3 files changed, 91 insertions, 28 deletions

diff --git a/crates/ra_ide_api/src/call_info.rs b/crates/ra_ide_api/src/call_info.rs
index 1b279615c..c5e8d5843 100644
--- a/crates/ra_ide_api/src/call_info.rs
+++ b/crates/ra_ide_api/src/call_info.rs
@@ -1,7 +1,7 @@
 use test_utils::tested_by;
 use ra_db::SourceDatabase;
 use ra_syntax::{
-    AstNode, SyntaxNode, TextUnit, TextRange,
+    AstNode, SyntaxNode, TextUnit,
     SyntaxKind::FN_DEF,
     ast::{self, ArgListOwner},
     algo::find_node_at_offset,
@@ -38,28 +38,20 @@ pub(crate) fn call_info(db: &RootDatabase, position: FilePosition) -> Option<Cal
         }
     } else if num_params > 1 {
         // Count how many parameters into the call we are.
-        // TODO: This is best effort for now and should be fixed at some point.
-        // It may be better to see where we are in the arg_list and then check
-        // where offset is in that list (or beyond).
-        // Revisit this after we get documentation comments in.
         if let Some(ref arg_list) = calling_node.arg_list() {
             let arg_list_range = arg_list.syntax().range();
             if !arg_list_range.contains_inclusive(position.offset) {
                 tested_by!(call_info_bad_offset);
                 return None;
             }
-            let start = arg_list_range.start();
 
-            let range_search = TextRange::from_to(start, position.offset);
-            let mut commas: usize =
-                arg_list.syntax().text().slice(range_search).to_string().matches(',').count();
+            let param = arg_list
+                .args()
+                .position(|arg| arg.syntax().range().contains(position.offset))
+                .or(Some(num_params - 1))
+                .unwrap();
 
-            // If we have a method call eat the first param since it's just self.
-            if has_self {
-                commas += 1;
-            }
-
-            call_info.active_parameter = Some(commas);
+            call_info.active_parameter = Some(param);
         }
     }
 
diff --git a/crates/ra_ide_api/src/completion/complete_postfix.rs b/crates/ra_ide_api/src/completion/complete_postfix.rs
index 10a3c8db7..cf8c63269 100644
--- a/crates/ra_ide_api/src/completion/complete_postfix.rs
+++ b/crates/ra_ide_api/src/completion/complete_postfix.rs
@@ -15,7 +15,7 @@ use ra_syntax::{
 };
 use ra_text_edit::TextEditBuilder;
 
-fn postfix_snippet(ctx: &CompletionContext, label: &str, snippet: &str) -> Builder {
+fn postfix_snippet(ctx: &CompletionContext, label: &str, detail: &str, snippet: &str) -> Builder {
     let replace_range = ctx.source_range();
     let receiver_range = ctx.dot_receiver.expect("no receiver available").syntax().range();
     let delete_range = TextRange::from_to(receiver_range.start(), replace_range.start());
@@ -23,22 +23,33 @@ fn postfix_snippet(ctx: &CompletionContext, label: &str, snippet: &str) -> Build
     builder.delete(delete_range);
     CompletionItem::new(CompletionKind::Postfix, replace_range, label)
         .snippet(snippet)
+        .detail(detail)
         .text_edit(builder.finish())
 }
 
