From 106280bb6293833350bd478c3bc021d93397ecb8 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Wed, 24 Jun 2020 21:44:23 +0800
Subject: [PATCH 01/10] Fix enum increments `*= 1` and `<<= 0` working as `+=
 1`

---
 source/compiler/sc1.c                     | 33 +++++----
 source/compiler/tests/enum_increment.meta |  5 ++
 source/compiler/tests/enum_increment.pwn  | 86 +++++++++++++++++++++++
 3 files changed, 110 insertions(+), 14 deletions(-)
 create mode 100644 source/compiler/tests/enum_increment.meta
 create mode 100644 source/compiler/tests/enum_increment.pwn

diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index 41084d1f..21a2b56c 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -2928,7 +2928,8 @@ static void decl_enum(int vclass,int fstatic)
   cell val,value,size;
   char *str;
   int tag,explicittag;
-  cell increment,multiplier;
+  int inctok;
+  cell increment;
   constvalue_root *enumroot=NULL;
   symbol *enumsym=NULL;
   short filenum;
@@ -2958,18 +2959,18 @@ static void decl_enum(int vclass,int fstatic)
     enumname[0]='\0';
   } /* if */
 
-  /* get increment and multiplier */
+  /* get the increment */
   increment=1;
-  multiplier=1;
+  inctok=taADD;
   if (matchtoken('(')) {
-    if (matchtoken(taADD)) {
+    int tok=lex(&val,&str);
+    if (tok==taADD || tok==taMULT || tok==taSHL) {
+      inctok=tok;
       constexpr(&increment,NULL,NULL);
-    } else if (matchtoken(taMULT)) {
-      constexpr(&multiplier,NULL,NULL);
-    } else if (matchtoken(taSHL)) {
-      constexpr(&val,NULL,NULL);
-      while (val-->0)
-        multiplier*=2;
+      if (tok==taSHL && increment<0)
+        increment=0;
+    } else {
+      lexpush();
     } /* if */
     needtoken(')');
   } /* if */
@@ -3005,7 +3006,7 @@ static void decl_enum(int vclass,int fstatic)
     } else {
       constname[0]='\0';
     } /* if */
-    size=increment;                     /* default increment of 'val' */
+    size=(inctok==taADD) ? increment : 1;/* default increment of 'val' */
     fieldtag=0;                         /* default field tag */
     if (matchtoken('[')) {
       constexpr(&size,&fieldtag,NULL);  /* get size */
@@ -3027,6 +3028,8 @@ static void decl_enum(int vclass,int fstatic)
     sym->parent=enumsym;
     if (enumsym)
       enumsym->child=sym;
+    if (vclass==sLOCAL)
+      sym->compound=nestlevel;
 
