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| author | Simon Peyton Jones <simonpj@microsoft.com> | 2018-10-03 13:27:06 +0100 |
|---|---|---|
| committer | Simon Peyton Jones <simonpj@microsoft.com> | 2018-10-04 15:37:58 +0100 |
| commit | 43c2ffe7c0ce85a8e1305cea3be453fd01de5b63 (patch) | |
| tree | d4f7917e61edadb04ebd728c0c102417dc9aecd8 | |
| parent | e9e664022af66778bcc08f66ce3ba3b012c77ea4 (diff) | |
| download | haskell-43c2ffe7c0ce85a8e1305cea3be453fd01de5b63.tar.gz | |
Better comments and debug-print only
| -rw-r--r-- | compiler/typecheck/TcRnMonad.hs | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/compiler/typecheck/TcRnMonad.hs b/compiler/typecheck/TcRnMonad.hs index aa95c1eb2e..940e6a93ad 100644 --- a/compiler/typecheck/TcRnMonad.hs +++ b/compiler/typecheck/TcRnMonad.hs @@ -954,6 +954,8 @@ reportWarning reason err try_m :: TcRn r -> TcRn (Either IOEnvFailure r) -- Does tryM, with a debug-trace on failure +-- If we do recover from an exception, /insoluble/ constraints +-- (only) in 'thing' are are propagated try_m thing = do { (mb_r, lie) <- tryCaptureConstraints thing ; emitConstraints lie @@ -961,7 +963,7 @@ try_m thing -- Debug trace ; case mb_r of Left exn -> traceTc "tryTc/recoverM recovering from" $ - text (showException exn) + (text (showException exn) $$ ppr lie) Right {} -> return () ; return mb_r } @@ -972,6 +974,8 @@ recoverM :: TcRn r -- Recovery action; do this if the main one fails -- if it generates errors, propagate them all -> TcRn r -- Errors in 'thing' are retained +-- If we do recover from an exception, /insoluble/ constraints +-- (only) in 'thing' are are propagated recoverM recover thing = do { mb_res <- try_m thing ; case mb_res of @@ -1483,7 +1487,7 @@ tryCaptureConstraints :: TcM a -> TcM (Either IOEnvFailure a, WantedConstraints) -- (captureConstraints_maybe m) runs m, -- and returns the type constraints it generates -- It never throws an exception; instead if thing_inside fails, --- it returns Left exn and the insoluble constraints +-- it returns Left exn and the /insoluble/ constraints tryCaptureConstraints thing_inside = do { lie_var <- newTcRef emptyWC ; mb_res <- tryM $ |