remove unnecessary if

while it could potentially not trigger due to a `default` assoc type with specialization,
it's only a perf improvement anyways

Author: lcnr

compiler/rustc_trait_selection/src/traits/select/mod.rs

@@ -1076,22 +1076,20 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                     obligation.predicate,
                     &mut nested_obligations,
                 );
-                if predicate != obligation.predicate {
-                    let mut nested_result = EvaluationResult::EvaluatedToOk;
-                    for obligation in nested_obligations {
-                        nested_result = cmp::max(
-                            this.evaluate_predicate_recursively(previous_stack, obligation)?,
-                            nested_result,
-                        );
-                    }
+                let mut nested_result = EvaluationResult::EvaluatedToOk;
+                for obligation in nested_obligations {
+                    nested_result = cmp::max(
+                        this.evaluate_predicate_recursively(previous_stack, obligation)?,
+                        nested_result,
+                    );
+                }
 
-                    if nested_result.must_apply_modulo_regions() {
-                        let obligation = obligation.with(this.tcx(), predicate);
-                        result = cmp::max(
-                            nested_result,
-                            this.evaluate_trait_predicate_recursively(previous_stack, obligation)?,
-                        );
-                    }
+                if nested_result.must_apply_modulo_regions() {
+                    let obligation = obligation.with(this.tcx(), predicate);
+                    result = cmp::max(
+                        nested_result,
+                        this.evaluate_trait_predicate_recursively(previous_stack, obligation)?,
+                    );
                 }
             }