ -598,6 +614,14 @@ impl Function {
     }
 }
 
+impl HasVisibility for Function {
+    fn visibility(&self, db: &impl HirDatabase) -> Visibility {
+        let function_data = db.function_data(self.id);
+        let visibility = &function_data.visibility;
+        visibility.resolve(db, &self.id.resolver(db))
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Const {
     pub(crate) id: ConstId,
@@ -617,6 +641,14 @@ impl Const {
     }
 }
 
+impl HasVisibility for Const {
+    fn visibility(&self, db: &impl HirDatabase) -> Visibility {
+        let function_data = db.const_data(self.id);
+        let visibility = &function_data.visibility;
+        visibility.resolve(db, &self.id.resolver(db))
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct Static {
     pub(crate) id: StaticId,
@@ -691,6 +723,14 @@ impl TypeAlias {
     }
 }
 
+impl HasVisibility for TypeAlias {
+    fn visibility(&self, db: &impl HirDatabase) -> Visibility {
+        let function_data = db.type_alias_data(self.id);
+        let visibility = &function_data.visibility;
+        visibility.resolve(db, &self.id.resolver(db))
+    }
+}
+
 #[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)]
 pub struct MacroDef {
     pub(crate) id: MacroDefId,
@@ -778,6 +818,16 @@ impl AssocItem {
     }
 }
 
+impl HasVisibility for AssocItem {
+    fn visibility(&self, db: &impl HirDatabase) -> Visibility {
+        match self {
+            AssocItem::Function(f) => f.visibility(db),
+            AssocItem::Const(c) => c.visibility(db),
+            AssocItem::TypeAlias(t) => t.visibility(db),
+        }
+    }
+}
+
 #[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
 pub enum GenericDef {
     Function(Function),
diff --git a/crates/ra_hir/src/semantics.rs b/crates/ra_hir/src/semantics.rs
index 965d185a4..3782a9984 100644
--- a/crates/ra_hir/src/semantics.rs
+++ b/crates/ra_hir/src/semantics.rs
@@ -6,7 +6,7 @@ use std::{cell::RefCell, fmt, iter::successors};
 
 use hir_def::{
     resolver::{self, HasResolver, Resolver},
-    TraitId,
+    AsMacroCall, TraitId,
 };
 use hir_expand::ExpansionInfo;
 use ra_db::{FileId, FileRange};
@@ -70,6 +70,20 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         Some(node)
     }
 
+    pub fn expand_hypothetical(
+        &self,
+        actual_macro_call: &ast::MacroCall,
+        hypothetical_args: &ast::TokenTree,
+        token_to_map: SyntaxToken,
+    ) -> Option<(SyntaxNode, SyntaxToken)> {
+        let macro_call =
+            self.find_file(actual_macro_call.syntax().clone()).with_value(actual_macro_call);
+        let sa = self.analyze2(macro_call.map(|it| it.syntax()), None);
+        let macro_call_id = macro_call
+            .as_call_id(self.db, |path| sa.resolver.resolve_path_as_macro(self.db, &path))?;
+        hir_expand::db::expand_hypothetical(self.db, macro_call_id, hypothetical_args, token_to_map)
+    }
+
     pub fn descend_into_macros(&self, token: SyntaxToken) -> SyntaxToken {
         let parent = token.parent();
         let parent = self.find_file(parent);
@@ -104,6 +118,25 @@ impl<'db, DB: HirDatabase> Semantics<'db, DB> {
         node.ancestors_with_macros(self.db).map(|it| it.value)
     }
 
+    pub fn ancestors_at_offset_with_macros(
+        &self,
+        node: &SyntaxNode,
+        offset: TextUnit,
+    ) -> impl Iterator<Item = SyntaxNode> + '_ {
+        use itertools::Itertools;
+        node.token_at_offset(offset)
+            .map(|token| self.ancestors_with_macros(token.parent()))
+            .kmerge_by(|node1, node2| node1.text_range().len() < node2.text_range().len())
+    }
+
+    pub fn find_node_at_offset_with_macros<N: AstNode>(
+        &self,
+        node: &SyntaxNode,
+        offset: TextUnit,
+    ) -> Option<N> {
+        self.ancestors_at_offset_with_macros(node, offset).find_map(N::cast)
+    }
+
     pub fn type_of_expr(&self, expr: &ast::Expr) -> Option<Type> {
         self.analyze(expr.syntax()).type_of(self.db, &expr)
     }