[NFC] Add a convenience function to IFS

Author: rjmccall

include/swift/AST/InFlightSubstitution.h

@@ -59,6 +59,10 @@ class InFlightSubstitution {
     return Options;
   }
 
+  bool shouldSubstituteOpaqueArchetypes() const {
+    return Options.contains(SubstFlags::SubstituteOpaqueArchetypes);
+  }
+
   /// Is the given type invariant to substitution?
   bool isInvariant(Type type) const;
 };

lib/AST/ProtocolConformanceRef.cpp

@@ -86,7 +86,7 @@ ProtocolConformanceRef::subst(Type origType, InFlightSubstitution &IFS) const {
   // If the type is an opaque archetype, the conformance will remain abstract,
   // unless we're specifically substituting opaque types.
   if (auto origArchetype = origType->getAs<ArchetypeType>()) {
-    if (!IFS.getOptions().contains(SubstFlags::SubstituteOpaqueArchetypes)
+    if (!IFS.shouldSubstituteOpaqueArchetypes()
         && isa<OpaqueTypeArchetypeType>(origArchetype)) {
       return *this;
     }

lib/AST/SubstitutionMap.cpp

@@ -485,7 +485,7 @@ SubstitutionMap SubstitutionMap::subst(InFlightSubstitution &IFS) const {
     // Fast path for concrete case -- we don't need to compute substType
     // at all.
     if (conformance.isConcrete() &&
-        !IFS.getOptions().contains(SubstFlags::SubstituteOpaqueArchetypes)) {
+        !IFS.shouldSubstituteOpaqueArchetypes()) {
       newConformances.push_back(
         ProtocolConformanceRef(conformance.getConcrete()->subst(IFS)));
     } else {

lib/AST/Type.cpp

@@ -4655,7 +4655,7 @@ static Type substGenericFunctionType(GenericFunctionType *genericFnType,
 bool InFlightSubstitution::isInvariant(Type derivedType) const {
   return !derivedType->hasArchetype()
       && !derivedType->hasTypeParameter()
-      && (!Options.contains(SubstFlags::SubstituteOpaqueArchetypes)
+      && (!shouldSubstituteOpaqueArchetypes()
           || !derivedType->hasOpaqueArchetype());
 }
 
@@ -4742,13 +4742,13 @@ static Type substType(Type derivedType, InFlightSubstitution &IFS) {
 
     // Opaque types can't normally be directly substituted unless we
     // specifically were asked to substitute them.
-    if (!IFS.getOptions().contains(SubstFlags::SubstituteOpaqueArchetypes)
+    if (!IFS.shouldSubstituteOpaqueArchetypes()
         && isa<OpaqueTypeArchetypeType>(substOrig))
       return None;
 
     // If we have a substitution for this type, use it.
     if (auto known = IFS.substType(substOrig)) {
-      if (IFS.getOptions().contains(SubstFlags::SubstituteOpaqueArchetypes) &&
+      if (IFS.shouldSubstituteOpaqueArchetypes() &&
           isa<OpaqueTypeArchetypeType>(substOrig) &&
           known->getCanonicalType() == substOrig->getCanonicalType())
         return None; // Recursively process the substitutions of the opaque type