diff --git a/pw_allocator/BUILD.gn b/pw_allocator/BUILD.gn
index 0d3c7be..6b22f80 100644
--- a/pw_allocator/BUILD.gn
+++ b/pw_allocator/BUILD.gn
@@ -78,7 +78,6 @@
     "$dir_pw_log",
   ]
   sources = [ "freelist_heap.cc" ]
-  sources += public
 }
 
 pw_test_group("tests") {
diff --git a/pw_assert_basic/BUILD.gn b/pw_assert_basic/BUILD.gn
index 12ddf2e..0a64365 100644
--- a/pw_assert_basic/BUILD.gn
+++ b/pw_assert_basic/BUILD.gn
@@ -32,7 +32,6 @@
   ]
   deps = [ ":core" ]
   public = [ "public_overrides/pw_assert_backend/assert_backend.h" ]
-  sources = public
 }
 
 pw_source_set("core") {
@@ -44,7 +43,7 @@
     "$dir_pw_sys_io",
   ]
   public = [ "public/pw_assert_basic/assert_basic.h" ]
-  sources = public + [ "assert_basic.cc" ]
+  sources = [ "assert_basic.cc" ]
 }
 
 pw_doc_group("docs") {
diff --git a/pw_base64/BUILD.gn b/pw_base64/BUILD.gn
index 6fdc1dc..286edb6 100644
--- a/pw_base64/BUILD.gn
+++ b/pw_base64/BUILD.gn
@@ -26,7 +26,6 @@
   public_configs = [ ":default_config" ]
   public = [ "public/pw_base64/base64.h" ]
   sources = [ "base64.cc" ]
-  sources += public
   public_deps = [ "$dir_pw_span" ]
 }
 
diff --git a/pw_bloat/BUILD.gn b/pw_bloat/BUILD.gn
index 8011fc2..7e4f29c 100644
--- a/pw_bloat/BUILD.gn
+++ b/pw_bloat/BUILD.gn
@@ -27,7 +27,7 @@
 pw_source_set("bloat_this_binary") {
   public_configs = [ ":default_config" ]
   public = [ "public/pw_bloat/bloat_this_binary.h" ]
-  sources = [ "bloat_this_binary.cc" ] + public
+  sources = [ "bloat_this_binary.cc" ]
 }
 
 source_set("base_main") {
diff --git a/pw_boot_armv7m/BUILD.gn b/pw_boot_armv7m/BUILD.gn
index 38b3a0e..2e3c6ff 100644
--- a/pw_boot_armv7m/BUILD.gn
+++ b/pw_boot_armv7m/BUILD.gn
@@ -53,7 +53,7 @@
       defines = [ "PW_BOOT_ARMV7M_QEMU_SHUTDOWN=1" ]
     }
     public = [ "public/pw_boot_armv7m/boot.h" ]
-    sources = [ "core_init.c" ] + public
+    sources = [ "core_init.c" ]
   }
 }
 
diff --git a/pw_fuzzer/BUILD.gn b/pw_fuzzer/BUILD.gn
index 61271c3..130a05b 100644
--- a/pw_fuzzer/BUILD.gn
+++ b/pw_fuzzer/BUILD.gn
@@ -73,7 +73,6 @@
     "public/pw_fuzzer/asan_interface.h",
     "public/pw_fuzzer/fuzzed_data_provider.h",
   ]
-  sources = public
   public_deps = [ "$dir_pw_log" ]
 }
 
diff --git a/pw_polyfill/BUILD.gn b/pw_polyfill/BUILD.gn
index e3d40f2..2dcb666 100644
--- a/pw_polyfill/BUILD.gn
+++ b/pw_polyfill/BUILD.gn
@@ -30,7 +30,6 @@
     "public/pw_polyfill/language_features.h",
     "public/pw_polyfill/standard.h",
   ]
-  sources = public
 }
 
