[SILGen] Eliminate emitApplyOfLibraryIntrinsic() for SubstitutionList.

There was only one caller; update it to use the SubstitutionMap version.

Author: DougGregor

lib/SILGen/SILGenApply.cpp

@@ -4469,18 +4469,6 @@ SILGenFunction::emitApplyOfLibraryIntrinsic(SILLocation loc,
                    finalArgs, calleeTypeInfo, ApplyOptions::None, ctx);
 }
 
-RValue
-SILGenFunction::emitApplyOfLibraryIntrinsic(SILLocation loc,
-                                            FuncDecl *fn,
-                                            const SubstitutionList &subs,
-                                            ArrayRef<ManagedValue> args,
-                                            SGFContext ctx) {
-  SubstitutionMap subMap;
-  if (auto genericSig = fn->getGenericSignature())
-    subMap = genericSig->getSubstitutionMap(subs);
-  return emitApplyOfLibraryIntrinsic(loc, fn, subMap, args, ctx);
-}
-
 static StringRef
 getMagicFunctionString(SILGenFunction &SGF) {
   assert(SGF.MagicFunctionName

lib/SILGen/SILGenFunction.h

@@ -1335,12 +1335,6 @@ class LLVM_LIBRARY_VISIBILITY SILGenFunction
                                      ArrayRef<ManagedValue> args,
                                      SGFContext ctx);
 
-  RValue emitApplyOfLibraryIntrinsic(SILLocation loc,
-                                     FuncDecl *fn,
-                                     const SubstitutionList &subs,
-                                     ArrayRef<ManagedValue> args,
-                                     SGFContext ctx);
-
   SILValue emitApplyWithRethrow(SILLocation loc, SILValue fn,
                                 SILType substFnType,
                                 SubstitutionMap subs,

lib/SILGen/SILGenPattern.cpp

@@ -2588,10 +2588,24 @@ static void emitDiagnoseOfUnexpectedEnumCaseValue(SILGenFunction &SGF,
                                                       loweredRawType);
   auto materializedRawValue = rawValue.materialize(SGF, loc);
 
-  Substitution subs[] = {
-    {switchedValueSwiftType, /*Conformances*/None},
-    {enumDecl->getRawType(), /*Conformances*/None},
-  };
+  auto genericSig = diagnoseFailure->getGenericSignature();
+  auto subs = genericSig->getSubstitutionMap(
+      [&](SubstitutableType *type) -> Type {
+        auto genericParam = cast<GenericTypeParamType>(type);
+        assert(genericParam->getDepth() == 0);
+        assert(genericParam->getIndex() < 2);
+        switch (genericParam->getIndex()) {
+        case 0:
+          return switchedValueSwiftType;
+
+        case 1:
+          return enumDecl->getRawType();
+
+        default:
+          llvm_unreachable("wrong generic signature for expected case value");
+        }
+      },
+      LookUpConformanceInSignature(*genericSig));
 
   SGF.emitApplyOfLibraryIntrinsic(loc, diagnoseFailure, subs,
                                   {ManagedValue::forUnmanaged(metatype),