diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenOverridingAndHiding.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenOverridingAndHiding.cs
index ce2d5cba3a279..e013c7f76c9a1 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenOverridingAndHiding.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenOverridingAndHiding.cs
@@ -1190,8 +1190,9 @@ static void Main()
                     };
 
                     var substitutedSource = subst(substitutedSource0);
-                    var compilation = CreateCompilation(substitutedSource, options: TestOptions.ReleaseExe);
+                    var compilation = CreateCompilation(substitutedSource, options: TestOptions.ReleaseExe, targetFramework: TargetFramework.StandardLatest);
                     string expectedOutput;
+                    Assert.Equal(RuntimeUtilities.IsCoreClrRuntime, compilation.Assembly.RuntimeSupportsCovariantReturnsOfClasses);
                     if (compilation.Assembly.RuntimeSupportsCovariantReturnsOfClasses)
                     {
                         // Correct runtime behavior with no warning
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/InheritanceBindingTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/InheritanceBindingTests.cs
index 0c28203a20a49..46544f147fa73 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/InheritanceBindingTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/InheritanceBindingTests.cs
@@ -4937,7 +4937,8 @@ public class Derived : Base<short, int>
     public override void Method(short s, int i) { }
 }
 ";
-            CSharpCompilation comp = CreateCompilation(text);
+            CSharpCompilation comp = CreateCompilation(text, targetFramework: TargetFramework.StandardLatest);
+            Assert.Equal(RuntimeUtilities.IsCoreClrRuntime, comp.Assembly.RuntimeSupportsCovariantReturnsOfClasses);
             if (comp.Assembly.RuntimeSupportsDefaultInterfaceImplementation)
             {
                 comp.VerifyDiagnostics(
@@ -4995,7 +4996,8 @@ class Derived : Base<int>
     public override void Method(int @in, ref int @ref) { }
 }
 ";
-            var compilation = CreateCompilation(text);
+            var compilation = CreateCompilation(text, targetFramework: TargetFramework.StandardLatest);
+            Assert.Equal(RuntimeUtilities.IsCoreClrRuntime, compilation.Assembly.RuntimeSupportsCovariantReturnsOfClasses);
             if (compilation.Assembly.RuntimeSupportsCovariantReturnsOfClasses)
             {
                 // We no longer report a runtime ambiguous override because the compiler
diff --git a/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs b/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
index 5cce4d6595bdc..3ba22698c6c4b 100644
--- a/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
+++ b/src/Compilers/CSharp/Test/Symbol/Symbols/SymbolErrorTests.cs
@@ -7723,7 +7723,8 @@ class D : C<int>
    public override void F(int t) {}   // CS0462
 }
 ";
-            var comp = CreateCompilation(text);
+            var comp = CreateCompilation(text, targetFramework: TargetFramework.StandardLatest);
+            Assert.Equal(RuntimeUtilities.IsCoreClrRuntime, comp.Assembly.RuntimeSupportsCovariantReturnsOfClasses);
             if (comp.Assembly.RuntimeSupportsDefaultInterfaceImplementation)
             {
                 comp.VerifyDiagnostics(
@@ -18406,7 +18407,8 @@ public override void Test(string s, ref int x) { }
 }
 ";
             // We no longer report a runtime ambiguous override (CS1957) because the compiler produces a methodimpl record to disambiguate.
-            CSharpCompilation comp = CreateCompilation(text);
+            CSharpCompilation comp = CreateCompilation(text, targetFramework: TargetFramework.StandardLatest);
+            Assert.Equal(RuntimeUtilities.IsCoreClrRuntime, comp.Assembly.RuntimeSupportsCovariantReturnsOfClasses);
             if (comp.Assembly.RuntimeSupportsDefaultInterfaceImplementation)
             {
                 comp.VerifyDiagnostics(