1 files changed, 44 insertions, 10 deletions

diff --git a/crates/ra_analysis/src/completion/completion_context.rs b/crates/ra_analysis/src/completion/completion_context.rs
index 064fbc6f7..978772fd4 100644
--- a/crates/ra_analysis/src/completion/completion_context.rs
+++ b/crates/ra_analysis/src/completion/completion_context.rs
@@ -1,12 +1,13 @@
 use ra_editor::find_node_at_offset;
 use ra_text_edit::AtomTextEdit;
 use ra_syntax::{
-    algo::find_leaf_at_offset,
+    algo::{find_leaf_at_offset, find_covering_node},
     ast,
     AstNode,
     SyntaxNodeRef,
     SourceFileNode,
     TextUnit,
+    TextRange,
     SyntaxKind::*,
 };
 use hir::source_binder;
@@ -31,6 +32,10 @@ pub(super) struct CompletionContext<'a> {
     pub(super) is_stmt: bool,
     /// Something is typed at the "top" level, in module or impl/trait.
     pub(super) is_new_item: bool,
+    /// The receiver if this is a field or method access, i.e. writing something.<|>
+    pub(super) dot_receiver: Option<ast::Expr<'a>>,
+    /// If this is a method call in particular, i.e. the () are already there.
+    pub(super) is_method_call: bool,
 }
 
 impl<'a> CompletionContext<'a> {
@@ -54,12 +59,14 @@ impl<'a> CompletionContext<'a> {
             after_if: false,
             is_stmt: false,
             is_new_item: false,
+            dot_receiver: None,
+            is_method_call: false,
         };
         ctx.fill(original_file, position.offset);
         Ok(Some(ctx))
     }
 
-    fn fill(&mut self, original_file: &SourceFileNode, offset: TextUnit) {
+    fn fill(&mut self, original_file: &'a SourceFileNode, offset: TextUnit) {
         // Insert a fake ident to get a valid parse tree. We will use this file
         // to determine context, though the original_file will be used for
         // actual completion.
@@ -76,7 +83,7 @@ impl<'a> CompletionContext<'a> {
                 self.is_param = true;
                 return;
             }
-            self.classify_name_ref(&file, name_ref);
+            self.classify_name_ref(original_file, name_ref);
         }
 
         // Otherwise, see if this is a declaration. We can use heuristics to
@@ -88,7 +95,7 @@ impl<'a> CompletionContext<'a> {
             }
         }
     }
-    fn classify_name_ref(&mut self, file: &SourceFileNode, name_ref: ast::NameRef) {
+    fn classify_name_ref(&mut self, original_file: &'a SourceFileNode, name_ref: ast::NameRef) {
         let name_range = name_ref.syntax().range();
         let top_node = name_ref
             .syntax()
@@ -105,6 +112,12 @@ impl<'a> CompletionContext<'a> {
             _ => (),
         }
 
+        self.enclosing_fn = self
+            .leaf
+            .ancestors()
+            .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
+            .find_map(ast::FnDef::cast);
+
         let parent = match name_ref.syntax().parent() {
             Some(it) => it,
             None => return,
@@ -120,11 +133,6 @@ impl<'a> CompletionContext<'a> {
             }
             if path.qualifier().is_none() {
                 self.is_trivial_path = true;
-                self.enclosing_fn = self
-                    .leaf
-                    .ancestors()
-                    .take_while(|it| it.kind() != SOURCE_FILE && it.kind() != MODULE)
-                    .find_map(ast::FnDef::cast);
 
                 self.is_stmt = match name_ref
                     .syntax()
@@ -137,7 +145,9 @@ impl<'a> CompletionContext<'a> {
                 };
 
                 if let Some(off) = name_ref.syntax().range().start().checked_sub(2.into()) {
-                    if let Some(if_expr) = find_node_at_offset::<ast::IfExpr>(file.syntax(), off) {
+                    if let Some(if_expr) =
+                        find_node_at_offset::<ast::IfExpr>(original_file.syntax(), off)
+                    {
                         if if_expr.syntax().range().end() < name_ref.syntax().range().start() {
                             self.after_if = true;
                         }
@@ -145,9 +155,33 @@ impl<'a> CompletionContext<'a> {
                 }
             }
         }
+        if let Some(field_expr) = ast::FieldExpr::cast(parent) {
+            // The receiver comes before the point of insertion of the fake
+            // ident, so it should have the same range in the non-modified file
+            self.dot_receiver = field_expr
+                .expr()
+                .map(|e| e.syntax().range())
+                .and_then(|r| find_node_with_range(original_file.syntax(), r));
+        }
+        if let Some(method_call_expr) = ast::MethodCallExpr::cast(parent) {
+            // As above
+            self.dot_receiver = method_call_expr
+                .expr()
+                .map(|e| e.syntax().range())
+                .and_then(|r| find_node_with_range(original_file.syntax(), r));
+            self.is_method_call = true;
+        }
     }
 }
 
+fn find_node_with_range<'a, N: AstNode<'a>>(
+    syntax: SyntaxNodeRef<'a>,
+    range: TextRange,
+) -> Option<N> {
+    let node = find_covering_node(syntax, range);
+    node.ancestors().find_map(N::cast)
+}
+
 fn is_node<'a, N: AstNode<'a>>(node: SyntaxNodeRef<'a>) -> bool {
     match node.ancestors().filter_map(N::cast).next() {
         None => false,