private ImmutableArray <SourceText> GetSources(CompilationOptionsReader pdbReader, Encoding encoding)
{
var builder = ImmutableArray.CreateBuilder <SourceText>();
foreach (var srcFile in pdbReader.GetSourceFileNames())
{
var text = _sourceResolver.ResolveSource(srcFile, encoding);
builder.Add(text);
}
return(builder.ToImmutable());
}