Fix tests

src/Compilers/CSharp/Test/Symbol/Compilation/CompilationAPITests.cs

@@ -146,11 +146,14 @@ public void PerTreeDiagnosticOptionsVsSpecificOptions()
                 CreateImmutableDictionary(("CS0078", ReportDiagnostic.Error)));
 
             var comp2 = CreateCompilation(tree, options: options);
-            // Per-tree options should have precedence over specific diagnostic options
+            // Specific diagnostic options have precedence over per-tree options
             comp2.VerifyDiagnostics(
                 // (1,16): warning CS0414: The field 'C._f' is assigned but its value is never used
                 //  class C { long _f = 0l; }
-                Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, "_f").WithArguments("C._f").WithLocation(1, 16));
+                Diagnostic(ErrorCode.WRN_UnreferencedFieldAssg, "_f").WithArguments("C._f").WithLocation(1, 16),
+                // (1,22): error CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
+                // class C { long _f = 0l; }
+                Diagnostic(ErrorCode.WRN_LowercaseEllSuffix, "l").WithLocation(1, 22).WithWarningAsError(true));
         }
 
         [Fact]

src/Compilers/VisualBasic/Test/Semantic/Compilation/CompilationAPITests.vb

@@ -116,13 +116,8 @@ End Class")
             options = options.WithSyntaxTreeOptionsProvider(
                 new TestSyntaxTreeOptionsProvider(tree, ("BC42024", ReportDiagnostic.Error)))
             Dim comp2 = CreateCompilationWithMscorlib45({tree}, options:=options)
-            ' Tree options should have precedence over specific diagnostic options
-            comp2.AssertTheseDiagnostics(
-                <errors>
-BC42024: Unused local variable: 'x'.
-        Dim x As Integer
-            ~
-                </errors>)
+            ' Specific diagnostic options should have precedence over tree options
+            comp2.AssertNoDiagnostics()
         End Sub
 
         <Fact>