7 files changed, 120 insertions, 32 deletions

diff --git a/crates/ra_analysis/src/completion/complete_keyword.rs b/crates/ra_analysis/src/completion/complete_keyword.rs
index d1e0a20a8..2869e67e0 100644
--- a/crates/ra_analysis/src/completion/complete_keyword.rs
+++ b/crates/ra_analysis/src/completion/complete_keyword.rs
@@ -35,7 +35,7 @@ pub(super) fn complete_expr_keyword(acc: &mut Completions, ctx: &CompletionConte
         acc.add(keyword("continue", "continue"));
         acc.add(keyword("break", "break"));
     }
-    acc.add_all(complete_return(fn_def, ctx.is_stmt));
+    acc.add_all(complete_return(fn_def, ctx.can_be_stmt));
 }
 
 fn is_in_loop_body(leaf: SyntaxNodeRef) -> bool {
@@ -57,8 +57,8 @@ fn is_in_loop_body(leaf: SyntaxNodeRef) -> bool {
     false
 }
 
-fn complete_return(fn_def: ast::FnDef, is_stmt: bool) -> Option<CompletionItem> {
-    let snip = match (is_stmt, fn_def.ret_type().is_some()) {
+fn complete_return(fn_def: ast::FnDef, can_be_stmt: bool) -> Option<CompletionItem> {
+    let snip = match (can_be_stmt, fn_def.ret_type().is_some()) {
         (true, true) => "return $0;",
         (true, false) => "return;",
         (false, true) => "return $0",
@@ -75,7 +75,7 @@ mod tests {
     }
 
     #[test]
-    fn test_completion_kewords() {
+    fn completes_various_keywords_in_function() {
         check_keyword_completion(
             r"
             fn quux() {
@@ -87,13 +87,13 @@ mod tests {
             match "match $0 {}"
             while "while $0 {}"
             loop "loop {$0}"
-            return "return"
+            return "return;"
             "#,
         );
     }
 
     #[test]
-    fn test_completion_else() {
+    fn completes_else_after_if() {
         check_keyword_completion(
             r"
             fn quux() {
@@ -109,7 +109,7 @@ mod tests {
             loop "loop {$0}"
             else "else {$0}"
             else if "else if $0 {}"
-            return "return"
+            return "return;"
             "#,
         );
     }
@@ -149,7 +149,7 @@ mod tests {
     }
 
     #[test]
-    fn test_completion_return_no_stmt() {
+    fn dont_add_semi_after_return_if_not_a_statement() {
         check_keyword_completion(
             r"
             fn quux() -> i32 {
@@ -169,7 +169,27 @@ mod tests {
     }
 
     #[test]
-    fn test_continue_break_completion() {
+    fn last_return_in_block_has_semi() {
+        check_keyword_completion(
+            r"
+            fn quux() -> i32 {
+                if condition {
+                    <|>
+                }
+            }
+            ",
+            r#"
+            if "if $0 {}"
+            match "match $0 {}"
+            while "while $0 {}"
+            loop "loop {$0}"
+            return "return $0;"
+            "#,
+        );
+    }
+
+    #[test]
+    fn completes_break_and_continue_in_loops() {
         check_keyword_completion(
             r"
             fn quux() -> i32 {
@@ -183,9 +203,10 @@ mod tests {
             loop "loop {$0}"
             continue "continue"
             break "break"
-            return "return $0"
+            return "return $0;"
             "#,
         );
+        // No completion: lambda isolates control flow
         check_keyword_completion(
             r"
             fn quux() -> i32 {
@@ -197,7 +218,7 @@ mod tests {
             match "match $0 {}"
             while "while $0 {}"
             loop "loop {$0}"
-            return "return $0"
+            return "return $0;"
             "#,
         );
     }
diff --git a/crates/ra_analysis/src/completion/complete_path.rs b/crates/ra_analysis/src/completion/complete_path.rs
index c73a083a4..4723a65a6 100644
--- a/crates/ra_analysis/src/completion/complete_path.rs
+++ b/crates/ra_analysis/src/completion/complete_path.rs
@@ -17,7 +17,7 @@ pub(super) fn complete_path(acc: &mut Completions, ctx: &CompletionContext) -> C
             let module_scope = module.scope(ctx.db)?;
             module_scope.entries().for_each(|(name, res)| {
                 CompletionItem::new(CompletionKind::Reference, name.to_string())
-                    .from_resolution(ctx.db, res)
+                    .from_resolution(ctx, res)
                     .add_to(acc)
             });
         }
@@ -113,4 +113,16 @@ mod tests {
             "Foo;Bar",
         );
     }
+
+    #[test]
+    fn dont_render_function_parens_in_use_item() {
+        check_reference_completion(
+            "
+            //- /lib.rs
+            mod m { pub fn foo() {} }
+            use crate::m::f<|>;
+            ",
+            "foo",
+        )
+    }
 }
diff --git a/crates/ra_analysis/src/completion/complete_scope.rs b/crates/ra_analysis/src/completion/complete_scope.rs
index 514fd2f88..daf666505 100644
--- a/crates/ra_analysis/src/completion/complete_scope.rs
+++ b/crates/ra_analysis/src/completion/complete_scope.rs
@@ -34,7 +34,7 @@ pub(super) fn complete_scope(acc: &mut Completions, ctx: &CompletionContext) ->
         })
         .for_each(|(name, res)| {
             CompletionItem::new(CompletionKind::Reference, name.to_string())
-                .from_resolution(ctx.db, res)
+                .from_resolution(ctx, res)
                 .add_to(acc)
         });
     Ok(())
@@ -74,7 +74,7 @@ mod tests {
                 let z = ();
             }
             ",
-            "y;x;quux",
+            r#"y;x;quux "quux($0)""#,
         );
     }
 