 config("overrides_config") {
@@ -63,7 +62,6 @@
     "standard_library_public/pw_polyfill/standard_library/namespace.h",
     "standard_library_public/pw_polyfill/standard_library/type_traits.h",
   ]
-  sources = public
   visibility = [
     ":overrides",
     ":pw_polyfill",
diff --git a/pw_preprocessor/BUILD.gn b/pw_preprocessor/BUILD.gn
index dff5a11..0c43ec0 100644
--- a/pw_preprocessor/BUILD.gn
+++ b/pw_preprocessor/BUILD.gn
@@ -31,7 +31,6 @@
     "public/pw_preprocessor/macro_arg_count.h",
     "public/pw_preprocessor/util.h",
   ]
-  sources = public
 }
 
 pw_doc_group("docs") {
diff --git a/pw_protobuf/BUILD.gn b/pw_protobuf/BUILD.gn
index 99d2270..eab8eaa 100644
--- a/pw_protobuf/BUILD.gn
+++ b/pw_protobuf/BUILD.gn
@@ -43,7 +43,6 @@
     "encoder.cc",
     "find.cc",
   ]
-  sources += public
 }
 
 pw_doc_group("docs") {
diff --git a/pw_status/BUILD.gn b/pw_status/BUILD.gn
index 0522ad2..cfa9cf9 100644
--- a/pw_status/BUILD.gn
+++ b/pw_status/BUILD.gn
@@ -28,7 +28,7 @@
     "public/pw_status/status.h",
     "public/pw_status/status_with_size.h",
   ]
-  sources = [ "status.cc" ] + public
+  sources = [ "status.cc" ]
 }
 
 pw_test_group("tests") {
diff --git a/pw_string/BUILD.gn b/pw_string/BUILD.gn
index c657cee..b1c9108 100644
--- a/pw_string/BUILD.gn
+++ b/pw_string/BUILD.gn
@@ -37,7 +37,6 @@
     "string_builder.cc",
     "type_to_string.cc",
   ]
-  sources += public
   public_deps = [
     "$dir_pw_preprocessor",
     "$dir_pw_span",
diff --git a/pw_trace_tokenized/BUILD.gn b/pw_trace_tokenized/BUILD.gn
index 74843b2..c24e68d 100644
--- a/pw_trace_tokenized/BUILD.gn
+++ b/pw_trace_tokenized/BUILD.gn
@@ -52,7 +52,6 @@
   }
 
   public = [ "public_overrides/pw_trace_backend/trace_backend.h" ]
-  sources = public
 }
 
 pw_test("trace_tokenized_test") {
@@ -113,7 +112,7 @@
     "public/pw_trace_tokenized/trace_callback.h",
     "public/pw_trace_tokenized/trace_tokenized.h",
   ]
-  sources = public + [ "trace.cc" ]
+  sources = [ "trace.cc" ]
 }
 
 pw_doc_group("docs") {
diff --git a/pw_unit_test/BUILD.gn b/pw_unit_test/BUILD.gn
index 5184919..08eae47 100644
--- a/pw_unit_test/BUILD.gn
+++ b/pw_unit_test/BUILD.gn
@@ -38,7 +38,7 @@
     "public/pw_unit_test/framework.h",
     "public_overrides/gtest/gtest.h",
   ]
-  sources = [ "framework.cc" ] + public
+  sources = [ "framework.cc" ]
 }
 
 # Library providing an event handler which outputs human-readable text.
@@ -48,7 +48,7 @@
     "$dir_pw_preprocessor",
   ]
   public = [ "public/pw_unit_test/simple_printing_event_handler.h" ]
-  sources = [ "simple_printing_event_handler.cc" ] + public
+  sources = [ "simple_printing_event_handler.cc" ]
 }
 
 # Library providing a standard desktop main function for the pw_unit_test
@@ -75,7 +75,7 @@
     "$dir_pw_preprocessor",
   ]
   public = [ "public/pw_unit_test/logging_event_handler.h" ]
-  sources = [ "logging_event_handler.cc" ] + public
+  sources = [ "logging_event_handler.cc" ]
 }
 
 pw_source_set("logging_main") {