diff --git a/src/pl/plpgsql/src/pl_comp.c b/src/pl/plpgsql/src/pl_comp.c
index 028013f..1bec949 100644
--- a/src/pl/plpgsql/src/pl_comp.c
+++ b/src/pl/plpgsql/src/pl_comp.c
@@ -424,10 +424,6 @@ do_compile(FunctionCallInfo fcinfo,
 				if (argvariable->dtype == PLPGSQL_DTYPE_VAR)
 				{
 					argitemtype = PLPGSQL_NSTYPE_VAR;
-					/* input argument vars are forced to be CONSTANT */
-					if (argmode == PROARGMODE_IN ||
-						argmode == PROARGMODE_VARIADIC)
-						((PLpgSQL_var *) argvariable)->isconst = true;
 				}
 				else
 				{
diff --git a/src/test/regress/expected/plpgsql.out b/src/test/regress/expected/plpgsql.out
index 0446f51..e4109d8 100644
--- a/src/test/regress/expected/plpgsql.out
+++ b/src/test/regress/expected/plpgsql.out
@@ -3808,3 +3808,24 @@ NOTICE:  foo\bar!baz
 (1 row)
 
 drop function strtest();
+create or replace function param_assign_test(a int, val int) returns void as $$
+begin
+  a := val;
+end
+$$ language plpgsql;
+create or replace function param_assign_test2() returns void as $$
+declare a int := 1;
+begin
+  perform param_assign_test(a, 2);
+  raise notice '% should be 1', a;
+end
+$$ language plpgsql;
+select param_assign_test2();
+NOTICE:  1 should be 1
+ param_assign_test2 
+--------------------
+ 
+(1 row)
+
+drop function param_assign_test(int, int);
+drop function param_assign_test2();
diff --git a/src/test/regress/sql/plpgsql.sql b/src/test/regress/sql/plpgsql.sql
index 3dcfc9e..1b982a9 100644
--- a/src/test/regress/sql/plpgsql.sql
+++ b/src/test/regress/sql/plpgsql.sql
@@ -3049,3 +3049,22 @@ $$ language plpgsql;
 select strtest();
 
 drop function strtest();
+
+create or replace function param_assign_test(a int, val int) returns void as $$
+begin
+  a := val;
+end
+$$ language plpgsql;
+
+create or replace function param_assign_test2() returns void as $$
+declare a int := 1;
+begin
+  perform param_assign_test(a, 2);
+  raise notice '% should be 1', a;
+end
+$$ language plpgsql;
+
+select param_assign_test2();
+
+drop function param_assign_test(int, int);
+drop function param_assign_test2();