Merge pull request swiftlang#72561 from xymus/harden-deser

Serialization: Harden recovery from broken deserialization context

Author: xymus

lib/Serialization/Deserialization.cpp

@@ -873,7 +873,11 @@ ProtocolConformanceDeserializer::readInheritedProtocolConformance(
   InheritedProtocolConformanceLayout::readRecord(scratch, conformanceID,
                                                  conformingTypeID);
 
-  Type conformingType = MF.getType(conformingTypeID);
+  auto conformingTypeOrError =
+    MF.getTypeChecked(conformingTypeID);
+  if (!conformingTypeOrError)
+    return conformingTypeOrError.takeError();
+  Type conformingType = conformingTypeOrError.get();
 
   PrettyStackTraceType trace(ctx, "reading inherited conformance for",
                              conformingType);
@@ -3465,7 +3469,10 @@ class DeclDeserializer {
       }
     }
 
-    auto DC = MF.getDeclContext(contextID);
+    auto DCOrError = MF.getDeclContextChecked(contextID);
+    if (!DCOrError)
+      return DCOrError.takeError();
+    auto DC = DCOrError.get();
     if (declOrOffset.isComplete())
       return declOrOffset;
 
@@ -3806,14 +3813,22 @@ class DeclDeserializer {
       AddAttribute(new (ctx) HasStorageAttr(/*isImplicit:*/true));
 
     if (opaqueReturnTypeID) {
+      auto opaqueReturnType = MF.getDeclChecked(opaqueReturnTypeID);
+      if (!opaqueReturnType)
+        return opaqueReturnType.takeError();
+
       ctx.evaluator.cacheOutput(
           OpaqueResultTypeRequest{var},
-          cast<OpaqueTypeDecl>(MF.getDecl(opaqueReturnTypeID)));
+          cast<OpaqueTypeDecl>(opaqueReturnType.get()));
     }
 
     // If this is a lazy property, record its backing storage.
     if (lazyStorageID) {
-      VarDecl *storage = cast<VarDecl>(MF.getDecl(lazyStorageID));
+      auto lazyStorageDecl = MF.getDeclChecked(lazyStorageID);
+      if (!lazyStorageDecl)
+        return lazyStorageDecl.takeError();
+
+      VarDecl *storage = cast<VarDecl>(lazyStorageDecl.get());
       ctx.evaluator.cacheOutput(
           LazyStoragePropertyRequest{var}, std::move(storage));
     }