Don't duplicate parens in patterns

crates/ra_ide/src/completion/completion_context.rs

@@ -63,6 +63,8 @@ pub(crate) struct CompletionContext<'a> {
     pub(super) dot_receiver_is_ambiguous_float_literal: bool,
     /// If this is a call (method or function) in particular, i.e. the () are already there.
     pub(super) is_call: bool,
+    /// Like `is_call`, but for tuple patterns.
+    pub(super) is_pattern_call: bool,
     /// If this is a macro call, i.e. the () are already there.
     pub(super) is_macro_call: bool,
     pub(super) is_path_type: bool,
@@ -136,6 +138,7 @@ impl<'a> CompletionContext<'a> {
             is_new_item: false,
             dot_receiver: None,
             is_call: false,
+            is_pattern_call: false,
             is_macro_call: false,
             is_path_type: false,
             has_type_args: false,
@@ -370,6 +373,8 @@ impl<'a> CompletionContext<'a> {
                 .and_then(|it| it.syntax().parent().and_then(ast::CallExpr::cast))
                 .is_some();
             self.is_macro_call = path.syntax().parent().and_then(ast::MacroCall::cast).is_some();
+            self.is_pattern_call =
+                path.syntax().parent().and_then(ast::TupleStructPat::cast).is_some();
 
             self.is_path_type = path.syntax().parent().and_then(ast::PathType::cast).is_some();
             self.has_type_args = segment.type_arg_list().is_some();

crates/ra_ide/src/completion/presentation.rs

@@ -384,10 +384,17 @@ impl Builder {
         if !ctx.config.add_call_parenthesis {
             return self;
         }
-        if ctx.use_item_syntax.is_some() || ctx.is_call {
+        if ctx.use_item_syntax.is_some() {
             mark::hit!(no_parens_in_use_item);
             return self;
         }
+        if ctx.is_pattern_call {
+            mark::hit!(dont_duplicate_pattern_parens);
+            return self;
+        }
+        if ctx.is_call {
+            return self;
+        }
 
         // Don't add parentheses if the expected type is some function reference.
         if let Some(ty) = &ctx.expected_type {
@@ -907,6 +914,30 @@ fn main(value: Option<i32>) {
         );
     }
 
+    #[test]
+    fn dont_duplicate_pattern_parens() {
+        mark::check!(dont_duplicate_pattern_parens);
+        check_edit(
+            "Var",
+            r#"
+enum E { Var(i32) }
+fn main() {
+    match E::Var(92) {
+        E::<|>(92) => (),
+    }
+}
+"#,
+            r#"
+enum E { Var(i32) }
+fn main() {
+    match E::Var(92) {
+        E::Var(92) => (),
+    }
+}
+"#,
+        );
+    }
+
     #[test]
     fn no_call_parens_if_fn_ptr_needed() {
         mark::check!(no_call_parens_if_fn_ptr_needed);