Eliminate all vestiges of Substitution and SubstitutionList.

Introduced during the bring-up of the generics system in July, 2012,
Substitution (and SubstitutionList) has been completely superseded by
SubstitutionMap. R.I.P.

Author: DougGregor

include/swift/AST/ASTContext.h

@@ -21,7 +21,6 @@
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/Identifier.h"
 #include "swift/AST/SearchPathOptions.h"
-#include "swift/AST/SubstitutionList.h"
 #include "swift/AST/Type.h"
 #include "swift/AST/TypeAlignments.h"
 #include "swift/Basic/LangOptions.h"
@@ -95,7 +94,6 @@ namespace swift {
   class SourceManager;
   class ValueDecl;
   class DiagnosticEngine;
-  class Substitution;
   class TypeCheckerDebugConsumer;
   struct RawComment;
   class DocComment;

include/swift/AST/GenericEnvironment.h

@@ -17,7 +17,6 @@
 #ifndef SWIFT_AST_GENERIC_ENVIRONMENT_H
 #define SWIFT_AST_GENERIC_ENVIRONMENT_H
 
-#include "swift/AST/SubstitutionList.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/GenericParamKey.h"

include/swift/AST/GenericSignature.h

@@ -19,7 +19,6 @@
 
 #include "swift/AST/PrintOptions.h"
 #include "swift/AST/Requirement.h"
-#include "swift/AST/SubstitutionList.h"
 #include "swift/AST/Type.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/FoldingSet.h"
@@ -32,7 +31,6 @@ namespace swift {
 class GenericSignatureBuilder;
 class ProtocolConformanceRef;
 class ProtocolType;
-class Substitution;
 class SubstitutionMap;
 
 /// An access path used to find a particular protocol conformance within
@@ -177,9 +175,9 @@ class alignas(1 << TypeAlignInBits) GenericSignature final
     return Mem;
   }
 
-  /// Build an interface type substitution map from a vector of Substitutions
-  /// that correspond to the generic parameters in this generic signature.
-  SubstitutionMap getSubstitutionMap(SubstitutionList args) const;
+  /// Build a substitution map for this generic signature by looking up
+  /// substitutions in the given substitution map.
+  SubstitutionMap getSubstitutionMap(SubstitutionMap subs) const;
 
   /// Build an interface type substitution map from a type substitution function
   /// and conformance lookup function.
@@ -193,11 +191,6 @@ class alignas(1 << TypeAlignInBits) GenericSignature final
   Optional<ProtocolConformanceRef>
   lookupConformance(CanType depTy, ProtocolDecl *proto) const;
 
-  /// Build an array of substitutions from an interface type substitution map,
-  /// using the given function to look up conformances.
-  void getSubstitutions(const SubstitutionMap &subMap,
-                        SmallVectorImpl<Substitution> &result) const;
-
   /// Enumerate all of the dependent types in the type signature that will
   /// occur in substitution lists (in order), along with the set of
   /// conformance requirements placed on that dependent type.

include/swift/AST/LazyResolver.h

@@ -33,7 +33,6 @@ class NominalTypeDecl;
 class NormalProtocolConformance;
 class ProtocolConformance;
 class ProtocolDecl;
-class Substitution;
 class TypeDecl;
 class ValueDecl;
 class VarDecl;

include/swift/AST/ProtocolConformance.h

@@ -18,7 +18,6 @@
 
 #include "swift/AST/ConcreteDeclRef.h"
 #include "swift/AST/Decl.h"
-#include "swift/AST/SubstitutionList.h"
 #include "swift/AST/Type.h"
 #include "swift/AST/Types.h"
 #include "swift/AST/TypeAlignments.h"

include/swift/AST/Substitution.h

@@ -31,13 +31,9 @@ namespace swift {
 
 class GenericSignature;
 class GenericEnvironment;
-class Substitution;
 class SubstitutableType;
 typedef CanTypeWrapper<GenericTypeParamType> CanGenericTypeParamType;
 
-// FIXME: Soon this will go away.
-using SubstitutionList = ArrayRef<Substitution>;
-
 template<class Type> class CanTypeWrapper;
 typedef CanTypeWrapper<SubstitutableType> CanSubstitutableType;
 
@@ -109,10 +105,9 @@ class SubstitutionMap {
   }
 
   /// Build an interface type substitution map for the given generic
-  /// signature and a vector of Substitutions that correspond to the
-  /// requirements of this generic signature.
+  /// signature using the mapping in the given substitutions.
   static SubstitutionMap get(GenericSignature *genericSig,
-                             SubstitutionList substitutions);
+                             SubstitutionMap substitutions);
 
   /// Build an interface type substitution map for the given generic signature
   /// from a type substitution function and conformance lookup function.
@@ -196,14 +191,6 @@ class SubstitutionMap {
                            GenericSignature *derivedSig,
                            Optional<SubstitutionMap> derivedSubs);
 
-  /// Produce a substitution list for the given substitution map.
-  ///
-  /// Note: we are moving away from using Substitutions, so this should only
-  /// be used at the edges where part of the compiler is still working
-  /// directly with Substitution/SubstitutionList and hasn't been converted
-  /// to SubstitutionMap.
-  SubstitutionList toList() const;
-
   /// Combine two substitution maps as follows.
   ///
   /// The result is written in terms of the generic parameters of 'genericSig'.

