diff --git a/Directory.Build.props b/Directory.Build.props
index d00d268a9ea..424258eef47 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -38,7 +38,7 @@
      -->
     <OtherFlags Condition="'$(Configuration)' != 'Proto' and '$(TestingLegacyInternalSignature)' != 'true'">$(OtherFlags) --realsig-</OtherFlags>
     <!-- TBD: Fix MEF Export visibility issues in VS -->
-    <OtherFlags Condition="'$(Configuration)' != 'Proto' and '$(TestingLegacyInternalSignature)' == 'true'">$(OtherFlags) --realsig-</OtherFlags>
+    <OtherFlags Condition="'$(Configuration)' != 'Proto' and '$(TestingLegacyInternalSignature)' == 'true'">$(OtherFlags) --realsig+</OtherFlags>
 
   </PropertyGroup>
 
diff --git a/src/Compiler/Checking/AugmentWithHashCompare.fs b/src/Compiler/Checking/AugmentWithHashCompare.fs
index f34c447f257..4326ac6ccfc 100644
--- a/src/Compiler/Checking/AugmentWithHashCompare.fs
+++ b/src/Compiler/Checking/AugmentWithHashCompare.fs
@@ -1347,7 +1347,10 @@ let MakeValsForEqualsAugmentation g (tcref: TyconRef) =
 
 let MakeValsForEqualityWithComparerAugmentation g (tcref: TyconRef) =
     let _, ty = mkMinimalTy g tcref
-    let vis = tcref.TypeReprAccessibility
+    let vis =
+        // Equality method for union types match the union type visibility rather than the TypeReprAccessibility
+        if tcref.IsUnionTycon then tcref.Accessibility
+        else tcref.TypeReprAccessibility
     let tps = tcref.Typars tcref.Range
 
