Provide an option to hide deprecated items from completion

Author: ChayimFriedman2

src/tools/rust-analyzer/crates/rust-analyzer/src/config.rs

@@ -429,6 +429,8 @@ config_data! {
         completion_callable_snippets: CallableCompletionDef  = CallableCompletionDef::FillArguments,
         /// Whether to show full function/method signatures in completion docs.
         completion_fullFunctionSignatures_enable: bool = false,
+        /// Whether to omit deprecated items from autocompletion. By default they are marked as deprecated but not hidden.
+        completion_hideDeprecated: bool = false,
         /// Maximum number of completions to return. If `None`, the limit is infinite.
         completion_limit: Option<usize> = None,
         /// Whether to show postfix snippets like `dbg`, `if`, `not`, etc.
@@ -1443,6 +1445,10 @@ impl Config {
         }
     }
 
+    pub fn completion_hide_deprecated(&self) -> bool {
+        *self.completion_hideDeprecated(None)
+    }
+
     pub fn detached_files(&self) -> &Vec<AbsPathBuf> {
         // FIXME @alibektas : This is the only config that is confusing. If it's a proper configuration
         // why is it not among the others? If it's client only which I doubt it is current state should be alright

src/tools/rust-analyzer/crates/rust-analyzer/src/lsp/to_proto.rs

@@ -228,8 +228,12 @@ pub(crate) fn completion_items(
     line_index: &LineIndex,
     version: Option<i32>,
     tdpp: lsp_types::TextDocumentPositionParams,
-    items: Vec<CompletionItem>,
+    mut items: Vec<CompletionItem>,
 ) -> Vec<lsp_types::CompletionItem> {
+    if config.completion_hide_deprecated() {
+        items.retain(|item| !item.deprecated);
+    }
+
     let max_relevance = items.iter().map(|it| it.relevance.score()).max().unwrap_or_default();
     let mut res = Vec::with_capacity(items.len());
     for item in items {

src/tools/rust-analyzer/docs/user/generated_config.adoc

@@ -283,6 +283,11 @@ Whether to add parenthesis and argument snippets when completing function.
 --
 Whether to show full function/method signatures in completion docs.
 --
+[[rust-analyzer.completion.hideDeprecated]]rust-analyzer.completion.hideDeprecated (default: `false`)::
++
+--
+Whether to omit deprecated items from autocompletion. By default they are marked as deprecated but not hidden.
+--
 [[rust-analyzer.completion.limit]]rust-analyzer.completion.limit (default: `null`)::
 +
 --

src/tools/rust-analyzer/editors/code/package.json

@@ -1077,6 +1077,16 @@
                     }
                 }
             },
+            {
+                "title": "completion",
+                "properties": {
+                    "rust-analyzer.completion.hideDeprecated": {
+                        "markdownDescription": "Whether to omit deprecated items from autocompletion. By default they are marked as deprecated but not hidden.",
+                        "default": false,
+                        "type": "boolean"
+                    }
+                }
+            },
             {
                 "title": "completion",
                 "properties": {