ASTMangler: Fix conformance path mangling for noncopyable generics

Author: slavapestov

lib/AST/ASTMangler.cpp

@@ -3697,14 +3697,21 @@ static unsigned conformanceRequirementIndex(
     if (req.getKind() != RequirementKind::Conformance)
       continue;
 
+    // This is an ABI compatibility hack for noncopyable generics.
+    // We should have really been skipping marker protocols here all along,
+    // but it's too late now, so skip Copyable and Escapable specifically.
+    if (req.getProtocolDecl()->getInvertibleProtocolKind())
+      continue;
+
     if (req.getFirstType()->isEqual(entry.first) &&
         req.getProtocolDecl() == entry.second)
       return result;
 
     ++result;
   }
 
-  llvm_unreachable("Conformance access path step is missing from requirements");
+  llvm::errs() <<"Conformance access path step is missing from requirements";
+  abort();
 }
 
 void ASTMangler::appendDependentProtocolConformance(

test/SILGen/mangle_conformance_access_path.swift

@@ -2,8 +2,6 @@
 // RUN: %target-swift-frontend -emit-module %S/Inputs/mangle_conformance_access_path_helper.swift -emit-module-path %t/mangle_conformance_access_path_helper.swiftmodule
 // RUN: %target-swift-frontend -emit-silgen %s -I %t | %FileCheck %s
 
-// XFAIL: noncopyable_generics
-
 import mangle_conformance_access_path_helper
 
 struct GG<T : P> {}