     let objGetHashCodeVal =
diff --git a/tests/FSharp.Compiler.ComponentTests/EmittedIL/CCtorDUWithMember/CCtorDUWithMember.fs b/tests/FSharp.Compiler.ComponentTests/EmittedIL/CCtorDUWithMember/CCtorDUWithMember.fs
index 99c31471aba..248532a1638 100644
--- a/tests/FSharp.Compiler.ComponentTests/EmittedIL/CCtorDUWithMember/CCtorDUWithMember.fs
+++ b/tests/FSharp.Compiler.ComponentTests/EmittedIL/CCtorDUWithMember/CCtorDUWithMember.fs
@@ -80,3 +80,69 @@ module CCtorDUWithMember =
         |> asFs
         |> withAdditionalSourceFile (SourceFromPath (__SOURCE_DIRECTORY__ ++ "CCtorDUWithMember04.fs"))
         |> verifyCompilation 
+
+    let withRealInternalSignature realSig compilation =
+        compilation
+        |> withOptions [if realSig then "--realsig+" else "--realsig-" ]
+
+    [<InlineData(true)>]        // RealSig
+    [<InlineData(false)>]       // Regular
+    [<Theory>]
+    let ``public - DU internal case specified in fsi file`` (realSig) =
+        Fsi """
+namespace RealInternalSignature
+
+[<StructuralEquality; StructuralComparison>]
+type ILArrayShape =
+    internal 
+    | One
+"""
+        |> withAdditionalSourceFile (FsSource ("""
+namespace RealInternalSignature
+
+[<StructuralEquality; StructuralComparison>]
+type ILArrayShape =
+    | One
+        """))
+        |> asLibrary
+        |> withLangVersionPreview
+        |> withRealInternalSignature realSig
+        |> compile
+        |> withILContains [
+            """
+  .method public hidebysig instance bool 
+          Equals(class RealInternalSignature.ILArrayShape obj,
+                 class [runtime]System.Collections.IEqualityComparer comp) cil managed
+  {
+    .custom instance void [runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 ) 
+"""
+            ]
+        |> shouldSucceed
+
+    [<InlineData(true)>]        // RealSig
+    [<InlineData(false)>]       // Regular
+    [<Theory>]
+    let ``public - DU internal case specified in fs file`` (realSig) =
+        FSharp """
+namespace RealInternalSignature
+
+[<StructuralEquality; StructuralComparison>]
+type ILArrayShape =
+    internal 
+    | One
+"""
+        |> asLibrary
+        |> withLangVersionPreview
+        |> withRealInternalSignature realSig
+        |> compile
+        |> withILContains [
+            """
+  .method public hidebysig instance bool 
+          Equals(class RealInternalSignature.ILArrayShape obj,
+                 class [runtime]System.Collections.IEqualityComparer comp) cil managed
+  {
+    .custom instance void [runtime]System.Runtime.CompilerServices.CompilerGeneratedAttribute::.ctor() = ( 01 00 00 00 ) 
+"""
+            ]
+        |> shouldSucceed
+
diff --git a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
index b37d8e1b528..909e42e2cdc 100644
--- a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
+++ b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.debug.bsl
@@ -51,6 +51,7 @@ FSharp.Compiler.AbstractIL.IL+ILArgConvention: Int32 Tag
 FSharp.Compiler.AbstractIL.IL+ILArgConvention: Int32 get_Tag()
 FSharp.Compiler.AbstractIL.IL+ILArgConvention: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(ILArrayShape)
+FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(ILArrayShape, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: ILArrayShape FromRank(Int32)
@@ -65,6 +66,7 @@ FSharp.Compiler.AbstractIL.IL+ILArrayShape: Int32 Rank
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Int32 get_Rank()
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(ILAssemblyLongevity)
+FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(ILAssemblyLongevity, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: ILAssemblyLongevity Default
@@ -950,6 +952,7 @@ FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String Name
 FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String get_Name()
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(ILNativeResource)
+FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(ILNativeResource, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Int32 CompareTo(ILNativeResource)
@@ -1224,6 +1227,7 @@ FSharp.Compiler.AbstractIL.IL+ILParameter: Microsoft.FSharp.Core.FSharpOption`1[
 FSharp.Compiler.AbstractIL.IL+ILParameter: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILParameter: Void .ctor(Microsoft.FSharp.Core.FSharpOption`1[System.String], ILType, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.AbstractIL.IL+ILFieldInit], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.AbstractIL.IL+ILNativeType], Boolean, Boolean, Boolean, ILAttributesStored, Int32)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(ILPlatform)
+FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(ILPlatform, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Int32 CompareTo(ILPlatform)
@@ -2286,6 +2290,7 @@ FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String FileName
 FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String ToString()
 FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String get_FileName()
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet)
+FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet, System.Collections.IEqualityComparer)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(System.Object)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Int32 GetHashCode()
diff --git a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
index b37d8e1b528..909e42e2cdc 100644
--- a/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
+++ b/tests/FSharp.Compiler.Service.Tests/FSharp.Compiler.Service.SurfaceArea.netstandard20.release.bsl
@@ -51,6 +51,7 @@ FSharp.Compiler.AbstractIL.IL+ILArgConvention: Int32 Tag
 FSharp.Compiler.AbstractIL.IL+ILArgConvention: Int32 get_Tag()
 FSharp.Compiler.AbstractIL.IL+ILArgConvention: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(ILArrayShape)
+FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(ILArrayShape, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: ILArrayShape FromRank(Int32)
@@ -65,6 +66,7 @@ FSharp.Compiler.AbstractIL.IL+ILArrayShape: Int32 Rank
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: Int32 get_Rank()
 FSharp.Compiler.AbstractIL.IL+ILArrayShape: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(ILAssemblyLongevity)
+FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(ILAssemblyLongevity, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILAssemblyLongevity: ILAssemblyLongevity Default
@@ -950,6 +952,7 @@ FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String Name
 FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILModuleRef: System.String get_Name()
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(ILNativeResource)
+FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(ILNativeResource, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILNativeResource: Int32 CompareTo(ILNativeResource)
@@ -1224,6 +1227,7 @@ FSharp.Compiler.AbstractIL.IL+ILParameter: Microsoft.FSharp.Core.FSharpOption`1[
 FSharp.Compiler.AbstractIL.IL+ILParameter: System.String ToString()
 FSharp.Compiler.AbstractIL.IL+ILParameter: Void .ctor(Microsoft.FSharp.Core.FSharpOption`1[System.String], ILType, Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.AbstractIL.IL+ILFieldInit], Microsoft.FSharp.Core.FSharpOption`1[FSharp.Compiler.AbstractIL.IL+ILNativeType], Boolean, Boolean, Boolean, ILAttributesStored, Int32)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(ILPlatform)
+FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(ILPlatform, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(System.Object)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.AbstractIL.IL+ILPlatform: Int32 CompareTo(ILPlatform)
@@ -2286,6 +2290,7 @@ FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String FileName
 FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String ToString()
 FSharp.Compiler.CodeAnalysis.FSharpSymbolUse: System.String get_FileName()
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet)
+FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet, System.Collections.IEqualityComparer)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(System.Object)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Boolean Equals(System.Object, System.Collections.IEqualityComparer)
 FSharp.Compiler.CodeAnalysis.FSharpUnresolvedReferencesSet: Int32 GetHashCode()
diff --git a/tests/FSharp.Compiler.Service.Tests/SurfaceArea.fs b/tests/FSharp.Compiler.Service.Tests/SurfaceArea.fs
index 2e09e6cc65d..85ac86b3f33 100644
--- a/tests/FSharp.Compiler.Service.Tests/SurfaceArea.fs
+++ b/tests/FSharp.Compiler.Service.Tests/SurfaceArea.fs
@@ -35,9 +35,4 @@ type SurfaceAreaTest() =
 
         let baseline = Path.Combine(__SOURCE_DIRECTORY__, $"FSharp.Compiler.Service.SurfaceArea.{platform}.{flavor}.bsl")
         let outFileName = $"FSharp.Compiler.Service.SurfaceArea.{platform}.{flavor}.out"
-
-        let realSig = Environment.GetEnvironmentVariable("FSHARP_REALSIG")
-        match realSig with
-        | "false" -> Assert.True(true, "Skipping the test, the surface area without real sig differs and doesn't matter.")
-        | _ -> FSharp.Test.SurfaceArea.verify assembly baseline outFileName
-
+        FSharp.Test.SurfaceArea.verify assembly baseline outFileName