AST: Simplify RequirementEnvironment construction a bit more

Author: slavapestov

lib/AST/RequirementEnvironment.cpp

@@ -116,33 +116,26 @@ RequirementEnvironment::RequirementEnvironment(
         InFlightSubstitution &IFS, Type type, ProtocolDecl *proto)
           -> ProtocolConformanceRef {
       // The protocol 'Self' conforms concretely to the conforming type.
-      if (type->isEqual(ctx.TheSelfType)) {
-        auto replacement = type.subst(IFS);
-        ASSERT(covariantSelf || replacement->isEqual(substConcreteType));
-
-        if (conformance) {
-          ProtocolConformance *specialized = conformance;
-
-          if (conformance->getGenericSignature()) {
-            auto concreteSubs =
-              substConcreteType->getContextSubstitutionMap(conformanceDC);
-            specialized =
-              ctx.getSpecializedConformance(substConcreteType,
-                                            cast<NormalProtocolConformance>(conformance),
-                                            concreteSubs);
-          }
-
-          // findWitnessedObjCRequirements() does a weird thing by passing in a
-          // DC that is not the conformance DC. Work around it here.
-          if (!specialized->getType()->isEqual(replacement)) {
-            ASSERT(specialized->getType()->isExactSuperclassOf(substConcreteType));
-            ASSERT(covariantSelf ? replacement->is<GenericTypeParamType>()
-                                 : replacement->isEqual(substConcreteType));
-            specialized = ctx.getInheritedConformance(replacement, specialized);
-          }
-
-          return ProtocolConformanceRef(specialized);
+      if (type->isEqual(ctx.TheSelfType) && !covariantSelf && conformance) {
+        ProtocolConformance *specialized = conformance;
+
+        if (conformance->getGenericSignature()) {
+          auto concreteSubs =
+            substConcreteType->getContextSubstitutionMap(conformanceDC);
+          specialized =
+            ctx.getSpecializedConformance(substConcreteType,
+                                          cast<NormalProtocolConformance>(conformance),
+                                          concreteSubs);
+        }
+
+        // findWitnessedObjCRequirements() does a weird thing by passing in a
+        // DC that is not the conformance DC. Work around it here.
+        if (!specialized->getType()->isEqual(substConcreteType)) {
+          ASSERT(specialized->getType()->isExactSuperclassOf(substConcreteType));
+          specialized = ctx.getInheritedConformance(substConcreteType, specialized);
         }
+
+        return ProtocolConformanceRef(specialized);
       }
 
       // All other generic parameters come from the requirement itself