Dear GHC hackers, On our work on the new front-end AST for GHC [0] based on TTG [1], we would like to use a pattern synonym like the following [2]: {{{ pattern LL :: HasSrcSpan a => SrcSpan -> SrcSpanLess a -> a pattern LL s m <- (decomposeSrcSpan -> (m , s)) where LL s m = composeSrcSpan (m , s) }}} We know that any match on `LL` patterns, makes the pattern matching total, as it uses a view pattern with a total output pattern (i.e., in `decomposeSrcSpan -> (m , s)`, the pattern `(m , s)` is total). As far as I understand, currently COMPLETE pragmas cannot be used with such a polymorphic pattern. What do you suggest us to do to avoid the false incomplete pattern matching warnings? Thanks, Shayan [0] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow [1] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/TreesThatGro... [2] https://ghc.haskell.org/trac/ghc/wiki/ImplementingTreesThatGrow/HandlingSour...