diff --git a/src/Compiler/TypedTree/TypedTreeOps.fs b/src/Compiler/TypedTree/TypedTreeOps.fs
index fe25b787944..96c1e91e193 100644
--- a/src/Compiler/TypedTree/TypedTreeOps.fs
+++ b/src/Compiler/TypedTree/TypedTreeOps.fs
@@ -5869,10 +5869,14 @@ let remapAttribKind tmenv k =
     | ILAttrib _ as x -> x
     | FSAttrib vref -> FSAttrib(remapValRef tmenv vref)
 
-let tmenvCopyRemapAndBindTypars remapAttrib tmenv tps = 
-    let tps', tyenvinner = copyAndRemapAndBindTyparsFull remapAttrib tmenv tps
-    let tmenvinner = tyenvinner 
-    tps', tmenvinner
+let tmenvCopyRemapAndBindTypars remapAttrib tmenv tps =
+    match tmenv.realsig with
+    | false ->
+        let tps', tyenvinner = copyAndRemapAndBindTyparsFull remapAttrib tmenv tps
+        let tmenvinner = tyenvinner 
+        tps', tmenvinner
+    | true ->
+        tps, tmenv
 
 type RemapContext =
     { g: TcGlobals