Various bug fixes:

  - Duplicate parameters/variables, conditions and cursors (not allowed).
  - ITERATE in labelled BEGIN-END (not allowed).
  - Missing SQLSTATE [VALUE] keywords in CONDITION/HANDLER declaration (added).
  - Empty BEGIN-END (now allowed).
  - End label (now optional).

include/mysqld_error.h

@@ -323,4 +323,5 @@
 #define ER_SP_UNDECLARED_VAR 1304
 #define ER_SP_WRONG_NO_OF_FETCH_ARGS 1305
 #define ER_SP_FETCH_NO_DATA 1306
-#define ER_ERROR_MESSAGES 307
+#define ER_SP_DUP_THING 1307
+#define ER_ERROR_MESSAGES 308

mysql-test/r/sp-error.result

@@ -47,6 +47,11 @@ iterate bar;
 end loop;
 ERROR HY000: ITERATE with no matching label: bar
 create procedure foo()
+foo: begin
+iterate foo;
+end;
+ERROR HY000: ITERATE with no matching label: foo
+create procedure foo()
 foo: loop
 foo: loop
 set @x=2;
@@ -219,4 +224,30 @@ end;
 call p();
 ERROR HY000: Wrong number of FETCH variables
 drop procedure p;
+create procedure p(in x int, x char(10))
+begin
+end;
+ERROR HY000: Duplicate parameter: x
+create function p(x int, x char(10))
+begin
+end;
+ERROR HY000: Duplicate parameter: x
+create procedure p()
+begin
+declare x float;
+declare x int;
+end;
+ERROR HY000: Duplicate parameter: x
+create procedure p()
+begin
+declare c condition for 1064;
+declare c condition for 1065;
+end;
+ERROR HY000: Duplicate condition: c
+create procedure p()
+begin
+declare c cursor for select * from t1;
+declare c cursor for select field from t1;
+end;
+ERROR HY000: Duplicate cursor: c
 drop table t1;

mysql-test/r/sp.result

@@ -36,6 +36,20 @@ select * from t1;
 id	data
 bar	666
 delete from t1;
+create procedure empty()
+begin
+end;
+call empty();
+drop procedure empty;
+create procedure scope(a int, b float)
+begin
+declare b int;
+declare c float;
+begin
+declare c int;
+end;
+end;
+drop procedure scope;
 create procedure two(x1 char(16), x2 char(16), y int)
 begin
 insert into test.t1 values (x1, y);
@@ -256,7 +270,7 @@ insert into test.t1 values ("d", x);
 set x = x-1;
 leave hmm;
 insert into test.t1 values ("x", x);
-end while hmm;
+end while;
 call d(3);
 select * from t1;
 id	data
@@ -335,6 +349,21 @@ h1	1
 h?	17
 delete from t1;
 drop procedure h;
+create procedure i(x int)
+foo:
+begin
+if x = 0 then
+leave foo;
+end if;
+insert into test.t1 values ("i", x);
+end foo;
+call i(0);
+call i(3);
+select * from t1;
+id	data
+i	3
+delete from t1;
+drop procedure i;
 create procedure into_test(x char(16), y int)
 begin
 insert into test.t1 values (x, y);
@@ -461,6 +490,8 @@ create procedure hndlr1(val int)
 begin
 declare x int default 0;
 declare foo condition for 1146;
+declare bar condition for sqlstate '42S98';        # Just for testing syntax
+declare zip condition for sqlstate value '42S99';  # Just for testing syntax
 declare continue handler for foo set x = 1;
 insert into test.t666 values ("hndlr1", val);   # Non-existing table
 if (x) then
@@ -477,7 +508,7 @@ create procedure hndlr2(val int)
 begin
 declare x int default 0;
 begin
-declare exit handler for '42S02' set x = 1;
+declare exit handler for sqlstate '42S02' set x = 1;
 insert into test.t666 values ("hndlr2", val); # Non-existing table
 end;
 insert into test.t1 values ("hndlr2", x);
@@ -744,7 +775,7 @@ end if;
 set s = s+1;
 end;
 end if;
-end loop again;
+end loop;
 end;
 create procedure ip(m int unsigned)
 begin

mysql-test/t/sp-error.test

@@ -74,6 +74,11 @@ create procedure foo()
 foo: loop
   iterate bar;
 end loop|
+--error 1285
+create procedure foo()
+foo: begin
+  iterate foo;
+end|
 
