dont special case libraries

src/Compilers/VisualBasic/Portable/CommandLine/VisualBasicCommandLineParser.vb

@@ -1138,7 +1138,7 @@ lVbRuntimePlus:
                 specificDiagnosticOptions(item.Key) = item.Value
             Next
 
-            If Not IsScriptRunner AndAlso Not hasSourceFiles AndAlso managedResources.IsEmpty() AndAlso outputKind.IsApplication Then
+            If Not IsScriptRunner AndAlso Not hasSourceFiles AndAlso managedResources.IsEmpty() Then
                 ' VB displays help when there is nothing specified on the command line
                 If flattenedArgs.Any Then
                     AddDiagnostic(diagnostics, ERRID.ERR_NoSources)

src/Compilers/VisualBasic/Test/CommandLine/CommandLineTests.vb

@@ -1736,12 +1736,12 @@ a.vb
             outWriter = New StringWriter()
             exitCode = New MockVisualBasicCompiler(Nothing, folder.Path, {"/nologo", "/preferreduilang:en", "/t:library", "/recurse:   . ", "/out:abc.dll"}).Run(outWriter, Nothing)
             Assert.Equal(1, exitCode)
-            Assert.Equal("vbc : error BC2014: the value '   .' is invalid for option 'recurse'", outWriter.ToString().Trim().Replace(vbCrLf, "|"))
+            Assert.Equal("vbc : error BC2014: the value '   .' is invalid for option 'recurse'|vbc : error BC2008: no input sources specified", outWriter.ToString().Trim().Replace(vbCrLf, "|"))
 
             outWriter = New StringWriter()
             exitCode = New MockVisualBasicCompiler(Nothing, folder.Path, {"/nologo", "/preferreduilang:en", "/t:library", "/recurse:./.", "/out:abc.dll"}).Run(outWriter, Nothing)
             Assert.Equal(1, exitCode)
-            Assert.Equal("vbc : error BC2014: the value './.' is invalid for option 'recurse'", outWriter.ToString().Trim().Replace(vbCrLf, "|"))
+            Assert.Equal("vbc : error BC2014: the value './.' is invalid for option 'recurse'|vbc : error BC2008: no input sources specified", outWriter.ToString().Trim().Replace(vbCrLf, "|"))
 
             Dim args As VisualBasicCommandLineArguments
             Dim resolvedSourceFiles As String()