Fix corner case of useless constraint in SPECIALISE pragma

[ghc-hetmet.git] / compiler / typecheck / TcInstDcls.lhs

diff --git a/compiler/typecheck/TcInstDcls.lhs b/compiler/typecheck/TcInstDcls.lhs
index b4d3498..9ef0376 100644 (file)
--- a/compiler/typecheck/TcInstDcls.lhs
+++ b/compiler/typecheck/TcInstDcls.lhs
@@ -582,10 +582,11 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags })
        dfun_id    = instanceDFunId ispec
        rigid_info = InstSkol
        inst_ty    = idType dfun_id
+       loc        = srcLocSpan (getSrcLoc dfun_id)
     in
         -- Prime error recovery
     recoverM (returnM emptyLHsBinds)           $
-    setSrcSpan (srcLocSpan (getSrcLoc dfun_id))        $
+    setSrcSpan loc                             $
     addErrCtxt (instDeclCtxt2 (idType dfun_id))        $
 
        -- Instantiate the instance decl with skolem constants 
@@ -638,7 +639,7 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = VanillaInst monobinds uprags })
        scs_and_meths = map instToId sc_dicts ++ meth_ids
        this_dict_id  = instToId this_dict
        inline_prag | null dfun_arg_dicts = []
-                   | otherwise = [InlinePrag (Inline AlwaysActive True)]
+                   | otherwise = [L loc (InlinePrag (Inline AlwaysActive True))]
                -- Always inline the dfun; this is an experimental decision
                -- because it makes a big performance difference sometimes.
                -- Often it means we can do the method selection, and then