Attach the right location to pattern synonym error message (fixes Trac #8841)
Attach the right location to pattern synonym error message (fixes Trac #8841)

(cherry picked from commit 96daafc3305a691590b88c1175a8f45e5d327471)

hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay,lukexi/ghc-7.8-arm64,lukexi/ghc-7.8-arm64,hferreiro/replay,hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay,hferreiro/replay,lukexi/ghc-7.8-arm64,hferreiro/replay