diff --git a/src/library/CMakeLists.txt b/src/library/CMakeLists.txt
index b1907ad148..bf27a112d7 100644
--- a/src/library/CMakeLists.txt
+++ b/src/library/CMakeLists.txt
@@ -10,4 +10,4 @@ add_library(library OBJECT expr_lt.cpp io_state.cpp
   locals.cpp messages.cpp message_builder.cpp check.cpp
   profiling.cpp time_task.cpp
   scope_pos_info_provider.cpp formatter.cpp json.cpp
-  pos_info_provider.cpp abstract_type_context.cpp aux_match.cpp)
+  pos_info_provider.cpp abstract_type_context.cpp)
diff --git a/src/library/aux_match.cpp b/src/library/aux_match.cpp
deleted file mode 100644
index 11fc010d0c..0000000000
--- a/src/library/aux_match.cpp
+++ /dev/null
@@ -1,71 +0,0 @@
-/*
-Copyright (c) 2018 Microsoft Corporation. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-
-Author: Leonardo de Moura
-*/
-#include <algorithm>
-#include "kernel/environment.h"
-#include "kernel/instantiate.h"
-#include "library/replace_visitor.h"
-
-namespace lean {
-static name * g_aux_match_suffix = nullptr;
-
-name const & get_aux_match_suffix() {
-    return *g_aux_match_suffix;
-}
-
-name mk_aux_match_suffix(unsigned idx) {
-    return g_aux_match_suffix->append_after(idx);
-}
-
-bool is_aux_match(name const & n) {
-    return
-        is_internal_name(n) && !n.is_atomic() && n.is_string() &&
-        strncmp(n.get_string().data(), "_match", 6) == 0;
-}
-
-struct unfold_aux_match_fn : public replace_visitor {
-    environment const & m_env;
-    unfold_aux_match_fn(environment const & env):m_env(env) {}
-
-    virtual expr visit_app(expr const & e) override {
-        buffer<expr> args;
-        expr const & fn = get_app_args(e, args);
-        expr new_fn   = visit(fn);
-        bool modified = !is_eqp(fn, new_fn);
-        for (expr & arg : args) {
-            expr new_arg = visit(arg);
-            if (!is_eqp(new_arg, arg))
-                modified = true;
-            arg = new_arg;
-        }
-        if (is_constant(new_fn)) {
-            name const & n = const_name(new_fn);
-            if (is_aux_match(n)) {
-                new_fn = instantiate_value_lparams(m_env.get(n), const_levels(new_fn));
-                std::reverse(args.begin(), args.end());
-                return visit(apply_beta(new_fn, args.size(), args.data()));
-            }
-        }
-        if (!modified)
-            return e;
-        else
-            return mk_app(new_fn, args);
-    }
-};
-
-expr unfold_aux_match(environment const & env, expr const & e) {
-    return unfold_aux_match_fn(env)(e);
-}
-
-void initialize_aux_match() {
-    g_aux_match_suffix = new name("_match");
-    mark_persistent(g_aux_match_suffix->raw());
-}
-
-void finalize_aux_match() {
-    delete g_aux_match_suffix;
-}
-}
diff --git a/src/library/aux_match.h b/src/library/aux_match.h
deleted file mode 100644
index afe3349beb..0000000000
--- a/src/library/aux_match.h
+++ /dev/null
@@ -1,16 +0,0 @@
-/*
-Copyright (c) 2018 Microsoft Corporation. All rights reserved.
-Released under Apache 2.0 license as described in the file LICENSE.
-
-Author: Leonardo de Moura
-*/
-#pragma once
-#include "kernel/environment.h"
-namespace lean {
-name const & get_aux_match_suffix();
-name mk_aux_match_suffix(unsigned idx);
-expr unfold_aux_match(environment const & env, expr const & e);
-bool is_aux_match(name const & n);
-void initialize_aux_match();
-void finalize_aux_match();
-}
diff --git a/src/library/compiler/lcnf.cpp b/src/library/compiler/lcnf.cpp
index 8f390c51ec..ed1d8305d7 100644
--- a/src/library/compiler/lcnf.cpp
+++ b/src/library/compiler/lcnf.cpp
@@ -17,7 +17,6 @@ Author: Leonardo de Moura
 #include "library/aux_recursors.h"
 #include "library/constants.h"
 #include "library/projection.h"
-#include "library/aux_match.h"
 #include "library/compiler/util.h"
 #include "library/compiler/implemented_by_attribute.h"
 
@@ -622,8 +621,7 @@ public:
 };
 
 expr to_lcnf_core(environment const & env, local_ctx const & lctx, expr const & e) {
-    expr new_e = unfold_aux_match(env, e);
-    new_e      = unfold_macro_defs(env, new_e);
+    expr new_e = unfold_macro_defs(env, e);
     return to_lcnf_fn(env, lctx)(new_e);
 }
 
diff --git a/src/library/init_module.cpp b/src/library/init_module.cpp
index 78a2548334..304ca15850 100644
--- a/src/library/init_module.cpp
+++ b/src/library/init_module.cpp
@@ -24,7 +24,6 @@ Author: Leonardo de Moura
 #include "library/time_task.h"
 #include "library/formatter.h"
 #include "library/pos_info_provider.h"
-#include "library/aux_match.h"
 
 namespace lean {
 void initialize_library_core_module() {
@@ -44,7 +43,6 @@ void finalize_library_core_module() {
 }
 
 void initialize_library_module() {
-    initialize_aux_match();
     initialize_local_context();
     initialize_metavar_context();
     initialize_print();
@@ -76,6 +74,5 @@ void finalize_library_module() {
     finalize_print();
     finalize_metavar_context();
     finalize_local_context();
-    finalize_aux_match();
 }
 }
diff --git a/src/library/type_context.cpp b/src/library/type_context.cpp
index 75ba55c34f..3ec1d22620 100644
--- a/src/library/type_context.cpp
+++ b/src/library/type_context.cpp
@@ -29,7 +29,6 @@ Author: Leonardo de Moura
 #include "library/aux_recursors.h"
 #include "library/num.h"
 #include "library/check.h"
-#include "library/aux_match.h"
 #include "library/time_task.h"
 
 namespace lean {
diff --git a/src/library/util.cpp b/src/library/util.cpp
index 17979f2fd4..94c4cbffff 100644
--- a/src/library/util.cpp
+++ b/src/library/util.cpp
@@ -22,7 +22,6 @@ Author: Leonardo de Moura
 #include "library/projection.h"
 #include "library/replace_visitor.h"
 #include "library/type_context.h"
-// #include "library/string.h"
 #include "library/num.h"
 #include "version.h"
 #include "githash.h" // NOLINT