     if (fstatic)
       sym->fnumber=filenum;
@@ -3036,10 +3039,12 @@ static void decl_enum(int vclass,int fstatic)
       sym->usage |= uENUMFIELD;
       append_constval(enumroot,constname,value,tag);
     } /* if */
-    if (multiplier==1)
+    if (inctok==taADD)
       value+=size;
-    else
-      value*=size*multiplier;
+    else if (inctok==taMULT)
+      value*=(size*increment);
+    else // taSHL
+      value*=(size << increment);
   } while (matchtoken(','));
   needtoken('}');       /* terminates the constant list */
   matchtoken(';');      /* eat an optional ; */
diff --git a/source/compiler/tests/enum_increment.meta b/source/compiler/tests/enum_increment.meta
new file mode 100644
index 00000000..bfdf2528
--- /dev/null
+++ b/source/compiler/tests/enum_increment.meta
@@ -0,0 +1,5 @@
+{
+  'test_type': 'output_check',
+  'errors': """
+  """
+}
diff --git a/source/compiler/tests/enum_increment.pwn b/source/compiler/tests/enum_increment.pwn
new file mode 100644
index 00000000..c549d713
--- /dev/null
+++ b/source/compiler/tests/enum_increment.pwn
@@ -0,0 +1,86 @@
+#pragma option -d1 // TODO: Remove this line when #544 is merged
+
+main()
+{
+	enum e1
+	{
+		e1Elem1[3],
+		e1Elem2,
+		e1Elem3
+	};
+	new arr1[e1];
+	#pragma unused arr1
+	#assert sizeof arr1[e1Elem1] == 3
+	#assert sizeof arr1[e1Elem2] == 1
+	#assert sizeof arr1[e1Elem3] == 1
+	#assert _:e1Elem1 == 0
+	#assert _:e1Elem2 == 3
+	#assert _:e1Elem3 == 4
+
+	enum e2 (+= 2)
+	{
+		e2Elem1[3],
+		e2Elem2,
+		e2Elem3
+	};
+	new arr2[e2];
+	#pragma unused arr2
+	#assert sizeof arr2[e2Elem1] == 3
+	#assert sizeof arr2[e2Elem2] == 2
+	#assert sizeof arr2[e2Elem3] == 2
+	#assert _:e2Elem1 == 0
+	#assert _:e2Elem2 == 3
+	#assert _:e2Elem3 == 5
+
+	enum e3 (*= 2)
+	{
+		e3Elem1 = 1,
+		e3Elem2[3],
+		e3Elem3
+	};
+	new arr3[e3];
+	#pragma unused arr3
+	#assert sizeof arr3[e3Elem1] == 1
+	#assert sizeof arr3[e3Elem2] == 3
+	#assert sizeof arr3[e3Elem3] == 1
+	#assert _:e3Elem1 == 1
+	#assert _:e3Elem2 == 2  // 1 * (1 * 2); the first "1" is the value of the previous
+	                        // enum item, the second "1" is the size of the previous
+	                        // item, and "2" is the increment (multiplier)
+	#assert _:e3Elem3 == 12 // 2 * (3 * 2)
+
+	enum e4 (<<= 2)
+	{
+		e4Elem1 = 1,
+		e4Elem2[3],
+		e4Elem3
+	};
+	new arr4[e4];
+	#pragma unused arr4
+	#assert sizeof arr4[e4Elem1] == 1
+	#assert sizeof arr4[e4Elem2] == 3
+	#assert sizeof arr4[e4Elem3] == 1
+	#assert _:e4Elem1 == 1
+	#assert _:e4Elem2 == 4  // 1 * (1 << 2) = 4
+	#assert _:e4Elem3 == 48 // 4 * (3 << 2) = 48
+
+	enum (<<= 0)
+	{
+		e5Elem1,
+		e5Elem2,
+		e5Elem3
+	};
+	#assert _:e5Elem1 == 0
+	#assert _:e5Elem2 == 0
+	#assert _:e5Elem3 == 0
+
+	enum (*= 1)
+	{
+		e5Elem1,
+		e5Elem2,
+		e5Elem3
+	};
+	#assert _:e5Elem1 == 0
+	#assert _:e5Elem2 == 0
+	#assert _:e5Elem3 == 0
+}

From f4a399fba7621b49b3290b6882820bb803784a1e Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Thu, 27 Feb 2020 02:55:07 +0700
Subject: [PATCH 02/10] Warn if the shift count is negative or too big

---
 source/compiler/sc1.c |  2 +-
 source/compiler/sc3.c | 21 +++++++++++++--------
 source/compiler/sc5.c |  3 ++-
 3 files changed, 16 insertions(+), 10 deletions(-)

diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index 21a2b56c..145161a3 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -6550,7 +6550,7 @@ static void SC_FASTCALL emit_param_index(emit_outval *p,int isrange,
       if (val==valid_values[i])
         return;
   } /* if */
-  error(50);    /* invalid range */
+  error(241);    /* negative or too big shift count */
 }
 
 static void SC_FASTCALL emit_param_nonneg(emit_outval *p)
diff --git a/source/compiler/sc3.c b/source/compiler/sc3.c
index 46486997..9eda02aa 100644
--- a/source/compiler/sc3.c
+++ b/source/compiler/sc3.c
@@ -626,15 +626,20 @@ static void plnge2(void (*oper)(void),
     if (check_userop(oper,lval1->tag,lval2->tag,2,NULL,&lval1->tag)) {
       lval1->ident=iEXPRESSION;
       lval1->constval=0;
-    } else if (lval1->ident==iCONSTEXPR && lval2->ident==iCONSTEXPR) {
-      /* only constant expression if both constant */
-      stgdel(index,cidx);       /* scratch generated code and calculate */
-      check_tagmismatch(lval1->tag,lval2->tag,FALSE,-1);
-      lval1->constval=calc(lval1->constval,oper,lval2->constval,&lval1->boolresult);
     } else {
-      check_tagmismatch(lval1->tag,lval2->tag,FALSE,-1);
-      (*oper)();                /* do the (signed) operation */
-      lval1->ident=iEXPRESSION;
+      if ((oper==ob_sal || oper==os_sar || oper==ou_sar)
+          && (lval2->ident==iCONSTEXPR && (lval2->constval<0 || lval2->constval>=PAWN_CELL_SIZE)))
+        error(241);             /* negative or too big shift count */
+      if (lval1->ident==iCONSTEXPR && lval2->ident==iCONSTEXPR) {
+        /* only constant expression if both constant */
+        stgdel(index,cidx);       /* scratch generated code and calculate */
+        check_tagmismatch(lval1->tag,lval2->tag,FALSE,-1);
+        lval1->constval=calc(lval1->constval,oper,lval2->constval,&lval1->boolresult);
+      } else {
+        check_tagmismatch(lval1->tag,lval2->tag,FALSE,-1);
+        (*oper)();                /* do the (signed) operation */
+        lval1->ident=iEXPRESSION;
+      } /* if */
     } /* if */
   } /* if */
 }
diff --git a/source/compiler/sc5.c b/source/compiler/sc5.c
index c5b31845..73733dd1 100644
--- a/source/compiler/sc5.c
+++ b/source/compiler/sc5.c
@@ -197,7 +197,8 @@ static char *warnmsg[] = {
 /*237*/  "user warning: %s\n",
 /*238*/  "meaningless combination of class specifiers (%s)\n",
 /*239*/  "literal array/string passed to a non-const parameter\n",
-/*240*/  "previously assigned value is never used (symbol \"%s\")\n"
+/*240*/  "previously assigned value is never used (symbol \"%s\")\n",
+/*241*/  "negative or too big shift count\n"
 };
 
