Fix bug in Mtype.strengthen_lazy causing spurious typing errors#11776
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gasche merged 3 commits intoocaml:trunkfrom Dec 1, 2022
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Fix bug in Mtype.strengthen_lazy causing spurious typing errors#11776gasche merged 3 commits intoocaml:trunkfrom
Mtype.strengthen_lazy causing spurious typing errors#11776gasche merged 3 commits intoocaml:trunkfrom
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gasche
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I agree that the change looks correct and is consistent with the rest of the code. Approved.
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Merged, thanks! |
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a09392d Set Menhir version back to 20210419 again (ocaml#89) cc63992 Merge pull request ocaml#88 from mshinwell/flambda-backend-changes-2022-12-27 3e49df3 HACKING.jst.adoc 1866676 Merge flambda-backend changes e012992 Merge pull request ocaml#87 from mshinwell/merge-4.14.1 ac5c7c8 Merge tag '4.14.1' into main 3da21bc add a useful debug printer 83b7c72 Document the debug_printers script 98896e0 Remove a tiny code stutter I came across 99cb5d9 release 4.14.1 b49060f last commit before tagging 4.14.1 fae9aef Add documentation 708e5a9 Add tests c609eee Bootstrap 7f922d0 Polymorphic parameters 51aeb04 Keep generalized structure from patterns when typing let 4b68bb3 Add test of princiaplity from polymorphic type constraints 82c7afe fix wong raise aca252f x86: Force result of Icomp to be in a register (ocaml#11808) 985725b Add dynlink_compilerlibs.mli to .gitignore (ocaml#79) 2b1fa24 Regenerate parser (ocaml#80) 1bb6c79 Merge pull request ocaml#78 from mshinwell/flambda-backend-patches-2022-12-13 9029581 Update otherlibs/dynlink/Makefile 3e4f1b9 Revert toplevel/native/dune to ocaml-jst version 6061e4c Regenerate configure using autoconf 2.71 888d4b1 Back out patch which disables alloc-check in ocaml-jst a6d5796 Fix dynlink build 3e46daf Update .depend files a5c547e Bootstrap a6a9031 Merge flambda-backend changes 0ac7fdd temp fix for linker error (ocaml#77) 1018602 Remove references to 32-bit Cygwin (ocaml#11797) e2d0d9e Enable individual testing with Makefile.jst (ocaml#76) f10cbf6 increment version number after tagging 4.14.1~rc1 11c5ab7 release 4.14.1~rc1 e4c3920 last commit before tagging 4.14.1~rc1 9e598ca Merge pull request ocaml#11793 from dra27/then-than 2a7e501 Use a more relaxed mode for unification in Ctype.subst (ocaml#11771) (ocaml#73) 7b35ef7 Statically initialize `caml_global_data` with a valid value (ocaml#11788) cbd791a Allow immediates to cross modes (ocaml#58) 85a0817 Merge pull request ocaml#11534 from gasche/follow-synonyms-in-show-module-type 699f43c Changes e54e9bc fix the 'stuttering' issue in #show d9799d3 test comments fec3b23 follow synonyms when #show-ing module types 06a1ad7 regression tests for ocaml#11533 (still failing) 549d757 Run "misplaced attributes" check when compiling mlis (ocaml#72) b2b74bf Fix bug in `Mtype.strengthen_lazy` causing spurious typing errors (ocaml#11776) a6c0e75 Ensure that Ctype.nongen always calls remove_mode_variables (ocaml#70) 6c50831 array elements are global (ocaml#67) bc510ed Ensure that types from packed modules are always generalised (ocaml#11732) 4d47036 Fix ocaml#10768 8788ff6 Add/move some documentation 9891a36 Propagate location information to `local_` in expressions 988306d Add support for `global_` and `nonlocal_` constructor arguments (ocaml#50) 6729eb8 Missing CAMLparam in win32's Unix.stat (ocaml#11737) e7dd740 Add debug_printers.ml (ocaml#63) 65f2896 more entries in gitignore (ocaml#62) a9a84d0 Move `global_flag` to `Asttypes` (ocaml#60) fac5896 Minor attribute fixes from flambda-backend 75f402e Note about make install and Makefile.jst (ocaml#56) fb5b1e4 Remove the -force-tmc flag (ocaml#11661) bd87a61 ocamlmklib: use `ar rcs` instead of `ar rc` (ocaml#11670) 83762af Merge pull request ocaml#11622 from Octachron/fix_recursive_types_in_constructor_mismatch ca48730 Merge pull request ocaml#11609 from Octachron/pr11194_unbound_and_printing_context git-subtree-dir: ocaml git-subtree-split: a09392d
ejgallego
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…aml#11776) (cherry picked from commit 4243c4b)
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This fixes a bug in
strengthen_lazy.The bug is that, when recursing on the result type of a functor with a named parameter,
strengthen_lazydidn't add this parameter to the environment. In most cases this doesn't matter, but the added test case shows a program that 4.14 rejects incorrectly as a result:Here,
M5is given a less precise type than it could be, because aNot_foundexception is raised during strengthening due to the module that's missing from the env. As a result,t's type is also less precise (losing the connection toM2that would have come from strengthening), and the module inclusion comparingM4's body to its result type fails (incorrectly).In this case, the
Not_foundexception is raised by the shape computation incomponents_of_functor_appl, which expects to be able to compute the shape of a functor argument. So this program fails on 4.14 but checks on 4.12, before the shape system was added. But I don't think the bug is actually related to the shape system, and suspect it could be triggered pre-shapes by a more complex example.Credit to @lukemaurer for noticing the bug and constructing the test case.