Completition for type name? #3418

Iterate through TupleStructPat's until a MatchArm if
one exists. Store in a new is_pat_bind_and_path bool
and allow the `complete_scope` to find matches.

Added some tests to ensure it works in simple and nested cases.

1 files changed, 14 insertions, 2 deletions

diff --git a/crates/ra_ide/src/completion/completion_context.rs b/crates/ra_ide/src/completion/completion_context.rs
index 54589a2a8..d867ff6b2 100644
--- a/crates/ra_ide/src/completion/completion_context.rs
+++ b/crates/ra_ide/src/completion/completion_context.rs
@@ -36,6 +36,9 @@ pub(crate) struct CompletionContext<'a> {
     /// If a name-binding or reference to a const in a pattern.
     /// Irrefutable patterns (like let) are excluded.
     pub(super) is_pat_binding: bool,
+    // A bind battern which may also be part of a path.
+    // if let Some(En<|>) = Some(Enum::A)
+    pub(super) is_pat_binding_and_path: bool,
     /// A single-indent path, like `foo`. `::foo` should not be considered a trivial path.
     pub(super) is_trivial_path: bool,
     /// If not a trivial path, the prefix (qualifier).
@@ -95,6 +98,7 @@ impl<'a> CompletionContext<'a> {
             impl_def: None,
             is_param: false,
             is_pat_binding: false,
+            is_pat_binding_and_path: false,
             is_trivial_path: false,
             path_prefix: None,
             after_if: false,
@@ -186,12 +190,20 @@ impl<'a> CompletionContext<'a> {
         // suggest declaration names, see `CompletionKind::Magic`.
         if let Some(name) = find_node_at_offset::<ast::Name>(&file_with_fake_ident, offset) {
             if let Some(bind_pat) = name.syntax().ancestors().find_map(ast::BindPat::cast) {
-                let parent = bind_pat.syntax().parent();
+                let mut parent = bind_pat.syntax().parent();
                 if parent.clone().and_then(ast::MatchArm::cast).is_some()
-                    || parent.and_then(ast::Condition::cast).is_some()
+                    || parent.clone().and_then(ast::Condition::cast).is_some()
                 {
                     self.is_pat_binding = true;
                 }
+
+                while let Some(_) = parent.clone().and_then(ast::TupleStructPat::cast) {
+                    parent = parent.and_then(|p| p.parent());
+                    if parent.clone().and_then(ast::MatchArm::cast).is_some() {
+                        self.is_pat_binding_and_path = true;
+                        break;
+                    }
+                }
             }
             if is_node::<ast::Param>(name.syntax()) {
                 self.is_param = true;