 static char *noticemsg[] = {

From b384a759ed68c5f581ec8a792618e36cc28df864 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Wed, 17 Jun 2020 18:24:35 +0800
Subject: [PATCH 03/10] Add tests

---
 source/compiler/tests/warning_241.meta | 13 ++++++++++++
 source/compiler/tests/warning_241.pwn  | 29 ++++++++++++++++++++++++++
 2 files changed, 42 insertions(+)
 create mode 100644 source/compiler/tests/warning_241.meta
 create mode 100644 source/compiler/tests/warning_241.pwn

diff --git a/source/compiler/tests/warning_241.meta b/source/compiler/tests/warning_241.meta
new file mode 100644
index 00000000..9ef00cd0
--- /dev/null
+++ b/source/compiler/tests/warning_241.meta
@@ -0,0 +1,13 @@
+{
+  'test_type': 'output_check',
+  'errors': """
+warning_241.pwn(8) : warning 241: negative or too big shift count
+warning_241.pwn(9) : warning 241: negative or too big shift count
+warning_241.pwn(14) : warning 241: negative or too big shift count
+warning_241.pwn(15) : warning 241: negative or too big shift count
+warning_241.pwn(18) : warning 241: negative or too big shift count
+warning_241.pwn(19) : warning 241: negative or too big shift count
+warning_241.pwn(24) : warning 241: negative or too big shift count
+warning_241.pwn(25) : warning 241: negative or too big shift count
+"""
+}
diff --git a/source/compiler/tests/warning_241.pwn b/source/compiler/tests/warning_241.pwn
new file mode 100644
index 00000000..3f1afdd0
--- /dev/null
+++ b/source/compiler/tests/warning_241.pwn
@@ -0,0 +1,29 @@
+#include <console>
+
+main()
+{
+	new var = 1;
+
+	// Case 1: Both values are compile-time constants
+	printf("%d", 1 << -1); // warning 241
+	printf("%d", 1 << -2); // warning 241
+	printf("%d", 1 << 0);
+	printf("%d", 1 << 1);
+	printf("%d", 1 << 30);
+	printf("%d", 1 << 31);
+	printf("%d", 1 << 32); // warning 241
+	printf("%d", 1 << 33); // warning 241
+
+	// Case 2: Only the shift count is constant
+	printf("%d", var << -1); // warning 241
+	printf("%d", var << -2); // warning 241
+	printf("%d", var << 0);
+	printf("%d", var << 1);
+	printf("%d", var << 30);
+	printf("%d", var << 31);
+	printf("%d", var << 32); // warning 241
+	printf("%d", var << 33); // warning 241
+
+	printf("%d", 1 << var); // Just to make sure the warning works only
+	                        // if the shift count is a constant value
+}

From 5af4bbbd1c6cba058bf685306592b5e6562682d0 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Wed, 17 Jun 2020 18:32:41 +0800
Subject: [PATCH 04/10] Update one of the tests for `__emit`