 # Redefining label
 --error 1286 
@@ -298,6 +303,33 @@ end|
 call p()|
 drop procedure p|
 
+--error 1307
+create procedure p(in x int, x char(10))
+begin
+end|
+--error 1307
+create function p(x int, x char(10))
+begin
+end|
+--error 1307
+create procedure p()
+begin
+  declare x float;
+  declare x int;
+end|
+--error 1307
+create procedure p()
+begin
+  declare c condition for 1064;
+  declare c condition for 1065;
+end|
+--error 1307
+create procedure p()
+begin
+  declare c cursor for select * from t1;
+  declare c cursor for select field from t1;
+end|
+
 drop table t1|
 
 delimiter ;|

mysql-test/t/sp.test

@@ -59,6 +59,28 @@ delete from t1;
 # Now for multiple statements...
 delimiter |;
 
+# Empty statement
+create procedure empty()
+begin
+end|
+
+call empty()|
+drop procedure empty|
+
+# Scope test. This is legal (warnings might be possible in the future,
+# but for the time being, we just accept it).
+create procedure scope(a int, b float)
+begin
+  declare b int;
+  declare c float;
+
+  begin
+    declare c int;
+  end;
+end|
+
+drop procedure scope|
+
 # Two statements.
 create procedure two(x1 char(16), x2 char(16), y int)
 begin
@@ -313,7 +335,7 @@ hmm: while x > 0 do
   set x = x-1;
   leave hmm;
   insert into test.t1 values ("x", x);
-end while hmm|
+end while|
 
 call d(3)|
 select * from t1|
@@ -393,6 +415,23 @@ delete from t1|
 drop procedure h|
 
 
+# It's actually possible to LEAVE a BEGIN-END block
+create procedure i(x int)
+foo:
+begin
+  if x = 0 then
+    leave foo;
+  end if;
+  insert into test.t1 values ("i", x);
+end foo|
+
+call i(0)|
+call i(3)|
+select * from t1|
+delete from t1|
+drop procedure i|
+
+
 # SELECT INTO local variables
 create procedure into_test(x char(16), y int)
 begin
@@ -543,6 +582,8 @@ create procedure hndlr1(val int)
 begin
   declare x int default 0;
   declare foo condition for 1146;
+  declare bar condition for sqlstate '42S98';        # Just for testing syntax
+  declare zip condition for sqlstate value '42S99';  # Just for testing syntax
   declare continue handler for foo set x = 1;
 
   insert into test.t666 values ("hndlr1", val);   # Non-existing table
@@ -561,7 +602,7 @@ begin
   declare x int default 0;
 
   begin
-    declare exit handler for '42S02' set x = 1;
+    declare exit handler for sqlstate '42S02' set x = 1;
 
     insert into test.t666 values ("hndlr2", val); # Non-existing table
   end;
@@ -864,7 +905,7 @@ begin
         set s = s+1;
       end;
     end if;
-  end loop again;
+  end loop;
 end|
 
 create procedure ip(m int unsigned)

sql/lex.h

@@ -386,6 +386,7 @@ static SYMBOL symbols[] = {
   { "SPATIAL",		SYM(SPATIAL_SYM),0,0},
   { "SPECIFIC",		SYM(SPECIFIC_SYM),0,0},
   { "SQLEXCEPTION",	SYM(SQLEXCEPTION_SYM),0,0},
+  { "SQLSTATE",         SYM(SQLSTATE_SYM),0,0},
   { "SQLWARNING",	SYM(SQLWARNING_SYM),0,0},
   { "SQL_BIG_RESULT",	SYM(SQL_BIG_RESULT),0,0},
   { "SQL_BUFFER_RESULT", SYM(SQL_BUFFER_RESULT),0,0},

sql/share/czech/errmsg.txt

@@ -319,3 +319,4 @@ character-set=latin2
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/danish/errmsg.txt

@@ -313,3 +313,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/dutch/errmsg.txt

@@ -321,3 +321,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/english/errmsg.txt

@@ -310,3 +310,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/estonian/errmsg.txt

