diff --git a/contrib/auth_delay/auth_delay.c b/contrib/auth_delay/auth_delay.c
index 5820ac328d..d11dd1e416 100644
--- a/contrib/auth_delay/auth_delay.c
+++ b/contrib/auth_delay/auth_delay.c
@@ -67,6 +67,9 @@ _PG_init(void)
 							NULL,
 							NULL,
 							NULL);
+
+	EmitWarningsOnPlaceholders("auth_delay");
+
 	/* Install Hooks */
 	original_client_auth_hook = ClientAuthentication_hook;
 	ClientAuthentication_hook = auth_delay_checks;
diff --git a/contrib/pg_trgm/trgm_op.c b/contrib/pg_trgm/trgm_op.c
index fb38135f7a..0407c7dd64 100644
--- a/contrib/pg_trgm/trgm_op.c
+++ b/contrib/pg_trgm/trgm_op.c
@@ -100,6 +100,8 @@ _PG_init(void)
 							 NULL,
 							 NULL,
 							 NULL);
+
+	EmitWarningsOnPlaceholders("pg_trgm");
 }
 
 /*
diff --git a/contrib/postgres_fdw/option.c b/contrib/postgres_fdw/option.c
index 48c7417e6e..36555398ec 100644
--- a/contrib/postgres_fdw/option.c
+++ b/contrib/postgres_fdw/option.c
@@ -469,4 +469,6 @@ _PG_init(void)
 							   NULL,
 							   NULL,
 							   NULL);
+
+	EmitWarningsOnPlaceholders("postgres_fdw");
 }
diff --git a/contrib/sepgsql/hooks.c b/contrib/sepgsql/hooks.c
index 19a3ffb7ff..44a09c35a7 100644
--- a/contrib/sepgsql/hooks.c
+++ b/contrib/sepgsql/hooks.c
@@ -455,6 +455,8 @@ _PG_init(void)
 							 NULL,
 							 NULL);
 
+	EmitWarningsOnPlaceholders("sepgsql");
+
 	/* Initialize userspace access vector cache */
 	sepgsql_avc_init();
 
diff --git a/src/pl/tcl/pltcl.c b/src/pl/tcl/pltcl.c
index e11837559d..1389aa0943 100644
--- a/src/pl/tcl/pltcl.c
+++ b/src/pl/tcl/pltcl.c
@@ -474,6 +474,8 @@ _PG_init(void)
 							   PGC_SUSET, 0,
 							   NULL, NULL, NULL);
 
+	EmitWarningsOnPlaceholders("pltclu");
+
 	pltcl_pm_init_done = true;
 }