"RealSrcLoc SrcLoc \"filename\" 1 3"
"RealSrcLoc SrcLoc \"filename\" 1 5"
"UnhelpfulLoc \"bad loc\""
"RealSrcSpan SrcSpanPoint \"filename\" 1 3"
"RealSrcSpan SrcSpanOneLine \"filename\" 1 3 5"
"RealSrcSpan SrcSpanMultiLine \"filename\" 1 5 10 1"
"UnhelpfulSpan \"bad span\""