diff --git a/build_defs/cpp_opts.bzl b/build_defs/cpp_opts.bzl
index d8646d1681fe6..f46b7dcc0a65c 100644
--- a/build_defs/cpp_opts.bzl
+++ b/build_defs/cpp_opts.bzl
@@ -17,10 +17,7 @@ COPTS = select({
         "/wd4996",  # The compiler encountered a deprecated declaration.
     ],
     "//conditions:default": [
-        "-DHAVE_ZLIB",
-        "-Woverloaded-virtual",
         "-Wno-sign-compare",
-        "-Wno-nonnull",
     ],
 })
 
diff --git a/ci/Linux.bazelrc b/ci/Linux.bazelrc
index b4ec98f8c7965..3cdf40d218441 100644
--- a/ci/Linux.bazelrc
+++ b/ci/Linux.bazelrc
@@ -1,4 +1,5 @@
 import common.bazelrc
 
 build --cxxopt=-std=c++14 --host_cxxopt=-std=c++14
+build --cxxopt="-Woverloaded-virtual"
 build --copt="-Werror" --copt="-Wno-sign-compare" --copt="-Wno-sign-conversion" --copt="-Wno-error=sign-conversion" --copt="-Wno-deprecated-declarations"
diff --git a/ci/macOS.bazelrc b/ci/macOS.bazelrc
index e426b59f5799b..e91f62639a2d6 100644
--- a/ci/macOS.bazelrc
+++ b/ci/macOS.bazelrc
@@ -1,6 +1,7 @@
 import common.bazelrc
 
 build --cxxopt=-std=c++14 --host_cxxopt=-std=c++14
+build --cxxopt="-Woverloaded-virtual"
 build --copt="-Werror" --copt="-Wno-sign-compare" --copt="-Wno-sign-conversion" --copt="-Wno-error=sign-conversion" --copt="-Wno-deprecated-declarations"
 common --repo_env=BAZEL_NO_APPLE_CPP_TOOLCHAIN=1
-common --xcode_version_config=@com_google_protobuf//.github:host_xcodes
\ No newline at end of file
+common --xcode_version_config=@com_google_protobuf//.github:host_xcodes
diff --git a/src/google/protobuf/io/BUILD.bazel b/src/google/protobuf/io/BUILD.bazel
index 27c444480168d..eb865df5669c5 100644
--- a/src/google/protobuf/io/BUILD.bazel
+++ b/src/google/protobuf/io/BUILD.bazel
@@ -150,7 +150,10 @@ cc_library(
     name = "gzip_stream",
     srcs = ["gzip_stream.cc"],
     hdrs = ["gzip_stream.h"],
-    copts = COPTS,
+    copts = COPTS + select({
+        "//build_defs:config_msvc": [],
+        "//conditions:default": ["-DHAVE_ZLIB"],
+    }),
     strip_include_prefix = "/src",
     deps = [
         ":io",
@@ -192,7 +195,10 @@ cc_test(
         "tokenizer_unittest.cc",
         "zero_copy_stream_unittest.cc",
     ],
-    copts = COPTS,
+    copts = COPTS + select({
+        "//build_defs:config_msvc": [],
+        "//conditions:default": ["-DHAVE_ZLIB"],
+    }),
     deps = [
         ":gzip_stream",
         ":io",