Merge #3574

3574: Fix completion of HashMap::new r=matklad a=flodiebold

The `ty` function in code_model returned the type with placeholders for type parameters. That's nice for printing, but not good for completion, because placeholders won't unify with anything else: So the type we got for `HashMap` was `HashMap<K, V, T>`, which doesn't unify with `HashMap<?, ?, RandomState>`, so the `new` method wasn't shown.

Now we instead return `HashMap<{unknown}, {unknown}, {unknown}>`, which does unify with the impl type. Maybe we should just expose this properly as variables though, i.e. we'd return something like `exists<type, type, type> HashMap<?0, ?1, ?2>` (in Chalk notation). It'll make the API more complicated, but harder to misuse. (And it would handle cases like `type TypeAlias<T> = HashMap<T, T>` more correctly.)

The `ty` function for fields was used for signature help, so there we want placeholders so that it looks nicer, I think. Hence I renamed it to `signature_ty`.

Co-authored-by: Florian Diebold <[email protected]>

1 files changed, 2 insertions, 2 deletions

diff --git a/crates/ra_ide/src/display/function_signature.rs b/crates/ra_ide/src/display/function_signature.rs
index 2c4c932de..ec1bbd5a0 100644
--- a/crates/ra_ide/src/display/function_signature.rs
+++ b/crates/ra_ide/src/display/function_signature.rs
@@ -64,7 +64,7 @@ impl FunctionSignature {
             .fields(db)
             .into_iter()
             .map(|field: hir::StructField| {
-                let ty = field.ty(db);
+                let ty = field.signature_ty(db);
                 format!("{}", ty.display(db))
             })
             .collect();
@@ -102,7 +102,7 @@ impl FunctionSignature {
             .into_iter()
             .map(|field: hir::StructField| {
                 let name = field.name(db);
-                let ty = field.ty(db);
+                let ty = field.signature_ty(db);
                 format!("{}: {}", name, ty.display(db))
             })
             .collect();