Auto merge of #17814 - ShoyuVanilla:object-safety, r=Veykril

feat: Implement object safety and its hovering hint

Resolves #17779

- [x] Fill missing implementations
- [x] Hover rendering
- [x] Implement object safety's own test suite, like layout
- [x] Add test cases (from rustc maybe)
- [x] Clean up ugly codes
- [x] Add doc string

crates/hir/src/lib.rs

@@ -66,7 +66,7 @@ use hir_ty::{
     diagnostics::BodyValidationDiagnostic,
     error_lifetime, known_const_to_ast,
     layout::{Layout as TyLayout, RustcEnumVariantIdx, RustcFieldIdx, TagEncoding},
-    method_resolution::{self},
+    method_resolution,
     mir::{interpret_mir, MutBorrowKind},
     primitive::UintTy,
     traits::FnTrait,
@@ -145,6 +145,7 @@ pub use {
         display::{ClosureStyle, HirDisplay, HirDisplayError, HirWrite},
         layout::LayoutError,
         mir::{MirEvalError, MirLowerError},
+        object_safety::{MethodViolationCode, ObjectSafetyViolation},
         FnAbi, PointerCast, Safety,
     },
     // FIXME: Properly encapsulate mir
@@ -2641,6 +2642,10 @@ impl Trait {
             .count()
     }
 
+    pub fn object_safety(&self, db: &dyn HirDatabase) -> Option<ObjectSafetyViolation> {
+        hir_ty::object_safety::object_safety(db, self.id)
+    }
+
     fn all_macro_calls(&self, db: &dyn HirDatabase) -> Box<[(AstId<ast::Item>, MacroCallId)]> {
         db.trait_data(self.id)
             .macro_calls