Avoid unnecessary duplicates in Completion Lists (#998)

language_service/src/completion.rs

@@ -11,6 +11,7 @@ use crate::qsc_utils::{protocol_span, span_contains};
 use qsc::ast::visit::{self, Visitor};
 use qsc::hir::{ItemKind, Package, PackageId};
 use qsc::resolve::{Local, LocalKind};
+use rustc_hash::FxHashSet;
 use std::rc::Rc;
 
 const PRELUDE: [&str; 3] = [
@@ -157,19 +158,19 @@ fn get_indent(compilation: &Compilation, package_offset: u32) -> String {
 
 struct CompletionListBuilder {
     current_sort_group: u32,
-    items: Vec<CompletionItem>,
+    items: FxHashSet<CompletionItem>,
 }
 
 impl CompletionListBuilder {
     fn new() -> Self {
         CompletionListBuilder {
             current_sort_group: 1,
-            items: Vec::new(),
+            items: FxHashSet::default(),
         }
     }
 
     fn into_items(self) -> Vec<CompletionItem> {
-        self.items
+        self.items.into_iter().collect()
     }
 
     fn push_item_decl_keywords(&mut self) {

language_service/src/protocol.rs

@@ -11,7 +11,7 @@ pub struct WorkspaceConfigurationUpdate {
 }
 
 /// Represents a span of text used by the Language Server API
-#[derive(Debug, PartialEq, Clone, Copy)]
+#[derive(Debug, PartialEq, Eq, Clone, Copy, Hash)]
 pub struct Span {
     pub start: u32,
     pub end: u32,
@@ -24,7 +24,7 @@ pub struct DiagnosticUpdate {
     pub errors: Vec<Error>,
 }
 
-#[derive(Copy, Clone, Debug, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
 #[allow(clippy::module_name_repetitions)]
 pub enum CompletionItemKind {
     // It would have been nice to match the numeric values to the ones used by
@@ -68,6 +68,30 @@ impl CompletionItem {
     }
 }
 
+impl PartialEq for CompletionItem {
+    // exclude sort text for comparison
+    fn eq(&self, other: &Self) -> bool {
+        self.label == other.label
+            && self.kind == other.kind
+            && self.detail == other.detail
+            && self.additional_text_edits == other.additional_text_edits
+    }
+}
+
+impl Eq for CompletionItem {}
+
+use std::hash::{Hash, Hasher};
+
+impl Hash for CompletionItem {
+    // exclude sort text for hashing
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        self.label.hash(state);
+        self.kind.hash(state);
+        self.detail.hash(state);
+        self.additional_text_edits.hash(state);
+    }
+}
+
 #[derive(Debug, PartialEq)]
 pub struct Location {
     pub source: String,