Don't pass SubstitutionMap by const reference

Author: slavapestov

lib/Sema/CSGen.cpp

@@ -3745,7 +3745,7 @@ void ConstraintSystem::optimizeConstraints(Expr *e) {
 
 bool swift::areGenericRequirementsSatisfied(
     const DeclContext *DC, const GenericSignature *sig,
-    const SubstitutionMap &Substitutions, bool isExtension) {
+    SubstitutionMap Substitutions, bool isExtension) {
 
   TypeChecker &TC = createTypeChecker(DC->getASTContext());
   ConstraintSystemOptions Options;

lib/Sema/ResilienceDiagnostics.cpp

@@ -228,7 +228,7 @@ static bool diagnoseDeclExportability(SourceLoc loc, const ValueDecl *D,
 
 static bool
 diagnoseGenericArgumentsExportability(SourceLoc loc,
-                                      const SubstitutionMap &subs,
+                                      SubstitutionMap subs,
                                       const SourceFile &userSF) {
   bool hadAnyIssues = false;
   for (ProtocolConformanceRef conformance : subs.getConformances()) {

lib/Sema/TypeCheckAccess.cpp

@@ -1516,7 +1516,7 @@ class ExportabilityChecker : public DeclVisitor<ExportabilityChecker> {
         diagnoseType(typeDecl, /*typeRepr*/nullptr);
       }
 
-      void visitSubstitutionMap(const SubstitutionMap &subs) {
+      void visitSubstitutionMap(SubstitutionMap subs) {
         for (ProtocolConformanceRef conformance : subs.getConformances()) {
           if (!conformance.isConcrete())
             continue;

lib/Sema/TypeChecker.h

@@ -2169,7 +2169,7 @@ bool fixDeclarationObjCName(InFlightDiagnostic &diag, ValueDecl *decl,
 
 bool areGenericRequirementsSatisfied(const DeclContext *DC,
                                      const GenericSignature *sig,
-                                     const SubstitutionMap &Substitutions,
+                                     SubstitutionMap Substitutions,
                                      bool isExtension);
 
 } // end namespace swift