[("tests/examples/Lambda20.hs:1:10: Warning: Collapse lambdas\nFound:\n  \\ (x : xs) -> \\ x -> foo x x\nWhy not:\n  \\ (_ : xs) x -> foo x x\n",[Replace {rtype = Expr, pos = SrcSpan {startLine = 1, startCol = 10, endLine = 1, endCol = 34}, subts = [("body",SrcSpan {startLine = 1, startCol = 27, endLine = 1, endCol = 34}),("a",SrcSpan {startLine = 1, startCol = 11, endLine = 1, endCol = 17}),("b",SrcSpan {startLine = 1, startCol = 22, endLine = 1, endCol = 23})], orig = "\\ a b -> body"}])]