pass struct fields to chalk

Author: Austaras

src/tools/rust-analyzer/crates/hir-ty/src/chalk_db.rs

@@ -768,23 +768,21 @@ pub(crate) fn adt_datum_query(
         phantom_data,
     };
 
-    // this slows down rust-analyzer by quite a bit unfortunately, so enabling this is currently not worth it
-    let _variant_id_to_fields = |id: VariantId| {
+    let variant_id_to_fields = |id: VariantId| {
         let variant_data = &id.variant_data(db.upcast());
-        let fields = if variant_data.fields().is_empty() {
+        let fields = if variant_data.fields().is_empty() || bound_vars_subst.is_empty(Interner) {
             vec![]
         } else {
-            let field_types = db.field_types(id);
-            variant_data
-                .fields()
-                .iter()
-                .map(|(idx, _)| field_types[idx].clone().substitute(Interner, &bound_vars_subst))
-                .filter(|it| !it.contains_unknown())
-                .collect()
+            // HACK: provide full struct type info slows down rust-analyzer by quite a bit unfortunately,
+            // so we trick chalk into thinking that our struct impl Unsize
+            if let Some(ty) = bound_vars_subst.at(Interner, 0).ty(Interner) {
+                vec![ty.clone()]
+            } else {
+                vec![]
+            }
         };
         rust_ir::AdtVariantDatum { fields }
     };
-    let variant_id_to_fields = |_: VariantId| rust_ir::AdtVariantDatum { fields: vec![] };
 
     let (kind, variants) = match adt_id {
         hir_def::AdtId::StructId(id) => {

src/tools/rust-analyzer/crates/hir-ty/src/tests/coercion.rs

@@ -536,17 +536,15 @@ fn test() {
 
 #[test]
 fn coerce_unsize_generic() {
-    check(
+    check_no_mismatches(
         r#"
 //- minicore: coerce_unsized
 struct Foo<T> { t: T };
 struct Bar<T>(Foo<T>);
 
 fn test() {
     let _: &Foo<[usize]> = &Foo { t: [1, 2, 3] };
-                         //^^^^^^^^^^^^^^^^^^^^^ expected &'? Foo<[usize]>, got &'? Foo<[i32; 3]>
     let _: &Bar<[usize]> = &Bar(Foo { t: [1, 2, 3] });
-                         //^^^^^^^^^^^^^^^^^^^^^^^^^^ expected &'? Bar<[usize]>, got &'? Bar<[i32; 3]>
 }
 "#,
     );
@@ -958,3 +956,24 @@ fn f() {
     "#,
     );
 }
+
+#[test]
+fn coerce_nested_unsized_struct() {
+    check_types(
+        r#"
+//- minicore: fn, coerce_unsized, dispatch_from_dyn, sized
+use core::marker::Unsize;
+
+struct Foo<T: ?Sized>(T);
+
+fn need(_: &Foo<dyn Fn(i32) -> i32>) {
+}
+
+fn test() {
+    let callback = |x| x;
+                  //^ i32
+    need(&Foo(callback));
+}
+"#,
+    )
+}

src/tools/rust-analyzer/crates/hir-ty/src/tests/traits.rs

@@ -4694,21 +4694,21 @@ fn f<T: Send, U>() {
     Struct::<T>::IS_SEND;
   //^^^^^^^^^^^^^^^^^^^^Yes
     Struct::<U>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^^^{unknown}
     Struct::<*const T>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^^{unknown}
     Enum::<T>::IS_SEND;
   //^^^^^^^^^^^^^^^^^^Yes
     Enum::<U>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^{unknown}
     Enum::<*const T>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^^^^^^^^{unknown}
     Union::<T>::IS_SEND;
   //^^^^^^^^^^^^^^^^^^^Yes
     Union::<U>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^^{unknown}
     Union::<*const T>::IS_SEND;
-  //^^^^^^^^^^^^^^^^^^^^^^^^^^Yes
+  //^^^^^^^^^^^^^^^^^^^^^^^^^^{unknown}
     PhantomData::<T>::IS_SEND;
   //^^^^^^^^^^^^^^^^^^^^^^^^^Yes
     PhantomData::<U>::IS_SEND;