[project @ 2005-02-25 13:54:41 by simonpj]

Prevent a crash; reason the situation arises in the first place is still unclear

diff --git a/ghc/compiler/typecheck/TcSimplify.lhs b/ghc/compiler/typecheck/TcSimplify.lhs
index dd4d215..5db9c0a 100644 (file)
--- a/ghc/compiler/typecheck/TcSimplify.lhs
+++ b/ghc/compiler/typecheck/TcSimplify.lhs
@@ -2394,7 +2394,8 @@ addNoInstanceErrs mb_what givens dicts
                -- Insts for which it is worth suggesting an adding an instance declaration
                -- Exclude implicit parameters, and tyvar dicts
 
-       add_ors :: [SDoc] -> [SDoc]
+       add_ors :: [SDoc] -> [SDoc]     -- The empty case should not happen
+       add_ors []      = ptext SLIT("[No suggested fixes]")    -- Strange
        add_ors (f1:fs) = f1 : map (ptext SLIT("or") <+>) fs
 
 addTopAmbigErrs dicts