include/swift/AST/SubstitutionList.h

@@ -45,7 +45,6 @@ namespace swift {
   class ProtocolConformance;
   class SILFunction;
   class Stmt;
-  class Substitution;
   class TypeVariableType;
   class TypeBase;
   class TypeDecl;

include/swift/AST/SubstitutionMap.h

@@ -24,7 +24,6 @@
 #include "swift/AST/ProtocolConformanceRef.h"
 #include "swift/AST/Requirement.h"
 #include "swift/AST/SILLayout.h"
-#include "swift/AST/SubstitutionList.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Type.h"
 #include "swift/AST/TypeAlignments.h"

include/swift/AST/TypeAlignments.h

@@ -19,7 +19,6 @@
 #define SWIFT_AST_WITNESS_H
 
 #include "swift/AST/ConcreteDeclRef.h"
-#include "swift/AST/SubstitutionList.h"
 #include "llvm/ADT/PointerUnion.h"
 #include "llvm/Support/Compiler.h"
 

include/swift/AST/Types.h

@@ -65,7 +65,6 @@ class SILArgument;
 class SILUndef;
 class Stmt;
 class StringLiteralExpr;
-class Substitution;
 class ValueDecl;
 class VarDecl;
 class FunctionRefInst;

include/swift/AST/Witness.h

@@ -77,7 +77,7 @@ class TypeSubstCloner : public SILClonerWithScopes<ImplClass> {
             RecursiveSubs = AI.getFunction()
                                ->getLoweredFunctionType()
                                ->getGenericSignature()
-                               ->getSubstitutionMap(Subs.toList());
+                               ->getSubstitutionMap(Subs);
 
             // Use the new set of substitutions to compute the new
             // substituted callee type.

include/swift/SIL/SILInstruction.h

@@ -2792,20 +2792,6 @@ void TypeRepr::dump() const {
   llvm::errs() << '\n';
 }
 
-void Substitution::dump() const {
-  dump(llvm::errs());
-}
-
-void Substitution::dump(llvm::raw_ostream &out, unsigned indent) const {
-  out.indent(indent);
-  print(out);
-  out << '\n';
-
-  for (auto &c : Conformance) {
-    c.dump(out, indent + 2);
-  }
-}
-
 void ProtocolConformanceRef::dump() const {
   dump(llvm::errs());
 }
@@ -2822,14 +2808,6 @@ void ProtocolConformanceRef::dump(llvm::raw_ostream &out,
   }
 }
 
-void swift::dump(SubstitutionList subs) {
-  unsigned i = 0;
-  for (const auto &s : subs) {
-    llvm::errs() << i++ << ": ";
-    s.dump();
-  }
-}
-
 void ProtocolConformance::dump() const {
   auto &out = llvm::errs();
   dump(out);

include/swift/SIL/TypeSubstCloner.h

@@ -4176,11 +4176,6 @@ void ProtocolConformance::printName(llvm::raw_ostream &os,
   }
 }
 
-void Substitution::print(llvm::raw_ostream &os,
-                         const PrintOptions &PO) const {
-  Replacement->print(os, PO);
-}
-
 void swift::printEnumElementsAsCases(
     llvm::DenseSet<EnumElementDecl *> &UnhandledElements,
     llvm::raw_ostream &OS) {

lib/AST/ASTDumper.cpp

@@ -48,7 +48,6 @@ add_swift_library(swiftAST STATIC
   SyntaxASTMap.cpp
   SILLayout.cpp
   Stmt.cpp
-  Substitution.cpp
   SubstitutionMap.cpp
   SwiftNameTranslation.cpp
   Type.cpp

lib/AST/ASTPrinter.cpp

@@ -466,7 +466,7 @@ bool GenericSignature::enumeratePairedRequirements(
 }
 
 SubstitutionMap
-GenericSignature::getSubstitutionMap(SubstitutionList subs) const {
+GenericSignature::getSubstitutionMap(SubstitutionMap subs) const {
   return SubstitutionMap::get(const_cast<GenericSignature *>(this), subs);
 }
 
@@ -478,43 +478,6 @@ getSubstitutionMap(TypeSubstitutionFn subs,
                               subs, lookupConformance);
 }
 
-void GenericSignature::
-getSubstitutions(const SubstitutionMap &subMap,
-                 SmallVectorImpl<Substitution> &result) const {
-
-  // Enumerate all of the requirements that require substitution.
-  enumeratePairedRequirements([&](Type depTy, ArrayRef<Requirement> reqs) {
-    auto &ctx = getASTContext();
-
-    // Compute the replacement type.
-    Type currentReplacement = depTy.subst(subMap);
-    if (!currentReplacement)
-      currentReplacement = ErrorType::get(depTy);
-
-    // Collect the conformances.
-    SmallVector<ProtocolConformanceRef, 4> currentConformances;
-    for (auto req: reqs) {
-      assert(req.getKind() == RequirementKind::Conformance);
-      auto protoDecl = req.getSecondType()->castTo<ProtocolType>()->getDecl();
-      if (auto conformance = subMap.lookupConformance(depTy->getCanonicalType(),
-                                                      protoDecl)) {
-        currentConformances.push_back(*conformance);
-      } else {
-        if (!currentReplacement->hasError())
-          currentReplacement = ErrorType::get(currentReplacement);
-        currentConformances.push_back(ProtocolConformanceRef(protoDecl));
-      }
-    }
-
-    // Add it to the final substitution list.
-    result.push_back({
-      currentReplacement,
-      ctx.AllocateCopy(currentConformances)
-    });
-
-    return false;
-  });
-}
 
 bool GenericSignature::requiresClass(Type type) {
   if (!type->isTypeParameter()) return false;