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| author | Richard Eisenberg <eir@cis.upenn.edu> | 2015-03-23 10:30:19 -0400 |
|---|---|---|
| committer | Richard Eisenberg <eir@cis.upenn.edu> | 2015-03-23 12:26:35 -0400 |
| commit | c1edbdfd9148ad9f74bfe41e76c524f3e775aaaa (patch) | |
| tree | 001ba874b4a2e324556c95a76accec7b750879dd /compiler/main/Constants.hs | |
| parent | 0f03a843e7e740218f3ce3853f80de99b0ed6236 (diff) | |
| download | haskell-c1edbdfd9148ad9f74bfe41e76c524f3e775aaaa.tar.gz | |
Do proper depth checking in the flattener to avoid looping.
This implements (roughly) the plan put forward in comment:14:ticket:7788,
fixing #7788, #8550, #9554, #10139, and addressing concerns raised in #10079.
There are some regressions w.r.t. GHC 7.8, but only with pathological type
families (like F a = F a). This also (hopefully -- don't have a test case)
fixes #10158. Unsolved problems include #10184 and #10185, which are both
known deficiencies of the approach used here.
As part of this change, the plumbing around detecting infinite loops has
changed. Instead of -fcontext-stack and -ftype-function-depth, we now have
one combined -freduction-depth parameter. Setting it to 0 disbales the
check, which is now the recommended way to get (terminating) code to
typecheck in releases. (The number of reduction steps may well change between
minor GHC releases!)
This commit also introduces a new IntWithInf type in BasicTypes
that represents an integer+infinity. This type is used in a few
places throughout the code.
Tests in
indexed-types/should_fail/T7788
indexed-types/should_fail/T8550
indexed-types/should_fail/T9554
indexed-types/should_compile/T10079
indexed-types/should_compile/T10139
typecheck/should_compile/T10184 (expected broken)
typecheck/should_compile/T10185 (expected broken)
This commit also changes performance testsuite numbers, for the better.
Diffstat (limited to 'compiler/main/Constants.hs')
| -rw-r--r-- | compiler/main/Constants.hs | 11 |
1 files changed, 4 insertions, 7 deletions
diff --git a/compiler/main/Constants.hs b/compiler/main/Constants.hs index 0054888df3..0f23fc242e 100644 --- a/compiler/main/Constants.hs +++ b/compiler/main/Constants.hs @@ -17,13 +17,10 @@ mAX_TUPLE_SIZE :: Int mAX_TUPLE_SIZE = 62 -- Should really match the number -- of decls in Data.Tuple -mAX_CONTEXT_REDUCTION_DEPTH :: Int -mAX_CONTEXT_REDUCTION_DEPTH = 100 - -- Trac #5395 reports at least one library that needs depth 37 here - -mAX_TYPE_FUNCTION_REDUCTION_DEPTH :: Int -mAX_TYPE_FUNCTION_REDUCTION_DEPTH = 200 - -- Needs to be much higher than mAX_CONTEXT_REDUCTION_DEPTH; see Trac #5395 +-- | Default maximum depth for both class instance search and type family +-- reduction. See also Trac #5395. +mAX_REDUCTION_DEPTH :: Int +mAX_REDUCTION_DEPTH = 200 wORD64_SIZE :: Int wORD64_SIZE = 8 |