15 files changed, 92 insertions, 31 deletions

diff --git a/crates/ra_ide_api/src/completion/completion_item.rs b/crates/ra_ide_api/src/completion/completion_item.rs
index d70c36889..680fd8d1b 100644
--- a/crates/ra_ide_api/src/completion/completion_item.rs
+++ b/crates/ra_ide_api/src/completion/completion_item.rs
@@ -1,7 +1,10 @@
 use hir::PerNs;
 
 use crate::completion::completion_context::CompletionContext;
-use ra_syntax::TextRange;
+use ra_syntax::{
+    ast::{self, AstNode},
+    TextRange
+};
 use ra_text_edit::TextEdit;
 
 /// `CompletionItem` describes a single completion variant in the editor pop-up.
@@ -263,6 +266,10 @@ impl Builder {
             self.documentation = Some(docs);
         }
 
+        if let Some(label) = function_label(ctx, function) {
+            self.detail = Some(label);
+        }
+
         self.kind = Some(CompletionItemKind::Function);
         self
     }
@@ -299,6 +306,26 @@ impl Into<Vec<CompletionItem>> for Completions {
     }
 }
 
+fn function_label(ctx: &CompletionContext, function: hir::Function) -> Option<String> {
+    let node = function.source(ctx.db).1;
+
+    let label: String = if let Some(body) = node.body() {
+        let body_range = body.syntax().range();
+        let label: String = node
+            .syntax()
+            .children()
+            .filter(|child| !child.range().is_subrange(&body_range)) // Filter out body
+            .filter(|child| ast::Comment::cast(child).is_none()) // Filter out comments
+            .map(|node| node.text().to_string())
+            .collect();
+        label
+    } else {
+        node.syntax().text().to_string()
+    };
+
+    Some(label.trim().to_owned())
+}
+
 #[cfg(test)]
 pub(crate) fn check_completion(test_name: &str, code: &str, kind: CompletionKind) {
     use crate::mock_analysis::{single_file_with_position, analysis_and_position};
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_for.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_for.snap
index 3d8d5af78..eb806ad62 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_for.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_for.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.858540400+00:00"
+created: "2019-01-22T15:38:19.841148300+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -25,7 +25,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn quux()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_if_let.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_if_let.snap
index 7ed1d5ccb..4bb28c7e8 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_if_let.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_if_let.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.860535200+00:00"
+created: "2019-01-22T15:38:19.863089100+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -39,7 +39,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn quux()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_let.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_let.snap
index 95581122d..0579d00ec 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_let.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__bindings_from_let.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.871506600+00:00"
+created: "2019-01-22T15:38:19.881041600+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -39,7 +39,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn quux(x: i32)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_if_already_call.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_if_already_call.snap
index 18d8b3fb3..091bf581e 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_if_already_call.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_if_already_call.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.797704900+00:00"
+created: "2019-01-22T15:38:19.788294+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn main()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: None,
@@ -25,7 +27,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn frobnicate()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: None,
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_in_use_item.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_in_use_item.snap
index 8bf7bf06c..3bc3f5f38 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_in_use_item.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_render_function_parens_in_use_item.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.801693300+00:00"
+created: "2019-01-22T15:38:19.815217100+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "pub fn foo()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: None,
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_show_both_completions_for_shadowing.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_show_both_completions_for_shadowing.snap
index 5844254e1..3e88d8c8e 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_show_both_completions_for_shadowing.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__dont_show_both_completions_for_shadowing.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.912397100+00:00"
+created: "2019-01-22T15:38:19.914951100+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -25,7 +25,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn foo() ->"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls1.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls1.snap
index 732a87382..b30a4c9e9 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls1.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls1.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.932343200+00:00"
+created: "2019-01-22T15:38:19.919937+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn no_args()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -27,7 +29,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn main()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls2.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls2.snap
index 2431b3276..c524f3587 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls2.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__inserts_parens_for_function_calls2.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.995180+00:00"
+created: "2019-01-22T15:38:19.996733+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn main()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -27,7 +29,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn with_args(x: i32, y: String)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__method_completion.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__method_completion.snap
index c294de5cb..ffeac0bf4 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__method_completion.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__method_completion.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.546394900+00:00"
+created: "2019-01-22T15:38:19.541947400+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Method
         ),
-        detail: None,
+        detail: Some(
+            "fn the_method(&self)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items.snap
index 032516ab4..df9677ba3 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.874497400+00:00"
+created: "2019-01-22T15:38:19.896999400+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn quux()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items_in_nested_modules.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items_in_nested_modules.snap
index b33babaf0..f4b38feb0 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items_in_nested_modules.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__module_items_in_nested_modules.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.875495300+00:00"
+created: "2019-01-22T15:38:19.896002200+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -11,7 +11,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn quux()"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__return_type.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__return_type.snap
index 24dbe6bb0..e6819f231 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__return_type.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__return_type.snap
@@ -25,7 +25,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Function
         ),
-        detail: None,
+        detail: Some(
+            "fn x() ->"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_autoderef.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_autoderef.snap
index 9ee668b35..5ef140b28 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_autoderef.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_autoderef.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.552379600+00:00"
+created: "2019-01-22T15:38:19.541947400+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -27,7 +27,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Method
         ),
-        detail: None,
+        detail: Some(
+            "fn foo(&self)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_self.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_self.snap
index b9d70ea3f..b7903c5bc 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_self.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__struct_field_completion_self.snap
@@ -1,5 +1,5 @@
 ---
-created: "2019-01-22T14:45:00.552379600+00:00"
+created: "2019-01-22T15:38:19.541947400+00:00"
 creator: [email protected]
 expression: kind_completions
 source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
@@ -27,7 +27,9 @@ source: "crates\\ra_ide_api\\src\\completion\\completion_item.rs"
         kind: Some(
             Method
         ),
-        detail: None,
+        detail: Some(
+            "fn foo(self)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(