 pub(super) fn complete_postfix(acc: &mut Completions, ctx: &CompletionContext) {
     if let Some(dot_receiver) = ctx.dot_receiver {
         let receiver_text = dot_receiver.syntax().text().to_string();
-        postfix_snippet(ctx, "not", &format!("!{}", receiver_text)).add_to(acc);
-        postfix_snippet(ctx, "if", &format!("if {} {{$0}}", receiver_text)).add_to(acc);
+        postfix_snippet(ctx, "not", "!expr", &format!("!{}", receiver_text)).add_to(acc);
+        postfix_snippet(ctx, "ref", "&expr", &format!("&{}", receiver_text)).add_to(acc);
+        postfix_snippet(ctx, "refm", "&mut expr", &format!("&mut {}", receiver_text)).add_to(acc);
+        postfix_snippet(ctx, "if", "if expr {}", &format!("if {} {{$0}}", receiver_text))
+            .add_to(acc);
         postfix_snippet(
             ctx,
             "match",
+            "match expr {}",
             &format!("match {} {{\n${{1:_}} => {{$0\\}},\n}}", receiver_text),
         )
         .add_to(acc);
-        postfix_snippet(ctx, "while", &format!("while {} {{\n$0\n}}", receiver_text)).add_to(acc);
-        postfix_snippet(ctx, "dbg", &format!("dbg!({})", receiver_text)).add_to(acc);
+        postfix_snippet(
+            ctx,
+            "while",
+            "while expr {}",
+            &format!("while {} {{\n$0\n}}", receiver_text),
+        )
+        .add_to(acc);
+        postfix_snippet(ctx, "dbg", "dbg!(expr)", &format!("dbg!({})", receiver_text)).add_to(acc);
     }
 }
 
diff --git a/crates/ra_ide_api/src/completion/snapshots/completion_item__postfix_completion_works_for_trivial_path_expression.snap b/crates/ra_ide_api/src/completion/snapshots/completion_item__postfix_completion_works_for_trivial_path_expression.snap
index bc886ef0b..d3e53e4e8 100644
--- a/crates/ra_ide_api/src/completion/snapshots/completion_item__postfix_completion_works_for_trivial_path_expression.snap
+++ b/crates/ra_ide_api/src/completion/snapshots/completion_item__postfix_completion_works_for_trivial_path_expression.snap
@@ -1,15 +1,17 @@
 ---
-created: "2019-02-03T11:38:42.897384636+00:00"
-creator: [email protected]
-expression: kind_completions
+created: "2019-02-14T18:33:26.102469493Z"
+creator: [email protected]
 source: crates/ra_ide_api/src/completion/completion_item.rs
+expression: kind_completions
 ---
 [
     CompletionItem {
         completion_kind: Postfix,
         label: "dbg",
         kind: None,
-        detail: None,
+        detail: Some(
+            "dbg!(expr)"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -32,7 +34,9 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
         completion_kind: Postfix,
         label: "if",
         kind: None,
-        detail: None,
+        detail: Some(
+            "if expr {}"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -55,7 +59,9 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
         completion_kind: Postfix,
         label: "match",
         kind: None,
-        detail: None,
+        detail: Some(
+            "match expr {}"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -78,7 +84,9 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
         completion_kind: Postfix,
         label: "not",
         kind: None,
-        detail: None,
+        detail: Some(
+            "!expr"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(
@@ -99,9 +107,61 @@ source: crates/ra_ide_api/src/completion/completion_item.rs
     },
     CompletionItem {
         completion_kind: Postfix,
+        label: "ref",
+        kind: None,
+        detail: Some(
+            "&expr"
+        ),
+        documentation: None,
+        lookup: None,
+        insert_text: Some(
+            "&bar"
+        ),
+        insert_text_format: Snippet,
+        source_range: [76; 76),
+        text_edit: Some(
+            TextEdit {
+                atoms: [
+                    AtomTextEdit {
+                        delete: [72; 76),
+                        insert: ""
+                    }
+                ]
+            }
+        )
+    },
+    CompletionItem {
+        completion_kind: Postfix,
+        label: "refm",
+        kind: None,
+        detail: Some(
+            "&mut expr"
+        ),
+        documentation: None,
+        lookup: None,
+        insert_text: Some(
+            "&mut bar"
+        ),
+        insert_text_format: Snippet,
+        source_range: [76; 76),
+        text_edit: Some(
+            TextEdit {
+                atoms: [
+                    AtomTextEdit {
+                        delete: [72; 76),
+                        insert: ""
+                    }
+                ]
+            }
+        )
+    },
+    CompletionItem {
+        completion_kind: Postfix,
         label: "while",
         kind: None,
-        detail: None,
+        detail: Some(
+            "while expr {}"
+        ),
         documentation: None,
         lookup: None,
         insert_text: Some(