@@ -92,7 +92,7 @@ mod tests {
                 }
             }
             ",
-            "b;a;quux",
+            r#"b;a;quux "quux()$0""#,
         );
     }
 
@@ -106,7 +106,7 @@ mod tests {
                 }
             }
             ",
-            "x;quux",
+            r#"x;quux "quux()$0""#,
         );
     }
 
@@ -120,7 +120,7 @@ mod tests {
                 <|>
             }
             ",
-            "quux;Foo;Baz",
+            r#"quux "quux()$0";Foo;Baz"#,
         );
     }
 
@@ -134,7 +134,7 @@ mod tests {
                 fn quux() { <|> }
             }
             ",
-            "quux;Bar",
+            r#"quux "quux()$0";Bar"#,
         );
     }
 
@@ -145,12 +145,12 @@ mod tests {
             struct Foo;
             fn x() -> <|>
             ",
-            "Foo;x",
+            r#"Foo;x "x()$0""#,
         )
     }
 
     #[test]
-    fn dont_show_to_completions_for_shadowing() {
+    fn dont_show_both_completions_for_shadowing() {
         check_reference_completion(
             r"
             fn foo() -> {
@@ -161,7 +161,7 @@ mod tests {
                 }
             }
             ",
-            "bar;foo",
+            r#"bar;foo "foo()$0""#,
         )
     }
 
@@ -169,4 +169,24 @@ mod tests {
     fn completes_self_in_methods() {
         check_reference_completion(r"impl S { fn foo(&self) { <|> } }", "self")
     }
+
+    #[test]
+    fn inserts_parens_for_function_calls() {
+        check_reference_completion(
+            r"
+            fn no_args() {}
+            fn main() { no_<|> }
+            ",
+            r#"no_args "no_args()$0"
+               main "main()$0""#,
+        );
+        check_reference_completion(
+            r"
+            fn with_args(x: i32, y: String) {}
+            fn main() { with_<|> }
+            ",
+            r#"main "main()$0"
+               with_args "with_args($0)""#,
+        );
+    }
 }
diff --git a/crates/ra_analysis/src/completion/completion_context.rs b/crates/ra_analysis/src/completion/completion_context.rs
index 71bf7fd32..4685c9328 100644
--- a/crates/ra_analysis/src/completion/completion_context.rs
+++ b/crates/ra_analysis/src/completion/completion_context.rs
@@ -24,13 +24,15 @@ pub(super) struct CompletionContext<'a> {
     pub(super) module: Option<hir::Module>,
     pub(super) function: Option<hir::Function>,
     pub(super) function_syntax: Option<ast::FnDef<'a>>,
+    pub(super) use_item_syntax: Option<ast::UseItem<'a>>,
     pub(super) is_param: bool,
     /// A single-indent path, like `foo`.
     pub(super) is_trivial_path: bool,
     /// If not a trivial, path, the prefix (qualifier).
     pub(super) path_prefix: Option<hir::Path>,
     pub(super) after_if: bool,
-    pub(super) is_stmt: bool,
+    /// `true` if we are a statement or a last expr in the block.
+    pub(super) can_be_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.<|>
@@ -55,11 +57,12 @@ impl<'a> CompletionContext<'a> {
             module,
             function: None,
             function_syntax: None,
+            use_item_syntax: None,
             is_param: false,
             is_trivial_path: false,
             path_prefix: None,
             after_if: false,
-            is_stmt: false,
+            can_be_stmt: false,
             is_new_item: false,
             dot_receiver: None,
             is_method_call: false,
@@ -114,6 +117,8 @@ impl<'a> CompletionContext<'a> {
             _ => (),
         }
 
