-tc_defaults [DefaultDecl [] locn]
- = returnTc [] -- no defaults
-
-tc_defaults [DefaultDecl mono_tys locn]
- = tcLookupGlobal_maybe numClassName `thenNF_Tc` \ maybe_num ->
+tcDefaults []
+ = getDefaultTys -- No default declaration, so get the
+ -- default types from the envt;
+ -- i.e. use the curent ones
+ -- (the caller will put them back there)
+ -- It's important not to return defaultDefaultTys here (which
+ -- we used to do) because in a TH program, tcDefaults [] is called
+ -- repeatedly, once for each group of declarations between top-level
+ -- splices. We don't want to carefully set the default types in
+ -- one group, only for the next group to ignore them and install
+ -- defaultDefaultTys
+
+tcDefaults [DefaultDecl [] locn]
+ = returnM [] -- Default declaration specifying no types
+
+tcDefaults [DefaultDecl mono_tys locn]
+ = tcLookupGlobal_maybe numClassName `thenM` \ maybe_num ->