Now `__emit` too uses warning 241 for `shl.c.pri/alt` and `shr.c.pri/alt`.
---
 source/compiler/tests/__emit_p5.meta | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/source/compiler/tests/__emit_p5.meta b/source/compiler/tests/__emit_p5.meta
index 6652ac2e..fb6118e5 100644
--- a/source/compiler/tests/__emit_p5.meta
+++ b/source/compiler/tests/__emit_p5.meta
@@ -1,29 +1,29 @@
 {
   'test_type': 'output_check',
   'errors': """
-__emit_p5.pwn(25) : error 050: invalid range
+__emit_p5.pwn(25) : warning 241: negative or too big shift count
 __emit_p5.pwn(26) : error 001: expected token: "-integer value-", but found "-data offset-"
 __emit_p5.pwn(27) : error 001: expected token: "-integer value-", but found "-function-"
 __emit_p5.pwn(28) : error 001: expected token: "-integer value-", but found "-reference-"
-__emit_p5.pwn(29) : error 050: invalid range
+__emit_p5.pwn(29) : warning 241: negative or too big shift count
 __emit_p5.pwn(30) : error 001: expected token: "-integer value-", but found "-local variable-"
 __emit_p5.pwn(31) : error 001: expected token: "-integer value-", but found "-data offset-"
 __emit_p5.pwn(32) : error 001: expected token: "-integer value-", but found "-label-"
-__emit_p5.pwn(33) : error 050: invalid range
-__emit_p5.pwn(34) : error 050: invalid range
-__emit_p5.pwn(35) : error 050: invalid range
-__emit_p5.pwn(36) : error 050: invalid range
-__emit_p5.pwn(37) : error 050: invalid range
-__emit_p5.pwn(38) : error 050: invalid range
+__emit_p5.pwn(33) : warning 241: negative or too big shift count
+__emit_p5.pwn(34) : warning 241: negative or too big shift count
+__emit_p5.pwn(35) : warning 241: negative or too big shift count
+__emit_p5.pwn(36) : warning 241: negative or too big shift count
+__emit_p5.pwn(37) : warning 241: negative or too big shift count
+__emit_p5.pwn(38) : warning 241: negative or too big shift count
 __emit_p5.pwn(61) : error 001: expected token: "-integer value-", but found "-data offset-"
 __emit_p5.pwn(62) : error 001: expected token: "-integer value-", but found "-function-"
 __emit_p5.pwn(63) : error 001: expected token: "-integer value-", but found "-reference-"
 __emit_p5.pwn(64) : error 001: expected token: "-integer value-", but found "-local variable-"
 __emit_p5.pwn(65) : error 001: expected token: "-integer value-", but found "-data offset-"
 __emit_p5.pwn(66) : error 001: expected token: "-integer value-", but found "-label-"
-__emit_p5.pwn(67) : error 050: invalid range
-__emit_p5.pwn(68) : error 050: invalid range
-__emit_p5.pwn(69) : error 050: invalid range
-__emit_p5.pwn(70) : error 050: invalid range
+__emit_p5.pwn(67) : warning 241: negative or too big shift count
+__emit_p5.pwn(68) : warning 241: negative or too big shift count
+__emit_p5.pwn(69) : warning 241: negative or too big shift count
+__emit_p5.pwn(70) : warning 241: negative or too big shift count
 """
 }

From 1f64f87ae165ba6eb7eaf91422fdac8129ec35a0 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Sun, 21 Jun 2020 23:02:10 +0800
Subject: [PATCH 05/10] Update the tests to cover right shift operations

