Sema: Remove some usages of TypeSubstitutionMap

Author: slavapestov

lib/Sema/AssociatedTypeInference.cpp

@@ -2685,10 +2685,8 @@ bool AssociatedTypeInference::simplifyCurrentTypeWitnesses() {
       abort();
     }
 
-    TypeSubstitutionMap substitutions;
-    auto selfTy = cast<SubstitutableType>(
-        proto->getSelfInterfaceType()->getCanonicalType());
-    substitutions[selfTy] = dc->mapTypeIntoContext(conformance->getType());
+    auto selfTy = proto->getSelfInterfaceType()->getCanonicalType();
+    auto substSelfTy = dc->mapTypeIntoContext(conformance->getType());
 
     for (auto assocType : proto->getAssociatedTypeMembers()) {
       if (conformance->hasTypeWitness(assocType))
@@ -2716,13 +2714,14 @@ bool AssociatedTypeInference::simplifyCurrentTypeWitnesses() {
           if (!type->isTypeParameter())
             return std::nullopt;
 
-          auto *rootParam = type->getRootGenericParam();
-          assert(rootParam->isEqual(selfTy));
-
           // Replace Self with the concrete conforming type.
-          auto substType = Type(type).subst(QueryTypeSubstitutionMap{substitutions},
-                                            LookUpConformanceInModule(),
-                                            options);
+          auto substType = Type(type).subst(
+              [&](SubstitutableType *type) -> Type {
+                ASSERT(type->isEqual(selfTy));
+                return substSelfTy;
+              },
+              LookUpConformanceInModule(),
+              options);
 
           // If we don't have enough type witnesses to substitute fully,
           // leave the original type parameter in place.
@@ -2914,12 +2913,12 @@ bool AssociatedTypeInference::checkCurrentTypeWitnesses(
 
 bool AssociatedTypeInference::checkConstrainedExtension(ExtensionDecl *ext) {
   auto typeInContext = dc->mapTypeIntoContext(adoptee);
-  auto subs = typeInContext->getContextSubstitutions(ext);
+  auto subs = typeInContext->getContextSubstitutionMap(ext->getExtendedNominal());
 
   SubstOptions options = getSubstOptionsWithCurrentTypeWitnesses();
   switch (checkRequirements(
       ext->getGenericSignature().getRequirements(),
-      QueryTypeSubstitutionMap{subs}, options)) {
+      QuerySubstitutionMap{subs}, options)) {
   case CheckRequirementsResult::Success:
   case CheckRequirementsResult::SubstitutionFailure:
     return false;

lib/Sema/TypeCheckType.cpp

@@ -643,9 +643,9 @@ bool TypeChecker::checkContextualRequirements(GenericTypeDecl *decl,
       noteLoc = loc;
   }
 
-  const auto subMap = parentTy->getContextSubstitutions(dc);
+  const auto subMap = parentTy->getContextSubstitutionMap(dc);
   const auto substitutions = [&](SubstitutableType *type) -> Type {
-    auto result = QueryTypeSubstitutionMap{subMap}(type);
+    auto result = QuerySubstitutionMap{subMap}(type);
     if (result->hasTypeParameter()) {
       if (contextSig) {
         // Avoid building this generic environment unless we need it.