diff --git a/backend/src/cmakegen.cpp b/backend/src/cmakegen.cpp
index 00deeb95..8ab07ee9 100644
--- a/backend/src/cmakegen.cpp
+++ b/backend/src/cmakegen.cpp
@@ -32,9 +32,6 @@ endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
 endif()
-if(NOT Chplx_DIR)
-  message(FATAL_ERROR "Chplx_DIR variable undefined")
-endif()
 set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 find_package(fmt REQUIRED CONFIG)
 find_package(HPX REQUIRED CONFIG)
diff --git a/backend/test/arr/CMakeLists.txt.good b/backend/test/arr/CMakeLists.txt.good
index 74648692..4b68fdf0 100644
--- a/backend/test/arr/CMakeLists.txt.good
+++ b/backend/test/arr/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(arr)
 add_executable(arr arr.cpp arr_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/cfg/CMakeLists.txt.good b/backend/test/cfg/CMakeLists.txt.good
index 8ae3fa57..a33fce76 100644
--- a/backend/test/cfg/CMakeLists.txt.good
+++ b/backend/test/cfg/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(cfg)
 add_executable(cfg cfg.cpp cfg_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/cond/CMakeLists.txt.good b/backend/test/cond/CMakeLists.txt.good
index c43335ea..3a902957 100644
--- a/backend/test/cond/CMakeLists.txt.good
+++ b/backend/test/cond/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(cond)
 add_executable(cond cond.cpp cond_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/expr/CMakeLists.txt.good b/backend/test/expr/CMakeLists.txt.good
index f62bbec5..fe25f86a 100644
--- a/backend/test/expr/CMakeLists.txt.good
+++ b/backend/test/expr/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(expr)
 add_executable(expr expr.cpp expr_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/fn/CMakeLists.txt.good b/backend/test/fn/CMakeLists.txt.good
index 647ad263..777edc71 100644
--- a/backend/test/fn/CMakeLists.txt.good
+++ b/backend/test/fn/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(fn)
 add_executable(fn fn.cpp fn_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/fnc/CMakeLists.txt.good b/backend/test/fnc/CMakeLists.txt.good
index 02978b14..c1555840 100644
--- a/backend/test/fnc/CMakeLists.txt.good
+++ b/backend/test/fnc/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(fnc)
 add_executable(fnc fnc.cpp fnc_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/forall/CMakeLists.txt.good b/backend/test/forall/CMakeLists.txt.good
index c63d81ee..27bd19bc 100644
--- a/backend/test/forall/CMakeLists.txt.good
+++ b/backend/test/forall/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(forall)
 add_executable(forall forall.cpp forall_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/heat/CMakeLists.txt.good b/backend/test/heat/CMakeLists.txt.good
index cabbb900..1eb61bbf 100644
--- a/backend/test/heat/CMakeLists.txt.good
+++ b/backend/test/heat/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(heat)
 add_executable(heat heat.cpp heat_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")
diff --git a/backend/test/heat/heat.hpp.good b/backend/test/heat/heat.hpp.good
index 8932d537..a1fc57a6 100644
--- a/backend/test/heat/heat.hpp.good
+++ b/backend/test/heat/heat.hpp.good
@@ -13,24 +13,24 @@
 namespace heat {
     extern struct __thisModule* __this;
 
-#line 19 "heat.chpl"
+#line 17 "heat.chpl"
     extern std::int64_t ghosts;
-#line 20 "heat.chpl"
+#line 18 "heat.chpl"
     extern double k;
-#line 21 "heat.chpl"
+#line 19 "heat.chpl"
     extern double dt;
-#line 22 "heat.chpl"
+#line 20 "heat.chpl"
     extern double dx;
-#line 24 "heat.chpl"
+#line 22 "heat.chpl"
     extern std::int64_t nx;
-#line 25 "heat.chpl"
+#line 23 "heat.chpl"
     extern std::int64_t nt;
-#line 26 "heat.chpl"
+#line 24 "heat.chpl"
     extern std::int64_t threads;
 
     struct __thisModule
     {
-#line 33 "heat.chpl"
+#line 26 "heat.chpl"
         void update(chplx::Array<double, chplx::Domain<1>>& d,
             chplx::Array<double, chplx::Domain<1>>& d2);
 
diff --git a/backend/test/tup/CMakeLists.txt.good b/backend/test/tup/CMakeLists.txt.good
index a932e56a..bff223df 100644
--- a/backend/test/tup/CMakeLists.txt.good
+++ b/backend/test/tup/CMakeLists.txt.good
@@ -8,11 +8,11 @@ if(NOT CMAKE_BUILD_TYPE)
 endif()
 project(tup)
 add_executable(tup tup.cpp tup_driver.cpp)
-if(NOT APPLE)
-  set(CMAKE_CXX_STANDARD 20)
-endif()
+set(CMAKE_CXX_STANDARD 20)
+set(CXX_EXTENSIONS OFF)
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
 if(NOT WIN32 AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang" AND NOT APPLE)
-  set(CMAKE_CXX_FLAGS ${CMAKE_CXX_FLAGS} -stdlib=libc++)
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++20 -stdlib=libc++")
 endif()
 if(NOT Chplx_DIR)
   message(FATAL_ERROR "Chplx_DIR variable undefined")