diff options
Diffstat (limited to 'compiler/GHC/Tc/Gen/Splice.hs')
| -rw-r--r-- | compiler/GHC/Tc/Gen/Splice.hs | 14 |
1 files changed, 10 insertions, 4 deletions
diff --git a/compiler/GHC/Tc/Gen/Splice.hs b/compiler/GHC/Tc/Gen/Splice.hs index fcd1474afa..13cd3e71c9 100644 --- a/compiler/GHC/Tc/Gen/Splice.hs +++ b/compiler/GHC/Tc/Gen/Splice.hs @@ -754,11 +754,17 @@ tcTopSpliceExpr isTypedSplice tc_action -- is expected (#7276) setStage (Splice isTypedSplice) $ do { -- Typecheck the expression - (expr', wanted) <- captureConstraints tc_action - ; const_binds <- simplifyTop wanted + (mb_expr', wanted) <- tryCaptureConstraints tc_action + -- If tc_action fails (perhaps because of insoluble constraints) + -- we want to capture and report those constraints, else we may + -- just get a silent failure (#20179). Hence the 'try' part. - -- Zonk it and tie the knot of dictionary bindings - ; return $ mkHsDictLet (EvBinds const_binds) expr' } + ; const_binds <- simplifyTop wanted + + ; case mb_expr' of + Nothing -> failM -- In this case simplifyTop should have + -- reported some errors + Just expr' -> return $ mkHsDictLet (EvBinds const_binds) expr' } {- ************************************************************************ |