From a9745d914c8a156b76a95cbd9f4052ca06b4a55a Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Sat, 17 Oct 2020 21:40:57 +0200
Subject: Fixes #13216 (use of type classes in the return clause of a match).

This was deactivated in fb1c2a017e but it seems useful (e.g. in
contribs containers).

It seems to be useful
---
 pretyping/cases.ml                 | 2 +-
 test-suite/bugs/closed/bug_13216.v | 4 ++++
 2 files changed, 5 insertions(+), 1 deletion(-)
 create mode 100644 test-suite/bugs/closed/bug_13216.v

diff --git a/pretyping/cases.ml b/pretyping/cases.ml
index 4a29db0dcf..5de0745d17 100644
--- a/pretyping/cases.ml
+++ b/pretyping/cases.ml
@@ -298,7 +298,7 @@ let inductive_template env sigma tmloc ind =
             let ty = EConstr.of_constr ty in
             let ty' = substl subst ty in
             let sigma, e =
-              Evarutil.new_evar env ~src:(hole_source n) ~typeclass_candidate:false sigma ty'
+              Evarutil.new_evar env ~src:(hole_source n) sigma ty'
             in
             (sigma, e::subst,e::evarl,n+1)
         | LocalDef (na,b,ty) ->
diff --git a/test-suite/bugs/closed/bug_13216.v b/test-suite/bugs/closed/bug_13216.v
new file mode 100644
index 0000000000..54a28a9c53
--- /dev/null
+++ b/test-suite/bugs/closed/bug_13216.v
@@ -0,0 +1,4 @@
+Class A.
+Declare Instance a:A.
+Inductive T `(A) := C.
+Definition f x := match x with C _ => 0 end.
-- 
cgit v1.2.3


From 1a36a0e4b29b358b05b02515c6c001672e3491e8 Mon Sep 17 00:00:00 2001
From: Hugo Herbelin
Date: Mon, 19 Oct 2020 08:18:29 +0200
Subject: Adding change log for #13217.

---
 .../13217-master+fix13216-typeclass-for-match-return-clause.rst      | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 doc/changelog/02-specification-language/13217-master+fix13216-typeclass-for-match-return-clause.rst

diff --git a/doc/changelog/02-specification-language/13217-master+fix13216-typeclass-for-match-return-clause.rst b/doc/changelog/02-specification-language/13217-master+fix13216-typeclass-for-match-return-clause.rst
new file mode 100644
index 0000000000..2d8230b965
--- /dev/null
+++ b/doc/changelog/02-specification-language/13217-master+fix13216-typeclass-for-match-return-clause.rst
@@ -0,0 +1,5 @@
+- **Fixed:**
+  Allow use of type classes inference for the return predicate of a :n:`match`
+  (was deactivated in versions 8.10 to 8.12, `#13217 <https://github.com/coq/coq/pull/13217>`_,
+  fixes `#13216 <https://github.com/coq/coq/issues/13216>`_,
+  by Hugo Herbelin).
-- 
cgit v1.2.3