From ac15ae397caeec618754fdb04d14f71fa954cfd4 Mon Sep 17 00:00:00 2001
From: herbelin <herbelin@85f007b7-540e-0410-9357-904b9bb8a0f7>
Date: Tue, 12 Dec 2006 09:40:37 +0000
Subject: Test bug #932

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/coq/trunk@9434 85f007b7-540e-0410-9357-904b9bb8a0f7
---
 test-suite/complexity/evars_subst.v | 77 +++++++++++++++++++++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 test-suite/complexity/evars_subst.v

(limited to 'test-suite/complexity')

diff --git a/test-suite/complexity/evars_subst.v b/test-suite/complexity/evars_subst.v
new file mode 100644
index 000000000..58a09dd3f
--- /dev/null
+++ b/test-suite/complexity/evars_subst.v
@@ -0,0 +1,77 @@
+(* 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 is to remove the dependency in
+   anonymous variables in evars; another approach would 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.
+
+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
+  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.
+
-- 
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