@@ -315,3 +315,4 @@ character-set=latin7
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/french/errmsg.txt

@@ -310,3 +310,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/german/errmsg.txt

@@ -322,3 +322,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/greek/errmsg.txt

@@ -310,3 +310,4 @@ character-set=greek
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/hungarian/errmsg.txt

@@ -312,3 +312,4 @@ character-set=latin2
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/italian/errmsg.txt

@@ -310,3 +310,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/japanese/errmsg.txt

@@ -312,3 +312,4 @@ character-set=ujis
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/korean/errmsg.txt

@@ -310,3 +310,4 @@ character-set=euckr
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/norwegian-ny/errmsg.txt

@@ -312,3 +312,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/norwegian/errmsg.txt

@@ -312,3 +312,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/polish/errmsg.txt

@@ -314,3 +314,4 @@ character-set=latin2
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/portuguese/errmsg.txt

@@ -311,3 +311,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/romanian/errmsg.txt

@@ -314,3 +314,4 @@ character-set=latin2
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/russian/errmsg.txt

@@ -312,3 +312,4 @@ character-set=koi8r
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/serbian/errmsg.txt

@@ -305,3 +305,4 @@ character-set=cp1250
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/slovak/errmsg.txt

@@ -318,3 +318,4 @@ character-set=latin2
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/spanish/errmsg.txt

@@ -312,3 +312,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/swedish/errmsg.txt

@@ -310,3 +310,4 @@ character-set=latin1
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/share/ukrainian/errmsg.txt

@@ -315,3 +315,4 @@ character-set=koi8u
 "Undeclared variable: %s"
 "Wrong number of FETCH variables"
 "No data to FETCH"
+"Duplicate %s: %s"

sql/sp_pcontext.cc

@@ -32,6 +32,7 @@ sp_pcontext::sp_pcontext()
   VOID(my_init_dynamic_array(&m_pvar, sizeof(sp_pvar_t *), 16, 8));
   VOID(my_init_dynamic_array(&m_cond, sizeof(sp_cond_type_t *), 16, 8));
   VOID(my_init_dynamic_array(&m_cursor, sizeof(LEX_STRING), 16, 8));
+  VOID(my_init_dynamic_array(&m_scopes, sizeof(sp_scope_t), 16, 8));
   m_label.empty();
 }
 
@@ -41,23 +42,52 @@ sp_pcontext::destroy()
   delete_dynamic(&m_pvar);
   delete_dynamic(&m_cond);
   delete_dynamic(&m_cursor);
+  delete_dynamic(&m_scopes);
   m_label.empty();
 }
 
+void
+sp_pcontext::push_scope()
+{
+  sp_scope_t s;
+
+  s.vars= m_pvar.elements;
+  s.conds= m_cond.elements;
+  s.curs= m_cursor.elements;
+  insert_dynamic(&m_scopes, (gptr)&s);
+}
+
+void
+sp_pcontext::pop_scope()
+{
+  (void)pop_dynamic(&m_scopes);
+}
+
 
 /* This does a linear search (from newer to older variables, in case
 ** we have shadowed names).
 ** It's possible to have a more efficient allocation and search method,
 ** but it might not be worth it. The typical number of parameters and
 ** variables will in most cases be low (a handfull).
-** And this is only called during parsing.
+** ...and, this is only called during parsing.
 */
 sp_pvar_t *
-sp_pcontext::find_pvar(LEX_STRING *name)
+sp_pcontext::find_pvar(LEX_STRING *name, my_bool scoped)
 {
   uint i = m_pvar.elements;
+  uint limit;
 
-  while (i-- > 0)
+  if (! scoped || m_scopes.elements == 0)
+    limit= 0;
+  else
+  {
+    sp_scope_t s;
+
+    get_dynamic(&m_scopes, (gptr)&s, m_scopes.elements-1);
+    limit= s.vars;
+  }
+      
+  while (i-- > limit)
   {
     sp_pvar_t *p;
 
