refactor(library/init/meta): move defeq simplifier related tactics to separate file

library/init/meta/default.lean

@@ -11,4 +11,4 @@ import init.meta.injection_tactic init.meta.relation_tactics init.meta.fun_info
 import init.meta.congr_lemma init.meta.match_tactic init.meta.ac_tactics
 import init.meta.backward init.meta.rewrite_tactic init.meta.unfold_tactic
 import init.meta.mk_dec_eq_instance init.meta.mk_inhabited_instance
-import init.meta.simp_tactic
+import init.meta.simp_tactic init.meta.defeq_simp_tactic

library/init/meta/defeq_simp_tactic.lean

@@ -0,0 +1,27 @@
+/-
+Copyright (c) 2016 Microsoft Corporation. All rights reserved.
+Released under Apache 2.0 license as described in the file LICENSE.
+Authors: Leonardo de Moura
+-/
+prelude
+import init.meta.tactic
+
+namespace tactic
+/- Simplify the given expression using [defeq] lemmas.
+   The resulting expression is definitionally equal to the input. -/
+meta_constant defeq_simp_core : transparency → expr → tactic expr
+
+meta_definition defeq_simp : expr → tactic expr :=
+defeq_simp_core reducible
+
+meta_definition dsimp : tactic unit :=
+target >>= defeq_simp >>= change
+
+meta_definition dsimp_at (H : expr) : tactic unit :=
+do num_reverted : ℕ ← revert H,
+   (expr.pi n bi d b : expr) ← target | failed,
+   H_simp : expr ← defeq_simp d,
+   change $ expr.pi n bi H_simp b,
+   intron num_reverted
+
+end tactic

library/init/meta/tactic.lean

@@ -163,9 +163,6 @@ meta_constant to_expr       : qexpr → tactic expr
 meta_constant is_class      : expr → tactic bool
 /- Try to create an instance of the given type class. -/
 meta_constant mk_instance   : expr → tactic expr
-/- Simplify the given expression using [defeq] lemmas.
-   The resulting expression is definitionally equal to the input. -/
-meta_constant defeq_simp_core : transparency → expr → tactic expr
 /- Change the target of the main goal.
    The input expression must be definitionally equal to the current target. -/
 meta_constant change        : expr → tactic unit
@@ -316,22 +313,6 @@ do gs ← get_goals,
    | _              := skip
    end
 
--- TODO(Leo): remove unifier.conservative after we finish new elaborator
-set_option unifier.conservative true
-
-meta_definition defeq_simp : expr → tactic expr :=
-defeq_simp_core reducible
-
-meta_definition dsimp : tactic unit :=
-target >>= defeq_simp >>= change
-
-meta_definition dsimp_at (H : expr) : tactic unit :=
-do num_reverted : ℕ ← revert H,
-   (expr.pi n bi d b : expr) ← target | failed,
-   H_simp : expr ← defeq_simp d,
-   change $ expr.pi n bi H_simp b,
-   intron num_reverted
-
 /- Return the number of goals that need to be solved -/
 meta_definition num_goals     : tactic nat :=
 do gs ← get_goals,