1 files changed, 58 insertions, 2 deletions

diff --git a/crates/completion/src/completions.rs b/crates/completion/src/completions.rs
index c3ce6e51d..3b582ed07 100644
--- a/crates/completion/src/completions.rs
+++ b/crates/completion/src/completions.rs
@@ -15,7 +15,9 @@ pub(crate) mod trait_impl;
 pub(crate) mod mod_;
 pub(crate) mod flyimport;
 
-use hir::{ModPath, ScopeDef, Type};
+use std::iter;
+
+use hir::{known, ModPath, ScopeDef, Type};
 
 use crate::{
     item::Builder,
@@ -118,7 +120,18 @@ impl Completions {
         variant: hir::Variant,
         local_name: Option<hir::Name>,
     ) {
-        if let Some(item) = render_variant_pat(RenderContext::new(ctx), variant, local_name) {
+        if let Some(item) = render_variant_pat(RenderContext::new(ctx), variant, local_name, None) {
+            self.add(item);
+        }
+    }
+
+    pub(crate) fn add_qualified_variant_pat(
+        &mut self,
+        ctx: &CompletionContext,
+        variant: hir::Variant,
+        path: ModPath,
+    ) {
+        if let Some(item) = render_variant_pat(RenderContext::new(ctx), variant, None, Some(path)) {
             self.add(item);
         }
     }
@@ -166,3 +179,46 @@ impl Completions {
         self.add(item);
     }
 }
+
+fn complete_enum_variants(
+    acc: &mut Completions,
+    ctx: &CompletionContext,
+    ty: &hir::Type,
+    cb: impl Fn(&mut Completions, &CompletionContext, hir::Variant, hir::ModPath),
+) {
+    if let Some(hir::Adt::Enum(enum_data)) =
+        iter::successors(Some(ty.clone()), |ty| ty.remove_ref()).last().and_then(|ty| ty.as_adt())
+    {
+        let variants = enum_data.variants(ctx.db);
+
+        let module = if let Some(module) = ctx.scope.module() {
+            // Compute path from the completion site if available.
+            module
+        } else {
+            // Otherwise fall back to the enum's definition site.
+            enum_data.module(ctx.db)
+        };
+
+        if let Some(impl_) = ctx.impl_def.as_ref().and_then(|impl_| ctx.sema.to_def(impl_)) {
+            if impl_.target_ty(ctx.db) == *ty {
+                for &variant in &variants {
+                    let self_path = hir::ModPath::from_segments(
+                        hir::PathKind::Plain,
+                        iter::once(known::SELF_TYPE).chain(iter::once(variant.name(ctx.db))),
+                    );
+                    cb(acc, ctx, variant, self_path);
+                }
+            }
+        }
+
+        for variant in variants {
+            if let Some(path) = module.find_use_path(ctx.db, hir::ModuleDef::from(variant)) {
+                // Variants with trivial paths are already added by the existing completion logic,
+                // so we should avoid adding these twice
+                if path.segments().len() > 1 {
+                    cb(acc, ctx, variant, path);
+                }
+            }
+        }
+    }
+}