@@ -101,6 +131,7 @@ sp_pcontext::push_label(char *name, uint ip)
   {
     lab->name= name;
     lab->ip= ip;
+    lab->isbegin= FALSE;
     m_label.push_front(lab);
   }
   return lab;
@@ -137,11 +168,22 @@ sp_pcontext::push_cond(LEX_STRING *name, sp_cond_type_t *val)
  * See comment for find_pvar() above
  */
 sp_cond_type_t *
-sp_pcontext::find_cond(LEX_STRING *name)
+sp_pcontext::find_cond(LEX_STRING *name, my_bool scoped)
 {
   uint i = m_cond.elements;
+  uint limit;
+
+  if (! scoped || m_scopes.elements == 0)
+    limit= 0;
+  else
+  {
+    sp_scope_t s;
+
+    get_dynamic(&m_scopes, (gptr)&s, m_scopes.elements-1);
+    limit= s.conds;
+  }
       
-  while (i-- > 0)
+  while (i-- > limit)
   {
     sp_cond_t *p;
 
@@ -172,11 +214,22 @@ sp_pcontext::push_cursor(LEX_STRING *name)
  * See comment for find_pvar() above
  */
 my_bool
-sp_pcontext::find_cursor(LEX_STRING *name, uint *poff)
+sp_pcontext::find_cursor(LEX_STRING *name, uint *poff, my_bool scoped)
 {
   uint i = m_cursor.elements;
+  uint limit;
+
+  if (! scoped || m_scopes.elements == 0)
+    limit= 0;
+  else
+  {
+    sp_scope_t s;
+
+    get_dynamic(&m_scopes, (gptr)&s, m_scopes.elements-1);
+    limit= s.curs;
+  }
       
-  while (i-- > 0)
+  while (i-- > limit)
   {
     LEX_STRING n;
 

sql/sp_pcontext.h

@@ -42,6 +42,7 @@ typedef struct sp_label
 {
   char *name;
   uint ip;			// Instruction index
+  my_bool isbegin;		// For ITERATE error checking
 } sp_label_t;
 
 typedef struct sp_cond_type
@@ -57,6 +58,11 @@ typedef struct sp_cond
   sp_cond_type_t *val;
 } sp_cond_t;
 
+typedef struct sp_scope
+{
+  uint vars, conds, curs;
+} sp_scope_t;
+
 class sp_pcontext : public Sql_alloc
 {
   sp_pcontext(const sp_pcontext &); /* Prevent use of these */
@@ -70,6 +76,13 @@ class sp_pcontext : public Sql_alloc
   void
   destroy();
 
+  // For error checking of duplicate things
+  void
+  push_scope();
+
+  void
+  pop_scope();
+
   //
   // Parameters and variables
   //
@@ -130,7 +143,7 @@ class sp_pcontext : public Sql_alloc
 
   // Find by name
   sp_pvar_t *
-  find_pvar(LEX_STRING *name);
+  find_pvar(LEX_STRING *name, my_bool scoped=0);
 
   // Find by index
   sp_pvar_t *
@@ -182,7 +195,7 @@ class sp_pcontext : public Sql_alloc
   }
 
   sp_cond_type_t *
-  find_cond(LEX_STRING *name);
+  find_cond(LEX_STRING *name, my_bool scoped=0);
 
   //
   // Handlers
@@ -208,7 +221,7 @@ class sp_pcontext : public Sql_alloc
   push_cursor(LEX_STRING *name);
 
   my_bool
-  find_cursor(LEX_STRING *name, uint *poff);
+  find_cursor(LEX_STRING *name, uint *poff, my_bool scoped=0);
 
   inline void
   pop_cursor(uint num)
@@ -233,6 +246,7 @@ private:
   DYNAMIC_ARRAY m_pvar;		// Parameters/variables
   DYNAMIC_ARRAY m_cond;		// Conditions
   DYNAMIC_ARRAY m_cursor;	// Cursors
+  DYNAMIC_ARRAY m_scopes;	// For error checking
 
   List<sp_label_t> m_label;	// The label list
 

sql/sql_yacc.yy

@@ -371,6 +371,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 %token	SPATIAL_SYM
 %token  SPECIFIC_SYM
 %token  SQLEXCEPTION_SYM
+%token  SQLSTATE_SYM
 %token  SQLWARNING_SYM
 %token  SSL_SYM
 %token	STARTING
@@ -618,7 +619,7 @@ bool my_yyoverflow(short **a, YYSTYPE **b,int *yystacksize);
 	ULONGLONG_NUM field_ident select_alias ident ident_or_text
         UNDERSCORE_CHARSET IDENT_sys TEXT_STRING_sys TEXT_STRING_literal
 	NCHAR_STRING opt_component
-        SP_FUNC ident_or_spfunc
+        SP_FUNC ident_or_spfunc sp_opt_label
 
