diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6bb834e3..2a20282f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -46,6 +46,44 @@ jobs:
       - name: Test
         run: ctest --test-dir build --output-on-failure
 
+  linux-sanitizers:
+    name: Linux GCC ASAN+UBSAN ${{ matrix.build_type }}
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        build_type: [Debug, Release]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Configure
+        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
+
+      - name: Build
+        run: cmake --build build -j
+
+      - name: Test
+        run: ctest --test-dir build --output-on-failure
+
+  macos-sanitizers:
+    name: macOS AppleClang ASAN+UBSAN ${{ matrix.build_type }}
+    runs-on: macos-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        build_type: [Debug, Release]
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Configure
+        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.build_type }} -DENABLE_ADDRESS_SANITIZER=ON -DENABLE_UNDEFINED_SANITIZER=ON
+
+      - name: Build
+        run: cmake --build build -j
+
+      - name: Test
+        run: ctest --test-dir build --output-on-failure
+
   windows:
     name: Windows MSVC ${{ matrix.build_type }}
     runs-on: windows-latest
diff --git a/appveyor.yml b/appveyor.yml
deleted file mode 100644
index 5a4fe67e..00000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,23 +0,0 @@
-version: 6.1.x.{build}
-image:
-  - Visual Studio 2019
-environment:
-  matrix:
-  - VS_VERSION: "Visual Studio 16"
-build_script:
-- cmd: >-
-    mkdir build
-
-    cd build
-
-    cmake c:\Projects\chaiscript -G "%VS_VERSION%" -DBUILD_TESTING:BOOL=ON -DBUILD_MODULES:BOOL=ON
-
-    cmake --build . --config Debug
-test_script:
-- cmd: ctest -C Debug
-notifications:
-- provider: Webhook
-  url: https://webhooks.gitter.im/e/9ff725a985b5679d1d5d
-  on_build_success: true
-  on_build_failure: true
-  on_build_status_changed: false
diff --git a/src/main.cpp b/src/main.cpp
index 6ec746fb..ab94b5d1 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,6 +7,7 @@
 // This is an open source non-commercial project. Dear PVS-Studio, please check it.
 // PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
 
+#include <chrono>
 #include <iostream>
 #include <list>
 #include <regex>
diff --git a/unittests/now_function.chai b/unittests/now_function.chai
new file mode 100644
index 00000000..5825cdec
--- /dev/null
+++ b/unittests/now_function.chai
@@ -0,0 +1,3 @@
+// Regression test for issue #660: now() requires <chrono> include
+var t = now()
+assert_true(t > 0)