Hi, I'm having a compile issue with multirec TH. Upon investigation, it seems the same problem occurs in the compilation of one of the examples in the multirec distribution: domi@arial:/tmp> wget -q http://hackage.haskell.org/packages/archive/multirec/0.4.1/multirec-0.4.1.ta... domi@arial:/tmp> tar xzf multirec-0.4.1.tar.gz domi@arial:/tmp> cd multirec-0.4.1/examples domi@arial:/tmp/multirec-0.4.1/examples> ghc --make ASTTHUse.hs [1 of 2] Compiling AST ( AST.hs, AST.o ) [2 of 2] Compiling ASTTHUse ( ASTTHUse.hs, ASTTHUse.o ) Loading package ghc-prim ... linking ... done. Loading package integer-gmp ... linking ... done. Loading package base ... linking ... done. Loading package array-0.3.0.0 ... linking ... done. Loading package containers-0.3.0.0 ... linking ... done. Loading package pretty-1.0.1.1 ... linking ... done. Loading package template-haskell ... linking ... done. Loading package multirec-0.4.1 ... linking ... done. ASTTHUse.hs:31:2: GADT pattern match in non-rigid context for `Tag' Probable solution: add a type signature for `to' In the pattern: Tag L C K f0 In the pattern: L Tag L C K f0 In the definition of `to': to Expr L Tag L C K f0 = Const f0 domi@arial:/tmp/multirec-0.4.1/examples> ghc --version The Glorious Glasgow Haskell Compilation System, version 6.12.1 Can you please tell me if this is a known problem and if so, if there is a workaround? Thanks in advance for your help! Dominique