diff --git a/expected/plpgsql_check_active.out b/expected/plpgsql_check_active.out
index 401c70c..45beb1c 100644
--- a/expected/plpgsql_check_active.out
+++ b/expected/plpgsql_check_active.out
@@ -9422,3 +9422,28 @@ $$ language plpgsql;
 -- should not to crash
 select trace_test(3);
 ERROR:  too late initialization of fmgr_plpgsql_cache
+create table testtable_pure_expr(a int);
+-- detection of not pure expressions
+create or replace function pure_expr()
+returns void as $$
+declare v int;
+begin
+  v := 1
+  delete from testtable_pure_expr where a = 10;
+  raise notice '%', v;
+end;
+$$ language plpgsql;
+-- raise warning
+select * from plpgsql_check_function('pure_expr()');
+                       plpgsql_check_function                       
+--------------------------------------------------------------------
+ warning extra:42601:4:assignment:expression is not pure expression
+ Query: v := 1
+ --          ^
+          delete from testtable_pure_expr where a = 10
+ Detail: there is a possibility of unwanted behave
+ Hint: Maybe you forgot to use a semicolon.
+ Context: at assignment to variable "v" declared on line 2
+(7 rows)
+
+drop table testtable_pure_expr;
diff --git a/expected/plpgsql_check_active_1.out b/expected/plpgsql_check_active_1.out
index dcb6df8..63d524b 100644
--- a/expected/plpgsql_check_active_1.out
+++ b/expected/plpgsql_check_active_1.out
@@ -9424,3 +9424,19 @@ $$ language plpgsql;
 -- should not to crash
 select trace_test(3);
 ERROR:  too late initialization of fmgr_plpgsql_cache
+create table testtable_pure_expr(a int);
+-- detection of not pure expressions
+create or replace function pure_expr()
+returns void as $$
+declare v int;
+begin
+  v := 1
+  delete from testtable_pure_expr where a = 10;
+  raise notice '%', v;
+end;
+$$ language plpgsql;
+ERROR:  syntax error at or near "delete" at character 91
+-- raise warning
+select * from plpgsql_check_function('pure_expr()');
+ERROR:  function "pure_expr()" does not exist
+drop table testtable_pure_expr;
diff --git a/expected/plpgsql_check_active_2.out b/expected/plpgsql_check_active_2.out
index 8bf08ef..cd229de 100644
--- a/expected/plpgsql_check_active_2.out
+++ b/expected/plpgsql_check_active_2.out
@@ -9421,3 +9421,28 @@ $$ language plpgsql;
 -- should not to crash
 select trace_test(3);
 ERROR:  too late initialization of fmgr_plpgsql_cache
+create table testtable_pure_expr(a int);
+-- detection of not pure expressions
+create or replace function pure_expr()
+returns void as $$
+declare v int;
+begin
+  v := 1
+  delete from testtable_pure_expr where a = 10;
+  raise notice '%', v;
+end;
+$$ language plpgsql;
+-- raise warning
+select * from plpgsql_check_function('pure_expr()');
+                       plpgsql_check_function                       
+--------------------------------------------------------------------
+ warning extra:42601:4:assignment:expression is not pure expression
+ Query: v := 1
+ --          ^
+          delete from testtable_pure_expr where a = 10
+ Detail: there is a possibility of unwanted behave
+ Hint: Maybe you forgot to use a semicolon.
+ Context: at assignment to variable "v" declared on line 2
+(7 rows)
+
+drop table testtable_pure_expr;
diff --git a/expected/plpgsql_check_active_3.out b/expected/plpgsql_check_active_3.out
index 4a02142..cb58079 100644
--- a/expected/plpgsql_check_active_3.out
+++ b/expected/plpgsql_check_active_3.out
@@ -9422,3 +9422,28 @@ $$ language plpgsql;
 -- should not to crash
 select trace_test(3);
 ERROR:  too late initialization of fmgr_plpgsql_cache
+create table testtable_pure_expr(a int);
+-- detection of not pure expressions
+create or replace function pure_expr()
+returns void as $$
+declare v int;
+begin
+  v := 1
+  delete from testtable_pure_expr where a = 10;
+  raise notice '%', v;
+end;
+$$ language plpgsql;
+-- raise warning
+select * from plpgsql_check_function('pure_expr()');
+                       plpgsql_check_function                       
+--------------------------------------------------------------------
+ warning extra:42601:4:assignment:expression is not pure expression
+ Query: v := 1
+ --          ^
+          delete from testtable_pure_expr where a = 10
+ Detail: there is a possibility of unwanted behave
+ Hint: Maybe you forgot to use a semicolon.
+ Context: at assignment to variable "v" declared on line 2
+(7 rows)
+
+drop table testtable_pure_expr;
diff --git a/sql/plpgsql_check_active.sql b/sql/plpgsql_check_active.sql
index 27b02c2..fa09c0f 100644
--- a/sql/plpgsql_check_active.sql
+++ b/sql/plpgsql_check_active.sql
@@ -5619,3 +5619,21 @@ $$ language plpgsql;
 \c
 -- should not to crash
 select trace_test(3);
+
+create table testtable_pure_expr(a int);
+
+-- detection of not pure expressions
+create or replace function pure_expr()
+returns void as $$
+declare v int;
+begin
+  v := 1
+  delete from testtable_pure_expr where a = 10;
+  raise notice '%', v;
+end;
+$$ language plpgsql;
+
+-- raise warning
+select * from plpgsql_check_function('pure_expr()');
+
+drop table testtable_pure_expr;
diff --git a/src/check_expr.c b/src/check_expr.c
index 275cc36..1d0a5c4 100644
--- a/src/check_expr.c
+++ b/src/check_expr.c
@@ -17,6 +17,7 @@
 #include "catalog/pg_proc.h"
 #include "catalog/pg_type.h"
 #include "executor/spi_priv.h"
+#include "nodes/nodeFuncs.h"
 #include "optimizer/clauses.h"
 #include "optimizer/optimizer.h"
 #include "parser/parse_node.h"
@@ -440,9 +441,9 @@ check_pure_expr(PLpgSQL_checkstate *cstate, Query *query, char *query_str)
 								ERRCODE_SYNTAX_ERROR, 0,
 								"expression is not pure expression",
 								"there is a possibility of unwanted behave",
-								NULL,
+								"Maybe you forgot to use a semicolon.",
 								PLPGSQL_CHECK_WARNING_EXTRA,
-								0, query_str, NULL);
+								exprLocation(query->targetList), query_str, NULL);
 	}
 }