AST: Factor out GenericTypeParamType::withDepth()

Author: slavapestov

include/swift/AST/SubstitutionMap.h

@@ -306,7 +306,6 @@ class LookUpConformanceInSubstitutionMap {
 };
 
 struct OverrideSubsInfo {
-  ASTContext &Ctx;
   unsigned BaseDepth;
   unsigned OrigDepth;
   SubstitutionMap BaseSubMap;

include/swift/AST/Types.h

@@ -7366,6 +7366,8 @@ class GenericTypeParamType : public SubstitutableType,
 
   Type getValueType() const;
 
+  GenericTypeParamType *withDepth(unsigned depth) const;
+
   void Profile(llvm::FoldingSetNodeID &ID) {
     // Note: We explicitly don't use 'getName()' because for canonical forms
     // which don't store an identifier we'll go create a tau based form. We

lib/AST/RequirementEnvironment.cpp

@@ -46,10 +46,8 @@ RequirementEnvironment::RequirementEnvironment(
 
   auto conformanceToWitnessThunkGenericParamFn = [&](GenericTypeParamType *genericParam)
       -> GenericTypeParamType * {
-    return GenericTypeParamType::get(genericParam->getParamKind(),
-                                     genericParam->getDepth() + (covariantSelf ? 1 : 0),
-                                     genericParam->getIndex(),
-                                     genericParam->getValueType(), ctx);
+    return genericParam->withDepth(
+        genericParam->getDepth() + (covariantSelf ? 1 : 0));
   };
 
   // This is a substitution function from the generic parameters of the
@@ -109,9 +107,7 @@ RequirementEnvironment::RequirementEnvironment(
       // invalid code.
       if (genericParam->getDepth() != 1)
         return Type();
-      Type substGenericParam = GenericTypeParamType::get(
-          genericParam->getParamKind(), depth, genericParam->getIndex(),
-          genericParam->getValueType(), ctx);
+      Type substGenericParam = genericParam->withDepth(depth);
       if (genericParam->isParameterPack()) {
         substGenericParam = PackType::getSingletonPackExpansion(
             substGenericParam);
@@ -210,10 +206,7 @@ RequirementEnvironment::RequirementEnvironment(
     }
 
     // Create an equivalent generic parameter at the next depth.
-    auto substGenericParam = GenericTypeParamType::get(
-        genericParam->getParamKind(), depth, genericParam->getIndex(),
-        genericParam->getValueType(), ctx);
-
+    auto substGenericParam = genericParam->withDepth(depth);
     genericParamTypes.push_back(substGenericParam);
   }
 

lib/AST/SubstitutionMap.cpp

@@ -427,8 +427,7 @@ OverrideSubsInfo::OverrideSubsInfo(const NominalTypeDecl *baseNominal,
                                    const NominalTypeDecl *derivedNominal,
                                    GenericSignature baseSig,
                                    const GenericParamList *derivedParams)
-  : Ctx(baseSig->getASTContext()),
-    BaseDepth(0),
+  : BaseDepth(0),
     OrigDepth(0),
     DerivedParams(derivedParams) {
 
@@ -468,10 +467,7 @@ Type QueryOverrideSubs::operator()(SubstitutableType *type) const {
             ->getDeclaredInterfaceType();
       }
 
-      return GenericTypeParamType::get(
-          gp->getParamKind(),
-          gp->getDepth() + info.OrigDepth - info.BaseDepth,
-          gp->getIndex(), gp->getValueType(), info.Ctx);
+      return gp->withDepth(gp->getDepth() + info.OrigDepth - info.BaseDepth);
     }
   }
 

lib/AST/Type.cpp

@@ -2163,6 +2163,14 @@ Type GenericTypeParamType::getValueType() const {
   return ValueType;
 }
 
