AST: Add GenericParamList::setDeclContext()

Author: slavapestov

include/swift/AST/Decl.h

@@ -1309,6 +1309,8 @@ class GenericParamList final :
   /// for more information.
   void setOuterParameters(GenericParamList *Outer) { OuterParameters = Outer; }
 
+  void setDeclContext(DeclContext *dc);
+
   SourceLoc getLAngleLoc() const { return Brackets.Start; }
   SourceLoc getRAngleLoc() const { return Brackets.End; }
 

lib/AST/Decl.cpp

@@ -964,6 +964,11 @@ void GenericParamList::setDepth(unsigned depth) {
     param->setDepth(depth);
 }
 
+void GenericParamList::setDeclContext(DeclContext *dc) {
+  for (auto param : *this)
+    param->setDeclContext(dc);
+}
+
 TrailingWhereClause::TrailingWhereClause(
                        SourceLoc whereLoc,
                        ArrayRef<RequirementRepr> requirements)

lib/AST/NameLookupRequests.cpp

@@ -233,10 +233,9 @@ Optional<GenericParamList *> GenericParamListRequest::getCachedResult() const {
 
 void GenericParamListRequest::cacheResult(GenericParamList *params) const {
   auto *context = std::get<0>(getStorage());
-  if (params) {
-    for (auto param : *params)
-      param->setDeclContext(context);
-  }
+  if (params)
+    params->setDeclContext(context);
+
   context->GenericParamsAndBit.setPointerAndInt(params, true);
 }