TYPE SIGNATURES somethingShowable :: Show Bool => Bool -> String Dependent modules: [] Dependent packages: [base-4.13.0.0, ghc-bignum-1.0, ghc-prim-0.6.1] SomethingShowable.hs:5:1: warning: [-Wsimplifiable-class-constraints (in -Wdefault)] • The constraint ‘Show Bool’ matches instance Show Bool -- Defined in ‘GHC.Show’ This makes type inference for inner bindings fragile; either use MonoLocalBinds, or simplify it using the instance • When checking the inferred type somethingShowable :: Show Bool => Bool -> String