Template.hs:7:1: warning: [-Wsemigroup (in -Wcompat)] Local definition of ‘<>’ clashes with a future Prelude name. This will become an error in a future release. Template.hs:13:3: warning: [-Wnoncanonical-monoid-instances (in -Wdefault, -Wcompat)] Noncanonical ‘(<>) = mappend’ definition detected in the instance declaration for ‘Semigroup S’. Move definition from ‘mappend’ to ‘(<>)’ See also: https://gitlab.haskell.org/ghc/ghc/-/wikis/proposal/semigroup-monoid Template.hs:16:3: warning: [-Wnoncanonical-monoid-instances (in -Wdefault, -Wcompat)] Noncanonical ‘mappend’ definition detected in the instance declaration for ‘Monoid S’. ‘mappend’ will eventually be removed in favour of ‘(<>)’ Either remove definition for ‘mappend’ (recommended) or define as ‘mappend = (<>)’ See also: https://gitlab.haskell.org/ghc/ghc/-/wikis/proposal/semigroup-monoid Template.hs:20:15: warning: [-Wstar-is-type (in -Wall, -Wcompat)] Using ‘*’ (or its Unicode variant) to mean ‘Data.Kind.Type’ relies on the StarIsType extension, which will become deprecated in the future. Suggested fix: Use ‘Type’ from ‘Data.Kind’ instead.