#13799: -ddump-splices prints out declarations in the wrong order -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Template Haskell | Version: 8.0.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Debugging | Unknown/Multiple information is incorrect | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by RyanGlScott): More generally, GHC seems to be pretty cavalier in modifying the quasiquoted declarations before pretty-printing them. Here's another example: {{{#!hs {-# LANGUAGE TemplateHaskell #-} {-# LANGUAGE TypeOperators #-} {-# OPTIONS_GHC -ddump-splices #-} module Bug where $([d| infixr 5 :*: data a :*: b = a :*: b |]) }}} {{{ $ /opt/ghc/8.2.1/bin/runghc Bug.hs Bug.hs:(6,3)-(8,6): Splicing declarations [d| infixr 5 :*:_a1pB, :*:_a1pA data a_a1pC :*:_a1pA b_a1pD = a_a1pC :*:_a1pB b_a1pD |] ======> infixr 5 :*:_a4aj infixr 5 :*:_a4ai data (:*:_a4ai) a_a4ak b_a4al = a_a4ak :*:_a4aj b_a4al Bug.hs:6:3: error: Multiple fixity declarations for ‘:*:_a4aj’ also at Bug.hs:(6,3)-(8,6) | 6 | $([d| infixr 5 :*: | ^^^^^^^^^^^^^^^^... }}} Because `(:*:)` is used in both the type and value namespace, GHC seems to be creating //two// `newName`s for `:*:` behind the hood, and changing the data/fixity declarations accordingly. (Notice that the fixity declaration has two identifiers now!) It then proceeds to fail to compile due to #13054, but that's a separate issue. The issue at hand is that `-ddump- splices` is printing out internal details in the quasiquoted `[d| ... |]` declarations, when it really needn't. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/13799#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler