4 files changed, 150 insertions, 36 deletions

diff --git a/crates/ra_ide/src/completion/complete_attribute.rs b/crates/ra_ide/src/completion/complete_attribute.rs
index f17266221..fb3f0b743 100644
--- a/crates/ra_ide/src/completion/complete_attribute.rs
+++ b/crates/ra_ide/src/completion/complete_attribute.rs
@@ -112,7 +112,7 @@ const ATTRIBUTES: &[AttrCompletion] = &[
     AttrCompletion { label: "repr", snippet: Some("repr(${0:C})"), should_be_inner: false },
     AttrCompletion {
         label: "should_panic",
-        snippet: Some(r#"expected = "${0:reason}""#),
+        snippet: Some(r#"should_panic(expected = "${0:reason}")"#),
         should_be_inner: false,
     },
     AttrCompletion {
@@ -571,7 +571,7 @@ mod tests {
                 label: "should_panic",
                 source_range: 19..19,
                 delete: 19..19,
-                insert: "expected = \"${0:reason}\"",
+                insert: "should_panic(expected = \"${0:reason}\")",
                 kind: Attribute,
             },
             CompletionItem {
@@ -810,7 +810,7 @@ mod tests {
                 label: "should_panic",
                 source_range: 20..20,
                 delete: 20..20,
-                insert: "expected = \"${0:reason}\"",
+                insert: "should_panic(expected = \"${0:reason}\")",
                 kind: Attribute,
             },
             CompletionItem {
diff --git a/crates/ra_ide/src/completion/complete_postfix.rs b/crates/ra_ide/src/completion/complete_postfix.rs
index f2a52a407..02e660ca8 100644
--- a/crates/ra_ide/src/completion/complete_postfix.rs
+++ b/crates/ra_ide/src/completion/complete_postfix.rs
@@ -184,6 +184,16 @@ pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
         &format!("dbg!({})", receiver_text),
     )
     .add_to(acc);
+
+    postfix_snippet(
+        ctx,
+        cap,
+        &dot_receiver,
+        "call",
+        "function(expr)",
+        &format!("${{1}}({})", receiver_text),
+    )
+    .add_to(acc);
 }
 
 fn get_receiver_text(receiver: &ast::Expr, receiver_is_ambiguous_float_literal: bool) -> String {
@@ -256,6 +266,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 89..89,
+                delete: 85..89,
+                insert: "${1}(bar)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 89..89,
                 delete: 85..89,
@@ -335,6 +352,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 210..210,
+                delete: 206..210,
+                insert: "${1}(bar)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 210..210,
                 delete: 206..210,
@@ -414,6 +438,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 211..211,
+                delete: 207..211,
+                insert: "${1}(bar)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 211..211,
                 delete: 207..211,
@@ -488,6 +519,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 91..91,
+                delete: 87..91,
+                insert: "${1}(bar)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 91..91,
                 delete: 87..91,
@@ -547,6 +585,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 52..52,
+                delete: 49..52,
+                insert: "${1}(42)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 52..52,
                 delete: 49..52,
@@ -608,6 +653,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 149..150,
+                delete: 145..150,
+                insert: "${1}(bar)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 149..150,
                 delete: 145..150,
@@ -667,6 +719,13 @@ mod tests {
                 detail: "Box::new(expr)",
             },
             CompletionItem {
+                label: "call",
+                source_range: 56..56,
+                delete: 49..56,
+                insert: "${1}(&&&&42)",
+                detail: "function(expr)",
+            },
+            CompletionItem {
                 label: "dbg",
                 source_range: 56..56,
                 delete: 49..56,
diff --git a/crates/ra_ide/src/completion/complete_trait_impl.rs b/crates/ra_ide/src/completion/complete_trait_impl.rs
index 039df03e0..21c9316e6 100644
--- a/crates/ra_ide/src/completion/complete_trait_impl.rs
+++ b/crates/ra_ide/src/completion/complete_trait_impl.rs
@@ -49,56 +49,53 @@ use crate::{
 pub(crate) fn complete_trait_impl(acc: &mut Completions, ctx: &CompletionContext) {
     if let Some((trigger, impl_def)) = completion_match(ctx) {
         match trigger.kind() {
-            SyntaxKind::NAME_REF => {
-                get_missing_assoc_items(&ctx.sema, &impl_def).iter().for_each(|item| match item {
+            SyntaxKind::NAME_REF => get_missing_assoc_items(&ctx.sema, &impl_def)
+                .into_iter()
+                .for_each(|item| match item {
                     hir::AssocItem::Function(fn_item) => {
-                        add_function_impl(&trigger, acc, ctx, &fn_item)
+                        add_function_impl(&trigger, acc, ctx, fn_item)
                     }
                     hir::AssocItem::TypeAlias(type_item) => {
-                        add_type_alias_impl(&trigger, acc, ctx, &type_item)
+                        add_type_alias_impl(&trigger, acc, ctx, type_item)
                     }
                     hir::AssocItem::Const(const_item) => {
-                        add_const_impl(&trigger, acc, ctx, &const_item)
+                        add_const_impl(&trigger, acc, ctx, const_item)
                     }
-                })
-            }
+                }),
 
             SyntaxKind::FN_DEF => {
-                for missing_fn in
-                    get_missing_assoc_items(&ctx.sema, &impl_def).iter().filter_map(|item| {
-                        match item {
-                            hir::AssocItem::Function(fn_item) => Some(fn_item),
-                            _ => None,
-                        }
+                for missing_fn in get_missing_assoc_items(&ctx.sema, &impl_def)
+                    .into_iter()
+                    .filter_map(|item| match item {
+                        hir::AssocItem::Function(fn_item) => Some(fn_item),
+                        _ => None,
                     })
                 {
-                    add_function_impl(&trigger, acc, ctx, &missing_fn);
+                    add_function_impl(&trigger, acc, ctx, missing_fn);
                 }
             }
 
