-fno-monomorphism-restriction != dynamic

Section 4.18 claims -fno-monomorphism-restriction is
dynamic.  ":set"ting it in GHCi seems to have no
affect:

Loading:

> i = 1
> y = (1::Int) + i
> x = 1.1 + i
> main = error "main"

with -fno-monomorphism-restriction :set (but not set
on the command line) gives:

    Prelude> fmap (filter (==
"-fno-monomorphism-restriction")) System.getArgs >>= print
    []
    Prelude> :set -fno-monomorphism-restriction
    Prelude> Compiling Main             (
/home/gunter/haskell/TestMonomorphism.hs, interpreted )
    
    /home/gunter/haskell/TestMonomorphism.hs:3:
        No instance for (Fractional Int)
        arising from the literal `1.1' at
/home/gunter/haskell/TestMonomorphism.hs:3
        In the first argument of `(+)', namely `1.1'
        In the definition of `x': 1.1 + i
    Failed, modules loaded: none.
    Prelude> 
    
whereas with -fno-monomorphism-restriction set on
the command line gives the expected result:

    Prelude> Compiling Main             (
/home/gunter/haskell/TestMonomorphism.hs, interpreted )
    Ok, modules loaded: Main.
    Main> fmap (filter (==
"-fno-monomorphism-restriction")) System.getArgs >>= print
    ["-fno-monomorphism-restriction"]
    Main> x
    2.1
    Main> y
    2

It would be better to make
-fno-monomorphism-restriction dynamic but at least
the documentation should be fixed.

        thanks,
        mike

Trac metadata

Trac field	Value
Version	5.02
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	ResolvedFixed
Component	Compiler
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