Merge #3108

3108: Magic Completion for `impl Trait for` Associated Items r=matklad a=kdelorey

# Summary
This PR adds a set of magic completions to auto complete associated trait items (functions/consts/types). 

![Associated Trait Impl](https://user-images.githubusercontent.com/2295721/74493144-d8f1af00-4e96-11ea-93a4-82725bf89646.gif)

## Notes
Since the assist and completion share the same logic when figuring out the associated items that are missing, a shared utility was created in the `ra_assists::utils` module.

Resolves #1046 

As this is my first PR to the rust-analyzer project, I'm new to the codebase, feedback welcomed!

Co-authored-by: Kevin DeLorey <[email protected]>

1 files changed, 3 insertions, 0 deletions

diff --git a/crates/ra_ide/src/completion.rs b/crates/ra_ide/src/completion.rs
index fedc02e14..4bdc6ba23 100644
--- a/crates/ra_ide/src/completion.rs
+++ b/crates/ra_ide/src/completion.rs
@@ -15,6 +15,7 @@ mod complete_path;
 mod complete_scope;
 mod complete_postfix;
 mod complete_macro_in_item_position;
+mod complete_trait_impl;
 
 use ra_db::SourceDatabase;
 use ra_ide_db::RootDatabase;
@@ -74,5 +75,7 @@ pub(crate) fn completions(db: &RootDatabase, position: FilePosition) -> Option<C
     complete_pattern::complete_pattern(&mut acc, &ctx);
     complete_postfix::complete_postfix(&mut acc, &ctx);
     complete_macro_in_item_position::complete_macro_in_item_position(&mut acc, &ctx);
+    complete_trait_impl::complete_trait_impl(&mut acc, &ctx);
+
     Some(acc)
 }