             SyntaxKind::TYPE_ALIAS_DEF => {
-                for missing_fn in
-                    get_missing_assoc_items(&ctx.sema, &impl_def).iter().filter_map(|item| {
-                        match item {
-                            hir::AssocItem::TypeAlias(type_item) => Some(type_item),
-                            _ => None,
-                        }
+                for missing_fn in get_missing_assoc_items(&ctx.sema, &impl_def)
+                    .into_iter()
+                    .filter_map(|item| match item {
+                        hir::AssocItem::TypeAlias(type_item) => Some(type_item),
+                        _ => None,
                     })
                 {
-                    add_type_alias_impl(&trigger, acc, ctx, &missing_fn);
+                    add_type_alias_impl(&trigger, acc, ctx, missing_fn);
                 }
             }
 
             SyntaxKind::CONST_DEF => {
-                for missing_fn in
-                    get_missing_assoc_items(&ctx.sema, &impl_def).iter().filter_map(|item| {
-                        match item {
-                            hir::AssocItem::Const(const_item) => Some(const_item),
-                            _ => None,
-                        }
+                for missing_fn in get_missing_assoc_items(&ctx.sema, &impl_def)
+                    .into_iter()
+                    .filter_map(|item| match item {
+                        hir::AssocItem::Const(const_item) => Some(const_item),
+                        _ => None,
                     })
                 {
-                    add_const_impl(&trigger, acc, ctx, &missing_fn);
+                    add_const_impl(&trigger, acc, ctx, missing_fn);
                 }
             }
 
@@ -126,9 +123,9 @@ fn add_function_impl(
     fn_def_node: &SyntaxNode,
     acc: &mut Completions,
     ctx: &CompletionContext,
-    func: &hir::Function,
+    func: hir::Function,
 ) {
-    let signature = FunctionSignature::from_hir(ctx.db, *func);
+    let signature = FunctionSignature::from_hir(ctx.db, func);
 
     let fn_name = func.name(ctx.db).to_string();
 
@@ -167,7 +164,7 @@ fn add_type_alias_impl(
     type_def_node: &SyntaxNode,
     acc: &mut Completions,
     ctx: &CompletionContext,
-    type_alias: &hir::TypeAlias,
+    type_alias: hir::TypeAlias,
 ) {
     let alias_name = type_alias.name(ctx.db).to_string();
 
@@ -187,7 +184,7 @@ fn add_const_impl(
     const_def_node: &SyntaxNode,
     acc: &mut Completions,
     ctx: &CompletionContext,
-    const_: &hir::Const,
+    const_: hir::Const,
 ) {
     let const_name = const_.name(ctx.db).map(|n| n.to_string());
 
diff --git a/crates/ra_ide/src/completion/presentation.rs b/crates/ra_ide/src/completion/presentation.rs
index 440ffa31d..61565c84f 100644
--- a/crates/ra_ide/src/completion/presentation.rs
+++ b/crates/ra_ide/src/completion/presentation.rs
@@ -211,7 +211,7 @@ impl Completions {
             .parameter_names
             .iter()
             .skip(if function_signature.has_self_param { 1 } else { 0 })
-            .cloned()
+            .map(|name| name.trim_start_matches('_').into())
             .collect();
 
         builder = builder.add_call_parens(ctx, name, Params::Named(params));
@@ -672,6 +672,37 @@ mod tests {
         assert_debug_snapshot!(
             do_reference_completion(
                 r"
+                fn with_ignored_args(_foo: i32, ___bar: bool, ho_ge_: String) {}
+                fn main() { with_<|> }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "main()",
+                source_range: 110..115,
+                delete: 110..115,
+                insert: "main()$0",
+                kind: Function,
+                lookup: "main",
+                detail: "fn main()",
+            },
+            CompletionItem {
+                label: "with_ignored_args(…)",
+                source_range: 110..115,
+                delete: 110..115,
+                insert: "with_ignored_args(${1:foo}, ${2:bar}, ${3:ho_ge_})$0",
+                kind: Function,
+                lookup: "with_ignored_args",
+                detail: "fn with_ignored_args(_foo: i32, ___bar: bool, ho_ge_: String)",
+                trigger_call_info: true,
+            },
+        ]
+        "###
+        );
+        assert_debug_snapshot!(
+            do_reference_completion(
+                r"
                 struct S {}
                 impl S {
                     fn foo(&self) {}
@@ -695,6 +726,33 @@ mod tests {
         ]
         "###
         );
+        assert_debug_snapshot!(
+            do_reference_completion(
+                r"
+                struct S {}
+                impl S {
+                    fn foo_ignored_args(&self, _a: bool, b: i32) {}
+                }
+                fn bar(s: &S) {
+                    s.f<|>
+                }
+                "
+            ),
+            @r###"
+        [
+            CompletionItem {
+                label: "foo_ignored_args(…)",
+                source_range: 194..195,
+                delete: 194..195,
+                insert: "foo_ignored_args(${1:a}, ${2:b})$0",
+                kind: Method,
+                lookup: "foo_ignored_args",
+                detail: "fn foo_ignored_args(&self, _a: bool, b: i32)",
+                trigger_call_info: true,
+            },
+        ]
+        "###
+        );
     }
 
     #[test]