AST: Remove GenericEnvironment::OwningDC

Author: slavapestov

include/swift/AST/GenericEnvironment.h

@@ -59,7 +59,6 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
         : private llvm::TrailingObjects<GenericEnvironment, Type> {
   GenericSignature *Signature = nullptr;
   GenericSignatureBuilder *Builder = nullptr;
-  DeclContext *OwningDC = nullptr;
 
   friend TrailingObjects;
 
@@ -98,18 +97,6 @@ class alignas(1 << DeclAlignInBits) GenericEnvironment final
   GenericEnvironment *getIncomplete(GenericSignature *signature,
                                     GenericSignatureBuilder *builder);
 
-  /// Set the owning declaration context for this generic environment.
-  void setOwningDeclContext(DeclContext *owningDC);
-
-  /// Retrieve the declaration context that owns this generic environment, if
-  /// there is one.
-  ///
-  /// Note that several generic environments may refer to the same declaration
-  /// context, because non-generic declarations nested within generic ones
-  /// inherit the enclosing generic environment. In such cases, the owning
-  /// context is the outermost context.
-  DeclContext *getOwningDeclContext() const { return OwningDC; }
-
   /// Add a mapping of a generic parameter to a specific type (which may be
   /// an archetype)
   void addMapping(GenericParamKey key, Type contextType);

lib/AST/ASTDumper.cpp

@@ -3519,10 +3519,6 @@ namespace {
       printArchetypeCommon(T, "primary_archetype_type", label);
       printField("name", T->getFullName());
       OS << "\n";
-      auto genericEnv = T->getGenericEnvironment();
-      if (auto owningDC = genericEnv->getOwningDeclContext()) {
-        owningDC->printContext(OS, Indent + 2);
-      }
       printArchetypeNestedTypes(T);
       PrintWithColorRAII(OS, ParenthesisColor) << ')';
     }

lib/AST/ASTVerifier.cpp

@@ -667,14 +667,6 @@ class Verifier : public ASTWalker {
             Out << "AST verification error: archetype "
                 << root->getString() << " not allowed in this context\n";
 
-            if (auto env = rootPrimary->getGenericEnvironment()) {
-              if (auto owningDC = env->getOwningDeclContext()) {
-                llvm::errs() << "archetype came from:\n";
-                owningDC->dumpContext();
-                llvm::errs() << "\n";
-              }
-            }
-
             return true;
           }
 

lib/AST/Decl.cpp

@@ -874,8 +874,6 @@ void GenericContext::setGenericEnvironment(GenericEnvironment *genericEnv) {
             genericEnv->getGenericSignature()->getCanonicalSignature()) &&
          "set a generic environment with a different generic signature");
   this->GenericSigOrEnv = genericEnv;
-  if (genericEnv)
-    genericEnv->setOwningDeclContext(this);
 }
 
 GenericEnvironment *

lib/AST/GenericEnvironment.cpp

@@ -55,35 +55,6 @@ GenericEnvironment::GenericEnvironment(GenericSignature *signature,
                           Type());
 }
 
-void GenericEnvironment::setOwningDeclContext(DeclContext *newOwningDC) {
-  if (!OwningDC) {
-    OwningDC = newOwningDC;
-    return;
-  }
-
-  if (!newOwningDC || OwningDC == newOwningDC)
-    return;
-
-  // Find the least common ancestor context to be the owner.
-  unsigned oldDepth = OwningDC->getSyntacticDepth();
-  unsigned newDepth = newOwningDC->getSyntacticDepth();
-
-  while (oldDepth > newDepth) {
-    OwningDC = OwningDC->getParent();
-    --oldDepth;
-  }
-
-  while (newDepth > oldDepth) {
-    newOwningDC = newOwningDC->getParent();
-    --newDepth;
-  }
-
-  while (OwningDC != newOwningDC) {
-    OwningDC = OwningDC->getParent();
-    newOwningDC = newOwningDC->getParent();
-  }
-}
-
 void GenericEnvironment::addMapping(GenericParamKey key,
                                     Type contextType) {
   // Find the index into the parallel arrays of generic parameters and

lib/Sema/CSDiag.cpp

@@ -3357,17 +3357,16 @@ bool FailureDiagnosis::diagnoseArgumentGenericRequirements(
     }
   };
 
-  auto *dc = env->getOwningDeclContext();
   auto substitutionFn = QueryTypeSubstitutionMap{substitutions};
   RequirementsListener genericReqListener(CS, AFD, substitutionFn,
                                           callExpr, fnExpr, argExpr);
 
   auto result = TC.checkGenericArguments(
-      dc, callExpr->getLoc(), fnExpr->getLoc(), AFD->getInterfaceType(),
+      AFD, callExpr->getLoc(), fnExpr->getLoc(), AFD->getInterfaceType(),
       env->getGenericSignature()->getGenericParams(),
       env->getGenericSignature()->getRequirements(),
       substitutionFn,
-      LookUpConformanceInModule{dc->getParentModule()},
+      LookUpConformanceInModule{AFD->getParentModule()},
       ConformanceCheckFlags::SuppressDependencyTracking, &genericReqListener);
 
   // Note: If result is RequirementCheckResult::SubstitutionFailure, we did