SIL: SILFunctionTypes don't allow generic signatures where all parameters are concrete

Author: slavapestov

lib/AST/ASTContext.cpp

@@ -4000,6 +4000,10 @@ SILFunctionType::SILFunctionType(GenericSignature *genericSig, ExtInfo ext,
 
   // Make sure the interface types are sane.
   if (genericSig) {
+    assert(!genericSig->areAllParamsConcrete() &&
+           "If all generic parameters are concrete, SILFunctionType should "
+           "not have a generic signature at all");
+
     for (auto gparam : genericSig->getGenericParams()) {
       (void)gparam;
       assert(gparam->isCanonical() && "generic signature is not canonicalized");

lib/IRGen/GenProto.cpp

@@ -3091,7 +3091,7 @@ GenericTypeRequirements::GenericTypeRequirements(IRGenModule &IGM,
   // We only need to do something here if the declaration context is
   // somehow generic.
   auto ncGenerics = typeDecl->getGenericSignatureOfContext();
-  if (!ncGenerics) return;
+  if (!ncGenerics || ncGenerics->areAllParamsConcrete()) return;
 
   // Construct a representative function type.
   auto generics = ncGenerics->getCanonicalSignature();