#12957: In a record-update construct:ghc-stage2: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: niteria | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by niteria): {{{ diff --git a/compiler/hsSyn/HsExpr.hs b/compiler/hsSyn/HsExpr.hs index 78ee4e0..4422ec7 100644 --- a/compiler/hsSyn/HsExpr.hs +++ b/compiler/hsSyn/HsExpr.hs @@ -2389,7 +2389,7 @@ matchSeparator LambdaExpr = text "->" matchSeparator ProcExpr = text "->" matchSeparator PatBindRhs = text "=" matchSeparator (StmtCtxt _) = text "<-" -matchSeparator RecUpd = panic "unused" +matchSeparator RecUpd = text "{" matchSeparator ThPatSplice = panic "unused" matchSeparator ThPatQuote = panic "unused" matchSeparator PatSyn = panic "unused" }}} makes the panic go away, but the error isn't very nice: {{{ [1 of 1] Compiling Repro ( Repro.hs, Repro.o ) Repro.hs:22:35: warning: [-Woverlapping-patterns] Pattern match has inaccessible right hand side In a record-update construct: BFields ds_dFp { ... }}} -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/12957#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler