diff --git a/infer/.merlin b/infer/.merlin
index 0f35950a2..f43f07902 100644
--- a/infer/.merlin
+++ b/infer/.merlin
@@ -1,7 +1,7 @@
 S src/**
 B _build/infer/**
 PKG atdgen
-PKG core_extended
+PKG core
 PKG extlib
 PKG javalib
 PKG ounit
diff --git a/infer/src/Makefile b/infer/src/Makefile
index c89dfb9af..e8fa6358b 100644
--- a/infer/src/Makefile
+++ b/infer/src/Makefile
@@ -284,7 +284,7 @@ toplevel: init $(STACKTREE_ATDGEN_STUBS) $(INFERPRINT_ATDGEN_STUBS) $(CLANG_ATDG
 checkCopyright: $(CHECKCOPYRIGHT_BIN)
 
 $(CHECKCOPYRIGHT_BIN): sanitize $(BUILD_DIR) $(CHECKCOPYRIGHT_MAIN).ml
-	rebuild -quiet -r -j $(NCPU) -build-dir $(INFER_BUILD_DIR) -pkgs core_extended,str -tag thread -use-ocamlfind $(CHECKCOPYRIGHT_MAIN).native
+	rebuild -quiet -r -j $(NCPU) -build-dir $(INFER_BUILD_DIR) -pkgs core,str -tag thread -use-ocamlfind $(CHECKCOPYRIGHT_MAIN).native
 	$(INSTALL_PROGRAM) $(INFER_BUILD_DIR)/$(CHECKCOPYRIGHT_MAIN).native $(CHECKCOPYRIGHT_BIN)
 
 define gen_atdgen_rules
diff --git a/infer/src/scripts/checkCopyright.ml b/infer/src/scripts/checkCopyright.ml
index 3048bd9b1..17e2b4288 100644
--- a/infer/src/scripts/checkCopyright.ml
+++ b/infer/src/scripts/checkCopyright.ml
@@ -7,7 +7,7 @@
  * of patent rights can be found in the PATENTS file in the same directory.
  *)
 
-open! Core_extended.Std
+open! Core.Std
 
 module F = Format
 
@@ -178,7 +178,7 @@ let update_file fname mono fb_year com_style prefix cstart cend lines_arr =
       F.fprintf fmt "%s@\n" lines_arr.(i)
     done;
     F.fprintf fmt "@?";
-    close_out cout
+    Out_channel.close cout
   with _ -> ()
 
 let com_style_of_lang = [
@@ -222,11 +222,7 @@ let output_diff fname lines_arr cstart n cend len mono fb_year com_style prefix
     update_file fname mono fb_year com_style prefix cstart cend lines_arr
 
 let check_copyright fname =
-  let lines =
-    let readline =
-      let linebuf = Linebuf.create fname in
-      fun () -> Linebuf.try_read linebuf in
-    Lazy_list.to_list (Lazy_list.uniter ~f:readline) in
+  let lines = In_channel.with_file fname ~f:In_channel.input_lines in
   match find_copyright_line lines 0 with
   | None ->
       if file_should_have_copyright fname then
diff --git a/opam b/opam
index 6c71b22f5..a7a0895b2 100644
--- a/opam
+++ b/opam
@@ -27,7 +27,7 @@ remove: [
 ocaml-version: [ >= "4.02.1" ]
 depends: [
   "atdgen" {>="1.6.0"}
-  "core_extended" {>="113.33.03"}
+  "core" {>="113.33.03"}
   "conf-autoconf"
   "extlib-compat" {>="1.5.4"}
   "javalib" {>="2.3.3"}
diff --git a/package.json b/package.json
index d8373c237..be5b4cbf9 100644
--- a/package.json
+++ b/package.json
@@ -12,7 +12,7 @@
   "name": "infer",
   "dependencies": {
     "@opam-alpha/ocamlfind": "*",
-    "@opam-alpha/core_extended": "113.33.3",
+    "@opam-alpha/core": "113.33.3",
     "@opam-alpha/ocaml": "4.2.3",
     "@opam-alpha/sawja": "^ 1.5.2",
     "@opam-alpha/atdgen": "^ 1.10.0",
diff --git a/yarn.lock b/yarn.lock
index 302878b22..7bf6a1e48 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -90,11 +90,11 @@
   dependencies:
     conf-which-actual "git://github.com/npm-opam/conf-which.git#1.0.0"
 
-"@opam-alpha/core_extended@113.33.3":
+"@opam-alpha/core@113.33.3":
   version "113.33.3"
-  resolved core_extended-113.33.3.tgz#119bb3614537bc9fe557b3470b2a4398f721af79
+  resolved core-113.33.3.tgz#f7a586a0f9a3efbe195c1b98ebd51ccaf2f8bfd9
   dependencies:
-    core_extended-actual "git://github.com/npm-opam/core_extended.git#113.33.03"
+    core-actual "git://github.com/npm-opam/core.git#113.33.03"
 
 "@opam-alpha/core_kernel@>= 113.33.03 < 113.34.00":
   version "113.33.3"
@@ -102,12 +102,6 @@
   dependencies:
     core_kernel-actual "git://github.com/npm-opam/core_kernel.git#113.33.03"
 
-"@opam-alpha/core@>= 113.33.03 < 113.34.00":
-  version "113.33.3"
-  resolved core-113.33.3.tgz#f7a586a0f9a3efbe195c1b98ebd51ccaf2f8bfd9
-  dependencies:
-    core-actual "git://github.com/npm-opam/core.git#113.33.03"
-
 "@opam-alpha/cppo@*", "@opam-alpha/cppo@>= 1.1.2", "@opam-alpha/cppo@>= 1.2.2":
   version "1.4.0"
   resolved cppo-1.4.0.tgz#e9572a069d93fd9140122036dc7371d6581093f6
@@ -132,7 +126,7 @@
   dependencies:
     fieldslib-actual "git://github.com/npm-opam/fieldslib.git#113.33.03"
 
-"@opam-alpha/javalib@^ 2.3.3", "@opam-alpha/javalib@>= 2.3.2":
+"@opam-alpha/javalib@>= 2.3.2", "@opam-alpha/javalib@^ 2.3.3":
   version "2.3.3"
   resolved javalib-2.3.3.tgz#1cb16fe3bbc6998a13d3ae6725c1189989555a18
   dependencies:
@@ -174,7 +168,7 @@
   dependencies:
     merlin-actual "git://github.com/npm-opam/merlin.git#2.5.1"
 
-"@opam-alpha/ocaml@= 4.02.3", "@opam-alpha/ocaml@4.2.3":
+"@opam-alpha/ocaml@4.2.3", "@opam-alpha/ocaml@= 4.02.3":
   version "4.2.3"
   resolved ocaml-4.2.3.tgz#44c6e23fbb716196d4a6121f7751e09c0ad34018
   dependencies:
@@ -358,18 +352,12 @@
   dependencies:
     ppx_variants_conv-actual "git://github.com/npm-opam/ppx_variants_conv.git#113.33.03"
 
-"@opam-alpha/re@*", "@opam-alpha/re@^ 1.5.0", "@opam-alpha/re@>= 1.5.0":
+"@opam-alpha/re@*", "@opam-alpha/re@>= 1.5.0", "@opam-alpha/re@^ 1.5.0":
   version "1.6.1"
   resolved re-1.6.1.tgz#e196b2566b10afb76011c71c44d7b0fbf5a70e6f
   dependencies:
     re-actual "git://github.com/npm-opam/re.git#1.6.1"
 
-"@opam-alpha/re2@>= 113.33.03 < 113.34.00":
-  version "113.33.3"
-  resolved re2-113.33.3.tgz#7244dbd26c2ffd454734e85494372584801a63f8
-  dependencies:
-    re2-actual "git://github.com/npm-opam/re2.git#113.33.03"
-
 "@opam-alpha/react@*", "@opam-alpha/react@>= 1.0.0":
   version "1.2.0"
   resolved react-1.2.0.tgz#ff94aef21609ce9cc24d45b2a2e0fae97f5234a1
@@ -394,12 +382,6 @@
   dependencies:
     sexplib-actual "git://github.com/npm-opam/sexplib.git#113.33.03"
 
-"@opam-alpha/textutils@>= 113.33.03 < 113.34.00":
-  version "113.33.3"
-  resolved textutils-113.33.3.tgz#76e395f71810015e894a8e24599bdf5e16f29422
-  dependencies:
-    textutils-actual "git://github.com/npm-opam/textutils.git#113.33.03"
-
 "@opam-alpha/typerep@>= 113.33.03 < 113.34.00":
   version "113.33.3"
   resolved typerep-113.33.3.tgz#4754e4cdc3ab33f67b4fd2511476d61c8582b778
@@ -595,12 +577,12 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"core_extended-actual@git://github.com/npm-opam/core_extended.git#113.33.03":
+"core-actual@git://github.com/npm-opam/core.git#113.33.03":
   version "113.33.3"
-  resolved core_extended.git-547ba52651d1315f9c49e8292c3be0edd2614fee#ded3bb6c418a0b5733b5bb45b2737d6cf23e9160
+  resolved core.git-c3882164058f3222be59d1bbabe455ec37060713#4a82970a8e31aa5fe29e22f84291d6c431e02d36
   dependencies:
     "@opam-alpha/bin_prot" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/core" ">= 113.33.03 < 113.34.00"
+    "@opam-alpha/core_kernel" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/fieldslib" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/js-build-tools" ">= 113.33.04 < 113.34.00"
     "@opam-alpha/ocamlbuild" "*"
@@ -611,9 +593,7 @@
     "@opam-alpha/ppx_expect" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/ppx_inline_test" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/ppx_jane" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/re2" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/sexplib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/textutils" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/typerep" ">= 113.33.03 < 113.34.00"
     "@opam-alpha/variantslib" ">= 113.33.03 < 113.34.00"
     dependency-env "https://github.com/npm-ml/dependency-env.git"
@@ -645,30 +625,6 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"core-actual@git://github.com/npm-opam/core.git#113.33.03":
-  version "113.33.3"
-  resolved core.git-c3882164058f3222be59d1bbabe455ec37060713#4a82970a8e31aa5fe29e22f84291d6c431e02d36
-  dependencies:
-    "@opam-alpha/bin_prot" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/core_kernel" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/fieldslib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/js-build-tools" ">= 113.33.04 < 113.34.00"
-    "@opam-alpha/ocamlbuild" "*"
-    "@opam-alpha/ocamlfind" ">= 1.3.2"
-    "@opam-alpha/ppx_assert" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_bench" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_driver" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_expect" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_inline_test" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_jane" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/sexplib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/typerep" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/variantslib" ">= 113.33.03 < 113.34.00"
-    dependency-env "https://github.com/npm-ml/dependency-env.git"
-    nopam "https://github.com/yunxing/nopam.git"
-    opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
-    substs "https://github.com/yunxing/substs.git"
-
 "cppo-actual@git://github.com/npm-opam/cppo.git#1.4.0":
   version "1.4.0"
   resolved cppo.git-bae7485b77d4716ae4a9c3707fb74d471aa0eaa7#ce22772fc95f9bf01a221ff84500dbeaa4e48b30
@@ -680,15 +636,9 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"dependency-env@https://github.com/npm-ml/dependency-env.git", "dependency-env@https://github.com/reasonml/dependency-env.git":
-  version "0.0.0"
-  resolved dependency-env.git-b6710d7ccc0ea940ce55c4149675dd4ad6a9b94b#1dfad199e8cd9fba48513f85c1383874c7e83e5e
-  dependencies:
-    resolve "^1.1.7"
-
-"dependencyEnv@https://github.com/reasonml/dependency-env":
+"dependency-env@git+https://github.com/reasonml/dependency-env.git", "dependency-env@https://github.com/npm-ml/dependency-env.git", "dependencyEnv@git+https://github.com/reasonml/dependency-env.git":
   version "0.0.0"
-  resolved dependency-env-b6710d7ccc0ea940ce55c4149675dd4ad6a9b94b#1dfad199e8cd9fba48513f85c1383874c7e83e5e
+  resolved dependency-env.git-20ccabcf9f4854fdcda3f965ce410487515d7dc7#fb1a38d19682e7f754e6154d276ce6fdfbade9f7
   dependencies:
     resolve "^1.1.7"
 
