Resolving dependencies...
Downloading weighted-regexp-0.3.1.2...
Configuring weighted-regexp-0.3.1.2...
Building weighted-regexp-0.3.1.2...
Preprocessing library weighted-regexp-0.3.1.2...

dist/build/Text/RegExp/Parser.hs:2:12: Warning:
    -fglasgow-exts is deprecated: Use individual extensions instead
[ 1 of 13] Compiling Data.Semiring    ( src/Data/Semiring.hs, dist/build/Data/Semiring.o )

src/Data/Semiring.hs:85:10:
    Could not deduce (Eq a)
      arising from the superclasses of an instance declaration
    from the context (Num a)
      bound by the instance declaration at src/Data/Semiring.hs:85:10-38
    Possible fix: add (Eq a) to the context of the instance declaration
    In the instance declaration for `Semiring (Numeric a)'
Failed to install weighted-regexp-0.3.1.2
cabal: Error: some packages failed to install:
weighted-regexp-0.3.1.2 failed during the building phase. The exception was:
ExitFailure 1