Constify ReplaceOpaqueTypesWithUnderlyingTypes's DeclContext

No functionality change.

Author: jrose-apple

include/swift/AST/Types.h

@@ -4898,9 +4898,9 @@ enum class OpaqueSubstitutionKind {
 /// to their underlying types.
 class ReplaceOpaqueTypesWithUnderlyingTypes {
 public:
-  DeclContext *inContext;
+  const DeclContext *inContext;
   ResilienceExpansion contextExpansion;
-  ReplaceOpaqueTypesWithUnderlyingTypes(DeclContext *inContext,
+  ReplaceOpaqueTypesWithUnderlyingTypes(const DeclContext *inContext,
                                         ResilienceExpansion contextExpansion)
       : inContext(inContext), contextExpansion(contextExpansion) {}
 

lib/AST/Type.cpp

@@ -2647,7 +2647,7 @@ ReplaceOpaqueTypesWithUnderlyingTypes::shouldPerformSubstitution(
 }
 
 static Type
-substOpaqueTypesWithUnderlyingTypes(Type ty, DeclContext *inContext,
+substOpaqueTypesWithUnderlyingTypes(Type ty, const DeclContext *inContext,
                                     ResilienceExpansion contextExpansion) {
   ReplaceOpaqueTypesWithUnderlyingTypes replacer(inContext, contextExpansion);
   return ty.subst(replacer, replacer, SubstFlags::SubstituteOpaqueArchetypes);
@@ -2659,7 +2659,7 @@ substOpaqueTypesWithUnderlyingTypes(Type ty, DeclContext *inContext,
 /// This is purely an implementation detail check about whether type metadata
 /// will be accessible. It's not intended to enforce any rules about what
 /// opaque substitutions are or are not allowed.
-static bool canSubstituteTypeInto(Type ty, DeclContext *dc,
+static bool canSubstituteTypeInto(Type ty, const DeclContext *dc,
                                   OpaqueSubstitutionKind kind) {
   auto nominal = ty->getAnyNominal();
   if (!nominal)
@@ -2735,7 +2735,7 @@ operator()(SubstitutableType *maybeOpaqueType) const {
 
 static ProtocolConformanceRef
 substOpaqueTypesWithUnderlyingTypes(ProtocolConformanceRef ref, Type origType,
-                                    DeclContext *inContext,
+                                    const DeclContext *inContext,
                                     ResilienceExpansion contextExpansion) {
   ReplaceOpaqueTypesWithUnderlyingTypes replacer(inContext, contextExpansion);
   return ref.subst(origType, replacer, replacer,

lib/SILOptimizer/Transforms/SpecializeOpaqueArchetypes.cpp

@@ -31,7 +31,7 @@ llvm::cl::opt<bool>
 
 using namespace swift;
 
-static DeclContext *
+static const DeclContext *
 getDeclContextIfInCurrentModule(const SILFunction &fn) {
   auto *dc = fn.getDeclContext();
   auto *currentModule = fn.getModule().getSwiftModule();