@@ -813,7 +763,7 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"nopam@https://github.com/reasonml/nopam.git", "nopam@https://github.com/yunxing/nopam.git":
+"nopam@git+https://github.com/reasonml/nopam.git", "nopam@https://github.com/yunxing/nopam.git":
   version "0.0.1"
   resolved nopam.git-8584695c8e2615857d4f58a0dec7bae3a9059a54#49cd1b4ccc32d588cdd3a671d4cc6d773803396b
 
@@ -851,7 +801,7 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"opam-installer-bin@https://github.com/yunxing/opam-installer-bin.git":
+"opam-installer-bin@git+https://github.com/yunxing/opam-installer-bin.git", "opam-installer-bin@https://github.com/yunxing/opam-installer-bin.git":
   version "0.0.0"
   resolved opam-installer-bin.git-689ede681217f76fb2f82a9f4528e192a5b543ba#b7704eda021a9fe18a9a37454868e1bbf102e0a0
   dependencies:
@@ -1292,30 +1242,6 @@
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"re2-actual@git://github.com/npm-opam/re2.git#113.33.03":
-  version "113.33.3"
-  resolved re2.git-78dc04b248c786958738e19f2a3e6b8f586dfa1a#74dae72ed9798a85940f8a0685f55664d1a25067
-  dependencies:
-    "@opam-alpha/bin_prot" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/core_kernel" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/fieldslib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/js-build-tools" ">= 113.33.04 < 113.34.00"
-    "@opam-alpha/ocamlbuild" "*"
-    "@opam-alpha/ocamlfind" ">= 1.3.2"
-    "@opam-alpha/ppx_assert" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_bench" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_driver" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_expect" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_inline_test" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_jane" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/sexplib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/typerep" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/variantslib" ">= 113.33.03 < 113.34.00"
-    dependency-env "https://github.com/npm-ml/dependency-env.git"
-    nopam "https://github.com/yunxing/nopam.git"
-    opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
-    substs "https://github.com/yunxing/substs.git"
-
 "react-actual@git://github.com/npm-opam/react.git#1.2.0":
   version "1.2.0"
   resolved react.git-4870dc6320c332cd2e0b47ec6241ce1ad6099bca#47ef2c99683defe94d4144165f0e631c56fdc67f
@@ -1389,35 +1315,11 @@ resolve@^1.1.7:
     opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
     substs "https://github.com/yunxing/substs.git"
 
-"substs@https://github.com/yunxing/substs.git":
+"substs@git+https://github.com/yunxing/substs.git", "substs@https://github.com/yunxing/substs.git":
   version "0.0.1"
   resolved substs.git-fd480dcdb4aed3fa9128fd819a546e3a7770040f#3a935dc6de26a5dfae899eca93a510bae55e57a4
 
-"textutils-actual@git://github.com/npm-opam/textutils.git#113.33.03":
-  version "113.33.3"
-  resolved textutils.git-07a6c24a179f857719f98659c35760f1d57ac824#1ba178630f5c3a2a5bd07b74c27469f93f53e863
-  dependencies:
-    "@opam-alpha/bin_prot" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/core" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/fieldslib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/js-build-tools" ">= 113.33.04 < 113.34.00"
-    "@opam-alpha/ocamlbuild" "*"
-    "@opam-alpha/ocamlfind" ">= 1.3.2"
-    "@opam-alpha/ppx_assert" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_bench" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_driver" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_expect" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_inline_test" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/ppx_jane" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/sexplib" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/typerep" ">= 113.33.03 < 113.34.00"
-    "@opam-alpha/variantslib" ">= 113.33.03 < 113.34.00"
-    dependency-env "https://github.com/npm-ml/dependency-env.git"
-    nopam "https://github.com/yunxing/nopam.git"
-    opam-installer-bin "https://github.com/yunxing/opam-installer-bin.git"
-    substs "https://github.com/yunxing/substs.git"
-
-tuareg@yunxing/tuareg:
+"tuareg@github:yunxing/tuareg":
   version "1.0.0"
   resolved a90c0a2f202529a641d369c3b18b0c785a4a7e99#aa3a72a7726b1dd4fd1c809f893cc7ed6d2d420d