+GenericTypeParamType *GenericTypeParamType::withDepth(unsigned depth) const {
+  return GenericTypeParamType::get(getParamKind(),
+                                   depth,
+                                   getIndex(),
+                                   getValueType(),
+                                   getASTContext());
+}
+
 const llvm::fltSemantics &BuiltinFloatType::getAPFloatSemantics() const {
   switch (getFPKind()) {
   case BuiltinFloatType::IEEE16:  return APFloat::IEEEhalf();

lib/SILOptimizer/Utils/Devirtualize.cpp

@@ -405,21 +405,15 @@ combineSubstitutionMaps(SubstitutionMap firstSubMap,
                         unsigned firstDepth,
                         unsigned secondDepth,
                         GenericSignature genericSig) {
-  auto &ctx = genericSig->getASTContext();
-
   return SubstitutionMap::get(
     genericSig,
     [&](SubstitutableType *type) {
       auto *gp = cast<GenericTypeParamType>(type);
       if (gp->getDepth() < firstDepth)
         return QuerySubstitutionMap{firstSubMap}(gp);
 
-      auto *replacement = GenericTypeParamType::get(
-          gp->getParamKind(),
-          gp->getDepth() + secondDepth - firstDepth,
-          gp->getIndex(),
-          gp->getValueType(),
-          ctx);
+      auto *replacement = gp->withDepth(
+          gp->getDepth() + secondDepth - firstDepth);
       return QuerySubstitutionMap{secondSubMap}(replacement);
     },
     // We might not have enough information in the substitution maps alone.
@@ -1056,16 +1050,13 @@ getWitnessMethodSubstitutions(
         }
 
         if (depth < baseDepth) {
-          paramType = GenericTypeParamType::get(paramType->getParamKind(),
-              depth, paramType->getIndex(), paramType->getValueType(), ctx);
-
+          paramType = paramType->withDepth(depth);
           return Type(paramType).subst(baseSubMap);
         }
 
         depth = depth - baseDepth + 1;
 
-        paramType = GenericTypeParamType::get(paramType->getParamKind(),
-            depth, paramType->getIndex(), paramType->getValueType(), ctx);
+        paramType = paramType->withDepth(depth);
         return Type(paramType).subst(origSubMap);
       },
       [&](CanType type, Type substType, ProtocolDecl *proto) {
@@ -1084,10 +1075,8 @@ getWitnessMethodSubstitutions(
 
         if (depth < baseDepth) {
           type = CanType(type.transformRec([&](TypeBase *t) -> std::optional<Type> {
-            if (t == paramType) {
-              return Type(GenericTypeParamType::get(paramType->getParamKind(),
-                  depth, paramType->getIndex(), paramType->getValueType(), ctx));
-            }
+            if (t == paramType)
+              return paramType->withDepth(depth);
 
             assert(!isa<GenericTypeParamType>(t));
             return std::nullopt;
@@ -1099,10 +1088,8 @@ getWitnessMethodSubstitutions(
         depth = depth - baseDepth + 1;
 
         type = CanType(type.transformRec([&](TypeBase *t) -> std::optional<Type> {
-          if (t == paramType) {
-            return Type(GenericTypeParamType::get(paramType->getParamKind(),
-                depth, paramType->getIndex(), paramType->getValueType(), ctx));
-          }
+          if (t == paramType)
+            return paramType->withDepth(depth);
 
           assert(!isa<GenericTypeParamType>(t));
           return std::nullopt;

lib/Sema/TypeCheckProtocol.cpp

@@ -1034,11 +1034,7 @@ findMissingGenericRequirementForSolutionFix(
           return conformance->getType();
 
         ASSERT(gp->getDepth() > 0);
-        gp = GenericTypeParamType::get(gp->getParamKind(),
-                                       gp->getDepth() - 1,
-                                       gp->getIndex(),
-                                       gp->getValueType(),
-                                       ctx);
+        gp = gp->withDepth(gp->getDepth() - 1);
       }
 
       if (!sig)