AST: Use getNextDepth()/getMaxDepth()

Author: slavapestov

lib/AST/ASTContext.cpp

@@ -5884,11 +5884,8 @@ CanGenericSignature ASTContext::getSingleGenericParameterSignature() const {
 
 Type OpenedArchetypeType::getSelfInterfaceTypeFromContext(GenericSignature parentSig,
                                                           ASTContext &ctx) {
-  unsigned depth = 0;
-  if (!parentSig.getGenericParams().empty())
-    depth = parentSig.getGenericParams().back()->getDepth() + 1;
   return GenericTypeParamType::get(/*isParameterPack=*/ false,
-                                   /*depth=*/ depth, /*index=*/ 0,
+                                   parentSig.getNextDepth(), /*index=*/ 0,
                                    ctx);
 }
 

lib/AST/ASTMangler.cpp

@@ -2748,7 +2748,7 @@ void ASTMangler::appendContextualInverses(const GenericTypeDecl *contextDecl,
   parts.params = std::nullopt;
 
   // The depth of parameters for this extension is +1 of the extended signature.
-  parts.initialParamDepth = sig.getGenericParams().back()->getDepth() + 1;
+  parts.initialParamDepth = sig.getNextDepth();
 
   appendModule(module, alternateModuleName);
   appendGenericSignatureParts(sig, parts);
@@ -3391,7 +3391,7 @@ void ASTMangler::gatherGenericSignatureParts(GenericSignature sig,
   } else {
     inverseReqs.clear();
   }
-  base.setDepth(canSig.getGenericParams().back()->getDepth());
+  base.setDepth(canSig->getMaxDepth());
 
   unsigned &initialParamDepth = parts.initialParamDepth;
   auto &genericParams = parts.params;
@@ -3412,7 +3412,7 @@ void ASTMangler::gatherGenericSignatureParts(GenericSignature sig,
 
   // The signature depth starts above the depth of the context signature.
   if (!contextSig.getGenericParams().empty()) {
-    initialParamDepth = contextSig.getGenericParams().back()->getDepth() + 1;
+    initialParamDepth = contextSig.getNextDepth();
   }
 
   // If both signatures have exactly the same requirements, ignoring
@@ -4760,11 +4760,10 @@ static std::optional<unsigned> getEnclosingTypeGenericDepth(const Decl *decl) {
   if (!typeDecl)
     return std::nullopt;
 
-  auto genericParams = typeDecl->getGenericParams();
-  if (!genericParams)
+  if (!typeDecl->isGeneric())
     return std::nullopt;
 
-  return genericParams->getParams().back()->getDepth();
+  return typeDecl->getGenericSignature()->getMaxDepth();
 }
 
 ASTMangler::BaseEntitySignature::BaseEntitySignature(const Decl *decl)

lib/AST/ASTPrinter.cpp

@@ -1807,10 +1807,7 @@ void PrintAST::printSingleDepthOfGenericSignature(
       auto *DC = Current->getInnermostDeclContext()->getInnermostTypeContext();
       M = DC->getParentModule();
       subMap = CurrentType->getContextSubstitutionMap(M, DC);
-      if (!subMap.empty()) {
-        typeContextDepth = subMap.getGenericSignature()
-            .getGenericParams().back()->getDepth() + 1;
-      }
+      typeContextDepth = subMap.getGenericSignature().getNextDepth();
     }
   }
 
@@ -7075,7 +7072,7 @@ class TypePrinter : public TypeVisitor<TypePrinter> {
 
     // The element archetypes are at a depth one past the max depth
     // of the base signature.
-    unsigned elementDepth = params.back()->getDepth() + 1;
+    unsigned elementDepth = sig.getNextDepth();
 
     // Transform the archetype's interface type to be based on the
     // corresponding non-canonical type parameter.

lib/AST/GenericSignature.cpp

@@ -79,7 +79,7 @@ ArrayRef<GenericTypeParamType *>
 GenericSignatureImpl::getInnermostGenericParams() const {
   const auto params = getGenericParams();
 
-  const unsigned maxDepth = params.back()->getDepth();
+  const unsigned maxDepth = getMaxDepth();
   if (params.front()->getDepth() == maxDepth)
     return params;
 

lib/AST/RequirementEnvironment.cpp

@@ -77,13 +77,9 @@ RequirementEnvironment::RequirementEnvironment(
 
   // Calculate the depth at which the requirement's generic parameters
   // appear in the witness thunk signature.
-  unsigned depth = 0;
-  if (covariantSelf) {
+  unsigned depth = conformanceSig.getNextDepth();
+  if (covariantSelf)
     ++depth;
-  }
-  if (conformanceSig) {
-    depth += conformanceSig.getGenericParams().back()->getDepth() + 1;
-  }
 
   // Build a substitution map to replace the protocol's \c Self and the type
   // parameters of the requirement into a combined context that provides the

lib/AST/SubstitutionMap.cpp

@@ -578,7 +578,7 @@ OverrideSubsInfo::OverrideSubsInfo(const NominalTypeDecl *baseNominal,
     DerivedParams(derivedParams) {
 
   if (auto baseNominalSig = baseNominal->getGenericSignature()) {
-    BaseDepth = baseNominalSig.getGenericParams().back()->getDepth() + 1;
+    BaseDepth = baseNominalSig.getNextDepth();
 
     auto *genericEnv = derivedNominal->getGenericEnvironment();
     auto derivedNominalTy = derivedNominal->getDeclaredInterfaceType();
@@ -602,7 +602,7 @@ OverrideSubsInfo::OverrideSubsInfo(const NominalTypeDecl *baseNominal,
   }
 
   if (auto derivedNominalSig = derivedNominal->getGenericSignature())
-    OrigDepth = derivedNominalSig.getGenericParams().back()->getDepth() + 1;
+    OrigDepth = derivedNominalSig.getNextDepth();
 }
 
 Type QueryOverrideSubs::operator()(SubstitutableType *type) const {