 %type <lex_str_ptr>
 	opt_table_alias
@@ -1149,7 +1150,15 @@ sp_fdparams:
 sp_fdparam:
 	  ident type sp_opt_locator
 	  {
-	    Lex->spcont->push_pvar(&$1, (enum enum_field_types)$2, sp_param_in);
+	    LEX *lex= Lex;
+	    sp_pcontext *spc= lex->spcont;
+
+	    if (spc->find_pvar(&$1, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "parameter", $1.str);
+	      YYABORT;
+	    }
+	    spc->push_pvar(&$1, (enum enum_field_types)$2, sp_param_in);
 	  }
 	;
 
@@ -1167,8 +1176,15 @@ sp_pdparams:
 sp_pdparam:
 	  sp_opt_inout ident type sp_opt_locator
 	  {
-	    Lex->spcont->push_pvar(&$2,
-	                           (enum enum_field_types)$3,
+	    LEX *lex= Lex;
+	    sp_pcontext *spc= lex->spcont;
+
+	    if (spc->find_pvar(&$2, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "parameter", $2.str);
+	      YYABORT;
+	    }
+	    spc->push_pvar(&$2, (enum enum_field_types)$3,
 			   (sp_param_mode_t)$1);
 	  }
 	;
@@ -1186,7 +1202,7 @@ sp_opt_locator:
 	;
 
 sp_proc_stmts:
-	  sp_proc_stmt ';'
+	  /* Empty */ {}
 	| sp_proc_stmts sp_proc_stmt ';'
 	;
 
@@ -1231,6 +1247,14 @@ sp_decl:
 	  }
 	| DECLARE_SYM ident CONDITION_SYM FOR_SYM sp_cond
 	  {
+	    LEX *lex= Lex;
+	    sp_pcontext *spc= lex->spcont;
+
+	    if (spc->find_cond(&$2, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "condition", $2.str);
+	      YYABORT;
+	    }
 	    YYTHD->lex->spcont->push_cond(&$2, $5);
 	    $$.vars= $$.hndlrs= $$.curs= 0;
 	    $$.conds= 1;
@@ -1272,8 +1296,16 @@ sp_decl:
 	  {
 	    LEX *lex= Lex;
 	    sp_head *sp= lex->sphead;
-	    sp_instr_cpush *i= new sp_instr_cpush(sp->instructions(), $5);
+	    sp_pcontext *spc= lex->spcont;
+	    uint offp;
+	    sp_instr_cpush *i;
 
+	    if (spc->find_cursor(&$2, &offp, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "cursor", $2.str);
+	      YYABORT;
+	    }
+            i= new sp_instr_cpush(sp->instructions(), $5);
 	    sp->add_instr(i);
 	    lex->spcont->push_cursor(&$2);
 	    $$.vars= $$.conds= $$.hndlrs= 0;
@@ -1344,18 +1376,23 @@ sp_cond:
 	    $$->type= sp_cond_type_t::number;
 	    $$->mysqlerr= $1;
 	  }
-	| TEXT_STRING_literal
+	| SQLSTATE_SYM opt_value TEXT_STRING_literal
 	  {		/* SQLSTATE */
-	    uint len= ($1.length < sizeof($$->sqlstate)-1 ?
-                       $1.length : sizeof($$->sqlstate)-1);
+	    uint len= ($3.length < sizeof($$->sqlstate)-1 ?
+                       $3.length : sizeof($$->sqlstate)-1);
 
 	    $$= (sp_cond_type_t *)YYTHD->alloc(sizeof(sp_cond_type_t));
 	    $$->type= sp_cond_type_t::state;
-	    memcpy($$->sqlstate, $1.str, len);
+	    memcpy($$->sqlstate, $3.str, len);
 	    $$->sqlstate[len]= '\0';
 	  }
 	;
 
