diff --git a/Makefile b/Makefile
index 132fe29cc..bb64a104e 100644
--- a/Makefile
+++ b/Makefile
@@ -92,7 +92,7 @@ ifdef HOST_WINDOWS
   GLOBAL_LDFLAGS += -Wl,--export-all-symbols
 endif
 
-GLOBAL_CXXFLAGS += -g -Wall -Wdeprecated-copy -Wignored-qualifiers -Wimplicit-fallthrough -include $(buildprefix)config.h -std=c++2a -I src
+GLOBAL_CXXFLAGS += -g -Wall -Wdeprecated-copy -Wignored-qualifiers -Wimplicit-fallthrough -Werror=unused-result -include $(buildprefix)config.h -std=c++2a -I src
 
 # Include the main lib, causing rules to be defined
 
diff --git a/src/libfetchers/meson.build b/src/libfetchers/meson.build
index cab8d63eb..d7975ac65 100644
--- a/src/libfetchers/meson.build
+++ b/src/libfetchers/meson.build
@@ -58,6 +58,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
diff --git a/src/libstore/meson.build b/src/libstore/meson.build
index a605b43e1..d9237c55a 100644
--- a/src/libstore/meson.build
+++ b/src/libstore/meson.build
@@ -164,6 +164,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
diff --git a/src/libutil-c/meson.build b/src/libutil-c/meson.build
index a2b020818..5de288e18 100644
--- a/src/libutil-c/meson.build
+++ b/src/libutil-c/meson.build
@@ -34,6 +34,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
diff --git a/src/libutil/meson.build b/src/libutil/meson.build
index 9d0b28539..099c0c65f 100644
--- a/src/libutil/meson.build
+++ b/src/libutil/meson.build
@@ -143,6 +143,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
diff --git a/src/perl/meson.build b/src/perl/meson.build
index 06abb4f2e..5fe7e1e28 100644
--- a/src/perl/meson.build
+++ b/src/perl/meson.build
@@ -23,11 +23,14 @@ nix_perl_conf.set('PACKAGE_VERSION', meson.project_version())
 # set error arguments
 #-------------------------------------------------
 error_args = [
+  '-Werror=unused-result',
+  '-Wdeprecated-copy',
+  '-Wdeprecated-declarations',
+  '-Wignored-qualifiers',
   '-Wno-pedantic',
   '-Wno-non-virtual-dtor',
   '-Wno-unused-parameter',
   '-Wno-variadic-macros',
-  '-Wdeprecated-declarations',
   '-Wno-missing-field-initializers',
   '-Wno-unknown-warning-option',
   '-Wno-unused-variable',
diff --git a/tests/unit/libutil-support/meson.build b/tests/unit/libutil-support/meson.build
index 5912c00e0..c0345a6ee 100644
--- a/tests/unit/libutil-support/meson.build
+++ b/tests/unit/libutil-support/meson.build
@@ -28,6 +28,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked
diff --git a/tests/unit/libutil/meson.build b/tests/unit/libutil/meson.build
index 56147686b..cc13c4364 100644
--- a/tests/unit/libutil/meson.build
+++ b/tests/unit/libutil/meson.build
@@ -34,6 +34,7 @@ add_project_arguments(
   '-Wimplicit-fallthrough',
   '-Werror=switch',
   '-Werror=switch-enum',
+  '-Werror=unused-result',
   '-Wdeprecated-copy',
   '-Wignored-qualifiers',
   # Enable assertions in libstdc++ by default. Harmless on libc++. Benchmarked