Merge #1110

1110: Introduce display module and implement new FunctionSignature for CallInfo's r=matklad a=vipentti

This introduces a new module `display` in `ra_ide_api` that contains UI-related things, in addition this refactors CallInfo's function signatures into a new `FunctionSignature` type, which implements `Display` and can be converted into `lsp_types::SignatureInformation` in the `conv` layer. 

Currently only `CallInfo` uses the `FunctionSignature` directly, but `function_label` now uses the same signature and returns it as a string, using the `Display` implementation.

This also fixes #960 

I think this similar structure could be applied to other UI-displayable items, so instead of the `ra_ide_api` returning `Strings` we could return some intermediate structures that can be converted into a UI-displayable `String` easily, but that could also provide some additional information.

Co-authored-by: Ville Penttinen <[email protected]>

4 files changed, 15 insertions, 12 deletions

diff --git a/crates/ra_ide_api/src/completion/complete_scope.rs b/crates/ra_ide_api/src/completion/complete_scope.rs
index 6146b7bb6..9d82f2270 100644
--- a/crates/ra_ide_api/src/completion/complete_scope.rs
+++ b/crates/ra_ide_api/src/completion/complete_scope.rs
@@ -145,7 +145,7 @@ mod tests {
         check_reference_completion(
             "dont_show_both_completions_for_shadowing",
             r"
-            fn foo() -> {
+            fn foo() {
                 let bar = 92;
                 {
                     let bar = 62;
diff --git a/crates/ra_ide_api/src/completion/presentation.rs b/crates/ra_ide_api/src/completion/presentation.rs
index 28c8f83ab..9aa346688 100644
--- a/crates/ra_ide_api/src/completion/presentation.rs
+++ b/crates/ra_ide_api/src/completion/presentation.rs
@@ -6,6 +6,9 @@ use ra_syntax::ast::NameOwner;
 
 use crate::completion::{
     Completions, CompletionKind, CompletionItemKind, CompletionContext, CompletionItem,
+};
+
+use crate::display::{
     function_label, const_label, type_label,
 };
 
@@ -101,7 +104,7 @@ impl Completions {
                 CompletionItemKind::Function
             })
             .set_documentation(func.docs(ctx.db))
-            .set_detail(detail);
+            .detail(detail);
         // If not an import, add parenthesis automatically.
         if ctx.use_item_syntax.is_none() && !ctx.is_call {
             tested_by!(inserts_parens_for_function_calls);
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 87691b304..34adcda6c 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
@@ -1,23 +1,23 @@
 ---
-created: "2019-02-18T09:22:24.188564584Z"
-creator: insta@0.6.2
+created: "2019-04-04T14:52:24.531844100Z"
+creator: insta@0.7.4
 source: crates/ra_ide_api/src/completion/completion_item.rs
 expression: kind_completions
 ---
 [
     CompletionItem {
         label: "bar",
-        source_range: [129; 129),
-        delete: [129; 129),
+        source_range: [126; 126),
+        delete: [126; 126),
         insert: "bar",
         kind: Binding
     },
     CompletionItem {
         label: "foo",
-        source_range: [129; 129),
-        delete: [129; 129),
+        source_range: [126; 126),
+        delete: [126; 126),
         insert: "foo()$0",
         kind: Function,
-        detail: "fn foo() ->"
+        detail: "fn foo()"
     }
 ]
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 0738cf466..ff36df707 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
@@ -1,6 +1,6 @@
 ---
-created: "2019-02-18T09:22:24.182964414Z"
-creator: insta@0.6.2
+created: "2019-04-04T14:52:24.525395600Z"
+creator: insta@0.7.4
 source: crates/ra_ide_api/src/completion/completion_item.rs
 expression: kind_completions
 ---
@@ -18,6 +18,6 @@ expression: kind_completions
         delete: [47; 47),
         insert: "x()$0",
         kind: Function,
-        detail: "fn x() ->"
+        detail: "fn x()"
     }
 ]