+        self.use_item_syntax = self.leaf.ancestors().find_map(ast::UseItem::cast);
+
         self.function_syntax = self
             .leaf
             .ancestors()
@@ -143,13 +148,22 @@ impl<'a> CompletionContext<'a> {
             if path.qualifier().is_none() {
                 self.is_trivial_path = true;
 
-                self.is_stmt = match name_ref
+                self.can_be_stmt = match name_ref
                     .syntax()
                     .ancestors()
                     .filter_map(ast::ExprStmt::cast)
                     .next()
                 {
-                    None => false,
+                    None => {
+                        name_ref
+                            .syntax()
+                            .ancestors()
+                            .filter_map(ast::Block::cast)
+                            .next()
+                            .and_then(|block| block.expr())
+                            .map(|e| e.syntax().range())
+                            == Some(name_ref.syntax().range())
+                    }
                     Some(expr_stmt) => expr_stmt.syntax().range() == name_ref.syntax().range(),
                 };
 
diff --git a/crates/ra_analysis/src/completion/completion_item.rs b/crates/ra_analysis/src/completion/completion_item.rs
index 1d294c553..cd4d529f9 100644
--- a/crates/ra_analysis/src/completion/completion_item.rs
+++ b/crates/ra_analysis/src/completion/completion_item.rs
@@ -1,7 +1,7 @@
-use crate::db;
-
 use hir::PerNs;
 
+use crate::completion::CompletionContext;
+
 /// `CompletionItem` describes a single completion variant in the editor pop-up.
 /// It is basically a POD with various properties. To construct a
 /// `CompletionItem`, use `new` method and the `Builder` struct.
@@ -118,12 +118,12 @@ impl Builder {
         self.kind = Some(kind);
         self
     }
-    pub(crate) fn from_resolution(
+    pub(super) fn from_resolution(
         mut self,
-        db: &db::RootDatabase,
+        ctx: &CompletionContext,
         resolution: &hir::Resolution,
     ) -> Builder {
-        let resolved = resolution.def_id.and_then(|d| d.resolve(db).ok());
+        let resolved = resolution.def_id.and_then(|d| d.resolve(ctx.db).ok());
         let kind = match resolved {
             PerNs {
                 types: Some(hir::Def::Module(..)),
@@ -138,14 +138,29 @@ impl Builder {
                 ..
             } => CompletionItemKind::Enum,
             PerNs {
-                values: Some(hir::Def::Function(..)),
+                values: Some(hir::Def::Function(function)),
                 ..
-            } => CompletionItemKind::Function,
+            } => return self.from_function(ctx, function),
             _ => return self,
         };
         self.kind = Some(kind);
         self
     }
+
+    fn from_function(mut self, ctx: &CompletionContext, function: hir::Function) -> Builder {
+        // If not an import, add parenthesis automatically.
+        if ctx.use_item_syntax.is_none() {
+            if let Some(sig_info) = function.signature_info(ctx.db) {
+                if sig_info.params.is_empty() {
+                    self.snippet = Some(format!("{}()$0", self.label));
+                } else {
+                    self.snippet = Some(format!("{}($0)", self.label));
+                }
+            }
+        }
+        self.kind = Some(CompletionItemKind::Function);
+        self
+    }
 }
 
 impl Into<CompletionItem> for Builder {
diff --git a/crates/ra_analysis/src/imp.rs b/crates/ra_analysis/src/imp.rs
index fcb4cd957..bff2e00c9 100644
--- a/crates/ra_analysis/src/imp.rs
+++ b/crates/ra_analysis/src/imp.rs
@@ -140,6 +140,9 @@ impl fmt::Debug for AnalysisImpl {
 }
 
 impl AnalysisImpl {
+    pub fn file_text(&self, file_id: FileId) -> Arc<String> {
+        self.db.file_text(file_id)
+    }
     pub fn file_syntax(&self, file_id: FileId) -> SourceFileNode {
         self.db.source_file(file_id)
     }
diff --git a/crates/ra_analysis/src/lib.rs b/crates/ra_analysis/src/lib.rs
index 67b1c1482..9f5e9f358 100644
--- a/crates/ra_analysis/src/lib.rs
+++ b/crates/ra_analysis/src/lib.rs
@@ -274,6 +274,9 @@ pub struct Analysis {
 }
 
 impl Analysis {
+    pub fn file_text(&self, file_id: FileId) -> Arc<String> {
+        self.imp.file_text(file_id)
+    }
     pub fn file_syntax(&self, file_id: FileId) -> SourceFileNode {
         self.imp.file_syntax(file_id).clone()
     }