Add Escapable conformance to some builtin functions

Author: meg-gupta

lib/AST/Builtins.cpp

@@ -2114,9 +2114,13 @@ static ValueDecl *getOnceOperation(ASTContext &Context,
 static ValueDecl *getPolymorphicBinaryOperation(ASTContext &ctx,
                                                 Identifier id) {
   BuiltinFunctionBuilder builder(ctx);
-  builder.addParameter(makeGenericParam());
-  builder.addParameter(makeGenericParam());
-  builder.setResult(makeGenericParam());
+
+  // Builtins of the form: func binOp<T>(_ t: T, _ t: T) -> T
+  auto genericParam = makeGenericParam();
+  builder.addConformanceRequirement(genericParam, KnownProtocolKind::Escapable);
+  builder.addParameter(genericParam);
+  builder.addParameter(genericParam);
+  builder.setResult(genericParam);
   return builder.build(id);
 }
 
@@ -2230,6 +2234,7 @@ static ValueDecl *getEmplace(ASTContext &ctx, Identifier id) {
   BuiltinFunctionBuilder builder(ctx, /* genericParamCount */ 1);
 
   auto T = makeGenericParam();
+  builder.addConformanceRequirement(T, KnownProtocolKind::Escapable);
 
   auto fnParamTy = FunctionType::get(FunctionType::Param(ctx.TheRawPointerType),
                                      ctx.TheEmptyTupleType,

lib/AST/ConformanceLookup.cpp

@@ -850,6 +850,10 @@ static bool conformsToInvertible(CanType type, InvertibleProtocolKind ip) {
   if (type->is<SILPackType>())
     return true;
 
+  if (type->is<SILTokenType>()) {
+    return true;
+  }
+
   // The SIL types in the AST do not have real conformances, and should have
   // been handled in SILType instead.
   assert(!(type->is<SILBoxType,