From 4d5984258731e82c17535cbe9c257cf639374151 Mon Sep 17 00:00:00 2001 From: herbelin Date: Sun, 28 Jan 2007 13:32:56 +0000 Subject: Pas de solution à court terme pour ce problème de complexité MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9548 85f007b7-540e-0410-9357-904b9bb8a0f7 --- test-suite/ideal-features/evars_subst.v | 53 +++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) create mode 100644 test-suite/ideal-features/evars_subst.v (limited to 'test-suite/ideal-features') diff --git a/test-suite/ideal-features/evars_subst.v b/test-suite/ideal-features/evars_subst.v new file mode 100644 index 000000000..6f9f86a95 --- /dev/null +++ b/test-suite/ideal-features/evars_subst.v @@ -0,0 +1,53 @@ +(* Bug report #932 *) +(* Expected time < 1.00s *) + +(* Let n be the number of let-in. The complexity comes from the fact + that each implicit arguments of f was in a larger and larger + context. To compute the type of "let _ := f ?Tn 0 in f ?T 0", + "f ?Tn 0" is substituted in the type of "f ?T 0" which is ?T. This + type is an evar instantiated on the n variables denoting the "f ?Ti 0". + One obtain "?T[1;...;n-1;f ?Tn[1;...;n-1] 0]". To compute the + type of "let _ := f ?Tn-1 0 in let _ := f ?Tn 0 in f ?T 0", another + substitution is done leading to + "?T[1;...;n-2;f ?Tn[1;...;n-2] 0;f ?Tn[1;...;n-2;f ?Tn[1;...;n-2] 0] 0]" + and so on. At the end, we get a term of exponential size *) + +(* A way to cut the complexity could have been to remove the dependency in + anonymous variables in evars but this breaks intuitive behaviour + (see Case15.v); another approach could be to substitute lazily + and/or to simultaneously substitute let binders and evars *) + +Variable P : Set -> Set. +Variable f : forall A : Set, A -> P A. + +Time Check + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + let _ := f _ 0 in + + f _ 0. + -- cgit v1.2.3