[Sema] error out on trait object reference comparison

Author: isuckatcs

src/sema.cpp

@@ -363,10 +363,16 @@ Sema::resolveBinaryOperator(res::Context &ctx,
     if (rhsTy->getAs<res::StructType>() || rhsTy->getAs<res::TypeParamType>())
       typeError = true;
 
-    for (auto &&ty : {lhsTy, rhsTy})
+    for (auto &&ty : {lhsTy, rhsTy}) {
+      if (ty->getAs<res::AnyTraitType>()) {
+        typeError = true;
+        continue;
+      }
+
       if (auto *ptr = ty->getAs<res::PointerType>();
           ptr && ptr->getPointeeType()->getAs<res::AnyTraitType>())
         typeError = true;
+    }
 
     if (!typeError) {
       lhs = hardenTypeIfNeeded(ctx, lhs, rhsTy);

test/sema/trait_objects/compare_ref_trait_objects.yl

@@ -0,0 +1,11 @@
+// RUN: compiler %s 2>&1 -res-dump | filecheck %s
+trait A {}
+
+extension number : A {}
+
+fn foo(a: &any A) {
+  // CHECK: [[# @LINE + 1 ]]:5: error: incompatible operands to binary operator ('any A' and 'any A')
+  a == a;
+}
+
+fn main() {}