diff --git a/meson.build b/meson.build
index 4038188..0170d69 100644
--- a/meson.build
+++ b/meson.build
@@ -45,8 +45,24 @@ add_project_arguments(
 add_project_arguments(
     cc.get_supported_arguments(
         '-D_POSIX_C_SOURCE=200112L',
+        '-Wconversion',
         '-Wdeclaration-after-statement',
-        '-Wconversion'
+        '-Wdouble-promotion',
+        '-Wduplicated-branches',
+        '-Wduplicated-cond',
+        '-Wendif-labels',
+        '-Wformat=2',
+        '-Wformat-overflow=2',
+        '-Wformat-signedness',
+        '-Wformat-truncation=1',
+        '-Winit-self',
+        '-Wlogical-op',
+        '-Wmissing-prototypes',
+        '-Wnull-dereference',
+        '-Wno-return-local-addr',
+        '-Wshadow',
+        '-Wuninitialized',
+        '-Wvla',
     ),
     language: 'c'
 )
diff --git a/tests/merr-test.c b/tests/merr-test.c
index 2b48fb3..0118a6f 100644
--- a/tests/merr-test.c
+++ b/tests/merr-test.c
@@ -64,7 +64,7 @@ test_merr_long_path(void)
     g_assert_cmpint(err, !=, 0);
 
     expected_sz = (size_t)snprintf(
-        expected, sizeof(expected), "%*s:%d: %s (%d)", MERR_MAX_PATH_LENGTH, merr_file(err),
+        expected, sizeof(expected), "%*s:%d: %s (%d)", (int)MERR_MAX_PATH_LENGTH, merr_file(err),
         merr_lineno(err), strerror(merr_errno(err)), merr_errno(err));
     found_sz = merr_strerrorx(err, found, sizeof(found), ctx_stringify);
     g_assert_cmpuint(found_sz, ==, expected_sz);
@@ -100,11 +100,11 @@ test_merr_with_context(void)
     err = merrx(ENOENT, 2); line = __LINE__;
 #ifndef MERR_PLAIN
     expected_sz = (size_t)snprintf(
-        expected, sizeof(expected), "%s:%d: %s (%d): %s (%u)", file, merr_lineno(err),
+        expected, sizeof(expected), "%s:%d: %s (%d): %s (%d)", file, merr_lineno(err),
         strerror(merr_errno(err)), merr_errno(err), ctx_stringify(merr_ctx(err)), merr_ctx(err));
 #else
     expected_sz = (size_t)snprintf(
-        expected, sizeof(expected), "%s (%d): %s (%u)",
+        expected, sizeof(expected), "%s (%d): %s (%d)",
         strerror(merr_errno(err)), merr_errno(err), ctx_stringify(merr_ctx(err)), merr_ctx(err));
 #endif