[NFC] Sema: get rid of redundant DeclContext parameter to checkConfor…

include/swift/AST/DeclContext.h

@@ -813,7 +813,10 @@ class IterableDeclContext {
   const Decl *getDecl() const;
 
   /// Return 'this' as a \c GenericContext.
-  const GenericContext *getAsGenericContext() const;
+  GenericContext *getAsGenericContext();
+  const GenericContext *getAsGenericContext() const {
+    return const_cast<IterableDeclContext *>(this)->getAsGenericContext();
+  }
 
   /// Get the DeclID this Decl was deserialized from.
   serialization::DeclID getDeclID() const {

lib/AST/DeclContext.cpp

@@ -773,7 +773,7 @@ IterableDeclContext::getDecl() const {
   llvm_unreachable("Unhandled IterableDeclContextKind in switch.");
 }
 
-const GenericContext *IterableDeclContext::getAsGenericContext() const {
+GenericContext *IterableDeclContext::getAsGenericContext() {
   switch (getIterableContextKind()) {
   case IterableDeclContextKind::NominalTypeDecl:
     return cast<NominalTypeDecl>(this);

lib/Sema/DerivedConformanceCodable.cpp

@@ -372,7 +372,7 @@ static EnumDecl *synthesizeCodingKeysEnum(DerivedConformance &derived) {
     return nullptr;
 
   // Forcibly derive conformance to CodingKey.
-  TypeChecker::checkConformancesInContext(enumDecl, enumDecl);
+  TypeChecker::checkConformancesInContext(enumDecl);
 
   // Add to the type.
   target->addMember(enumDecl);

lib/Sema/TypeCheckDeclPrimary.cpp

@@ -1759,7 +1759,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclCircularity(ED);
 
-    TypeChecker::checkConformancesInContext(ED, ED);
+    TypeChecker::checkConformancesInContext(ED);
   }
 
   void visitStructDecl(StructDecl *SD) {
@@ -1789,7 +1789,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclCircularity(SD);
 
-    TypeChecker::checkConformancesInContext(SD, SD);
+    TypeChecker::checkConformancesInContext(SD);
   }
 
   /// Check whether the given properties can be @NSManaged in this class.
@@ -2023,7 +2023,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkDeclCircularity(CD);
 
-    TypeChecker::checkConformancesInContext(CD, CD);
+    TypeChecker::checkConformancesInContext(CD);
 
     maybeDiagnoseClassWithoutInitializers(CD);
   }
@@ -2362,7 +2362,7 @@ class DeclChecker : public DeclVisitor<DeclChecker> {
 
     TypeChecker::checkPatternBindingCaptures(ED);
 
-    TypeChecker::checkConformancesInContext(ED, ED);
+    TypeChecker::checkConformancesInContext(ED);
 
     TypeChecker::checkDeclAttributes(ED);
     checkAccessControl(ED);

lib/Sema/TypeCheckProtocol.cpp

@@ -5034,25 +5034,19 @@ LookupAllConformancesInContextRequest::evaluate(
   return IDC->getLocalConformances(ConformanceLookupKind::All);
 }
 
-void TypeChecker::checkConformancesInContext(DeclContext *dc,
-                                             IterableDeclContext *idc) {
+void TypeChecker::checkConformancesInContext(IterableDeclContext *idc) {
+  auto *const dc = idc->getAsGenericContext();
+
   // For anything imported from Clang, lazily check conformances.
   if (isa<ClangModuleUnit>(dc->getModuleScopeContext()))
     return;
 
+  const auto *const nominal = dc->getSelfNominalTypeDecl();
+  if (!nominal)
+    return;
+
   // Determine the access level of this conformance.
-  Decl *currentDecl = nullptr;
-  AccessLevel defaultAccess;
-  if (auto ext = dyn_cast<ExtensionDecl>(dc)) {
-    const NominalTypeDecl *nominal = ext->getExtendedNominal();
-    if (!nominal)
-      return;
-    defaultAccess = nominal->getFormalAccess();
-    currentDecl = ext;
-  } else {
-    defaultAccess = cast<NominalTypeDecl>(dc)->getFormalAccess();
-    currentDecl = cast<NominalTypeDecl>(dc);
-  }
+  const auto defaultAccess = nominal->getFormalAccess();
 
   // Check each of the conformances associated with this context.
   auto conformances =

lib/Sema/TypeChecker.h

@@ -915,7 +915,7 @@ ProtocolConformanceRef conformsToProtocol(Type T, ProtocolDecl *Proto,
 void checkConformance(NormalProtocolConformance *conformance);
 
 /// Check all of the conformances in the given context.
-void checkConformancesInContext(DeclContext *dc, IterableDeclContext *idc);
+void checkConformancesInContext(IterableDeclContext *idc);
 
 /// Check that the type of the given property conforms to NSCopying.
 ProtocolConformanceRef checkConformanceToNSCopying(VarDecl *var);