+opt_value:
+	  /* Empty */  {}
+	| VALUE_SYM    {}
+	;
+
 sp_hcond:
 	  sp_cond
 	  {
@@ -1390,12 +1427,28 @@ sp_hcond:
 sp_decl_idents:
 	  ident
 	  {
-	    Lex->spcont->push_pvar(&$1, (enum_field_types)0, sp_param_in);
+	    LEX *lex= Lex;
+	    sp_pcontext *spc= lex->spcont;
+
+	    if (spc->find_pvar(&$1, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "parameter", $1.str);
+	      YYABORT;
+	    }
+	    spc->push_pvar(&$1, (enum_field_types)0, sp_param_in);
 	    $$= 1;
 	  }
 	| sp_decl_idents ',' ident
 	  {
-	    Lex->spcont->push_pvar(&$3, (enum_field_types)0, sp_param_in);
+	    LEX *lex= Lex;
+	    sp_pcontext *spc= lex->spcont;
+
+	    if (spc->find_pvar(&$3, TRUE))
+	    {
+	      net_printf(YYTHD, ER_SP_DUP_THING, "parameter", $3.str);
+	      YYABORT;
+	    }
+	    spc->push_pvar(&$3, (enum_field_types)0, sp_param_in);
 	    $$= $1 + 1;
 	  }
 	;
@@ -1532,7 +1585,7 @@ sp_proc_stmt:
 	    LEX *lex= Lex;
 	    sp_label_t *lab= lex->spcont->find_label($2.str);
 
-	    if (! lab)
+	    if (! lab || lab->isbegin)
 	    {
 	      net_printf(YYTHD, ER_SP_LILABEL_MISMATCH, "ITERATE", $2.str);
 	      YYABORT;
@@ -1736,9 +1789,12 @@ sp_labeled_control:
 	                              lex->sphead->instructions());
 	    }
 	  }
-	  sp_unlabeled_control IDENT
+	  sp_unlabeled_control sp_opt_label
 	  {
 	    LEX *lex= Lex;
+
+	    if ($5.str)
+	    {
 	      sp_label_t *lab= lex->spcont->find_label($5.str);
 
 	      if (!lab ||
@@ -1747,21 +1803,29 @@ sp_labeled_control:
 	        net_printf(YYTHD, ER_SP_LABEL_MISMATCH, $5.str);
 	        YYABORT;
 	      }
-	    else
-	    {
-	      lex->spcont->pop_label();
-	      lex->sphead->backpatch(lab);
 	    }
+	    lex->sphead->backpatch(lex->spcont->pop_label());
 	  }
 	;
 
+sp_opt_label:
+	  /* Empty  */
+	  { $$.str= NULL; $$.length= 0; }
+	| IDENT
+	  { $$= $1; }
+	;
+
 sp_unlabeled_control:
 	  BEGIN_SYM
 	  { /* QQ This is just a dummy for grouping declarations and statements
 	       together. No [[NOT] ATOMIC] yet, and we need to figure out how
 	       make it coexist with the existing BEGIN COMMIT/ROLLBACK. */
+	    LEX *lex= Lex;
+	    sp_label_t *lab= lex->spcont->last_label();
 
-            Lex->spcont->push_label((char *)"", 0); /* For end of block */
+	    lab->isbegin= TRUE;
+	    /* Scope duplicate checking */
+	    lex->spcont->push_scope();
 	  }
 	  sp_decls
 	  sp_proc_stmts
@@ -1771,7 +1835,7 @@ sp_unlabeled_control:
 	    sp_head *sp= lex->sphead;
 	    sp_pcontext *ctx= lex->spcont;
 
-  	    sp->backpatch(ctx->pop_label());
+  	    sp->backpatch(ctx->last_label());	/* We always has a label */
 	    ctx->pop_pvar($3.vars);
 	    ctx->pop_cond($3.conds);
 	    ctx->pop_cursor($3.curs);
@@ -1779,6 +1843,7 @@ sp_unlabeled_control:
 	      sp->add_instr(new sp_instr_hpop(sp->instructions(),$3.hndlrs));
 	    if ($3.curs)
 	      sp->add_instr(new sp_instr_cpop(sp->instructions(), $3.curs));
+	    ctx->pop_scope();
 	  }
 	| LOOP_SYM
 	  sp_proc_stmts END LOOP_SYM