Check for initialization of layout-restricted types

compiler/rustc_mir_build/src/check_unsafety.rs

@@ -10,6 +10,8 @@ use rustc_span::def_id::{DefId, LocalDefId};
 use rustc_span::symbol::Symbol;
 use rustc_span::Span;
 
+use std::ops::Bound;
+
 struct UnsafetyVisitor<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     thir: &'a Thir<'tcx>,
@@ -174,6 +176,17 @@ impl<'a, 'tcx> Visitor<'a, 'tcx> for UnsafetyVisitor<'a, 'tcx> {
                     self.requires_unsafe(expr.span, DerefOfRawPointer);
                 }
             }
+            ExprKind::Adt {
+                adt_def,
+                variant_index: _,
+                substs: _,
+                user_ty: _,
+                fields: _,
+                base: _,
+            } => match self.tcx.layout_scalar_valid_range(adt_def.did) {
+                (Bound::Unbounded, Bound::Unbounded) => {}
+                _ => self.requires_unsafe(expr.span, InitializingTypeWith),
+            },
             _ => {}
         }
 
@@ -216,7 +229,6 @@ impl BodyUnsafety {
 enum UnsafeOpKind {
     CallToUnsafeFunction,
     UseOfInlineAssembly,
-    #[allow(dead_code)] // FIXME
     InitializingTypeWith,
     #[allow(dead_code)] // FIXME
     CastOfPointerToInt,