diff --git a/src/Compiler/AbstractIL/ilread.fs b/src/Compiler/AbstractIL/ilread.fs
index 0ccdd9cf35c..4cacdafc9ed 100644
--- a/src/Compiler/AbstractIL/ilread.fs
+++ b/src/Compiler/AbstractIL/ilread.fs
@@ -1141,6 +1141,7 @@ type ILMetadataReader =
         seekReadMemberRefAsFieldSpec: MemberRefAsFspecIdx -> ILFieldSpec
         seekReadCustomAttr: CustomAttrIdx -> ILAttribute
         seekReadTypeRef: int -> ILTypeRef
+        seekReadTypeDefAsTypeRef: int -> ILTypeRef
         seekReadTypeRefAsType: TypeRefAsTypIdx -> ILType
         readBlobHeapAsPropertySig: BlobAsPropSigIdx -> ILThisConvention * ILType * ILTypes
         readBlobHeapAsFieldSig: BlobAsFieldSigIdx -> ILType
@@ -2334,7 +2335,10 @@ and seekReadTypeDefAsTypeUncached ctxtH (TypeDefAsTypIdx(boxity, ginst, idx)) =
     let ctxt = getHole ctxtH
     mkILTy boxity (ILTypeSpec.Create(seekReadTypeDefAsTypeRef ctxt idx, ginst))
 
-and seekReadTypeDefAsTypeRef (ctxt: ILMetadataReader) idx =
+and seekReadTypeDefAsTypeRef (ctxt: ILMetadataReader) idx = ctxt.seekReadTypeDefAsTypeRef idx
+
+and seekReadTypeDefAsTypeRefUncached ctxtH idx =
+    let (ctxt: ILMetadataReader) = getHole ctxtH
     let mdv = ctxt.mdfile.GetView()
 
     let enc =
@@ -4504,6 +4508,9 @@ let openMetadataReader
     let cacheTypeDefAsType =
         mkCacheGeneric reduceMemoryUsage inbase "TypeDefAsType" (getNumRows TableNames.TypeDef / 20 + 1)
 
+    let cacheTypeDefAsTypeRef =
+        mkCacheGeneric false inbase "TypeDefAsTypeRef" 0
+
     let cacheMethodDefAsMethodData =
         mkCacheGeneric reduceMemoryUsage inbase "MethodDefAsMethodData" (getNumRows TableNames.Method / 20 + 1)
 
@@ -4575,6 +4582,7 @@ let openMetadataReader
             seekReadMemberRefAsFieldSpec = seekReadMemberRefAsFieldSpecUncached ctxtH
             seekReadCustomAttr = cacheCustomAttr (seekReadCustomAttrUncached ctxtH)
             seekReadTypeRef = cacheTypeRef (seekReadTypeRefUncached ctxtH)
+            seekReadTypeDefAsTypeRef = cacheTypeDefAsTypeRef (seekReadTypeDefAsTypeRefUncached ctxtH)
             readBlobHeapAsPropertySig = cacheBlobHeapAsPropertySig (readBlobHeapAsPropertySigUncached ctxtH)
             readBlobHeapAsFieldSig = cacheBlobHeapAsFieldSig (readBlobHeapAsFieldSigUncached ctxtH)
             readBlobHeapAsMethodSig = cacheBlobHeapAsMethodSig (readBlobHeapAsMethodSigUncached ctxtH)