---
 source/compiler/tests/warning_241.meta | 28 +++++++++++++++++-----
 source/compiler/tests/warning_241.pwn  | 32 ++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/source/compiler/tests/warning_241.meta b/source/compiler/tests/warning_241.meta
index 9ef00cd0..589d5d34 100644
--- a/source/compiler/tests/warning_241.meta
+++ b/source/compiler/tests/warning_241.meta
@@ -3,11 +3,27 @@
   'errors': """
 warning_241.pwn(8) : warning 241: negative or too big shift count
 warning_241.pwn(9) : warning 241: negative or too big shift count
-warning_241.pwn(14) : warning 241: negative or too big shift count
-warning_241.pwn(15) : warning 241: negative or too big shift count
-warning_241.pwn(18) : warning 241: negative or too big shift count
-warning_241.pwn(19) : warning 241: negative or too big shift count
-warning_241.pwn(24) : warning 241: negative or too big shift count
-warning_241.pwn(25) : warning 241: negative or too big shift count
+warning_241.pwn(10) : warning 241: negative or too big shift count
+warning_241.pwn(11) : warning 241: negative or too big shift count
+warning_241.pwn(12) : warning 241: negative or too big shift count
+warning_241.pwn(13) : warning 241: negative or too big shift count
+warning_241.pwn(26) : warning 241: negative or too big shift count
+warning_241.pwn(27) : warning 241: negative or too big shift count
+warning_241.pwn(28) : warning 241: negative or too big shift count
+warning_241.pwn(29) : warning 241: negative or too big shift count
+warning_241.pwn(30) : warning 241: negative or too big shift count
+warning_241.pwn(31) : warning 241: negative or too big shift count
+warning_241.pwn(34) : warning 241: negative or too big shift count
+warning_241.pwn(35) : warning 241: negative or too big shift count
+warning_241.pwn(36) : warning 241: negative or too big shift count
+warning_241.pwn(37) : warning 241: negative or too big shift count
+warning_241.pwn(38) : warning 241: negative or too big shift count
+warning_241.pwn(39) : warning 241: negative or too big shift count
+warning_241.pwn(52) : warning 241: negative or too big shift count
+warning_241.pwn(53) : warning 241: negative or too big shift count
+warning_241.pwn(54) : warning 241: negative or too big shift count
+warning_241.pwn(55) : warning 241: negative or too big shift count
+warning_241.pwn(56) : warning 241: negative or too big shift count
+warning_241.pwn(57) : warning 241: negative or too big shift count
 """
 }
diff --git a/source/compiler/tests/warning_241.pwn b/source/compiler/tests/warning_241.pwn
index 3f1afdd0..17bbe726 100644
--- a/source/compiler/tests/warning_241.pwn
+++ b/source/compiler/tests/warning_241.pwn
@@ -7,22 +7,54 @@ main()
 	// Case 1: Both values are compile-time constants
 	printf("%d", 1 << -1); // warning 241
 	printf("%d", 1 << -2); // warning 241
+	printf("%d", 1 >> -1); // warning 241
+	printf("%d", 1 >> -2); // warning 241
+	printf("%d", 1 >>> -1); // warning 241
+	printf("%d", 1 >>> -2); // warning 241
 	printf("%d", 1 << 0);
 	printf("%d", 1 << 1);
+	printf("%d", 1 >> 0);
+	printf("%d", 1 >> 1);
+	printf("%d", 1 >>> 0);
+	printf("%d", 1 >>> 1);
 	printf("%d", 1 << 30);
 	printf("%d", 1 << 31);
+	printf("%d", 1 >> 30);
+	printf("%d", 1 >> 31);
+	printf("%d", 1 >>> 30);
+	printf("%d", 1 >>> 31);
 	printf("%d", 1 << 32); // warning 241
 	printf("%d", 1 << 33); // warning 241
+	printf("%d", 1 >> 32); // warning 241
+	printf("%d", 1 >> 33); // warning 241
+	printf("%d", 1 >>> 32); // warning 241
+	printf("%d", 1 >>> 33); // warning 241
 
 	// Case 2: Only the shift count is constant
 	printf("%d", var << -1); // warning 241
 	printf("%d", var << -2); // warning 241
+	printf("%d", var >> -1); // warning 241
+	printf("%d", var >> -2); // warning 241
+	printf("%d", var >>> -1); // warning 241
+	printf("%d", var >>> -2); // warning 241
 	printf("%d", var << 0);
 	printf("%d", var << 1);
+	printf("%d", var >> 0);
+	printf("%d", var >> 1);
+	printf("%d", var >>> 0);
+	printf("%d", var >>> 1);
 	printf("%d", var << 30);
 	printf("%d", var << 31);
+	printf("%d", var >> 30);
+	printf("%d", var >> 31);
+	printf("%d", var >>> 30);
+	printf("%d", var >>> 31);
 	printf("%d", var << 32); // warning 241
 	printf("%d", var << 33); // warning 241
+	printf("%d", var >> 32); // warning 241
+	printf("%d", var >> 33); // warning 241
+	printf("%d", var >>> 32); // warning 241
+	printf("%d", var >>> 33); // warning 241
 
 	printf("%d", 1 << var); // Just to make sure the warning works only
 	                        // if the shift count is a constant value

From 681fbdb97da2d824d874ff1c0be821fcef8b2c8f Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Fri, 26 Jun 2020 18:11:03 +0800
Subject: [PATCH 06/10] Warn on invalid shift count for enum increment

---
 source/compiler/sc1.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index 145161a3..a23eccb5 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -2967,8 +2967,12 @@ static void decl_enum(int vclass,int fstatic)
     if (tok==taADD || tok==taMULT || tok==taSHL) {
       inctok=tok;
       constexpr(&increment,NULL,NULL);
-      if (tok==taSHL && increment<0)
-        increment=0;
+      if (tok==taSHL) {
+        if (increment<0 || increment>=PAWN_CELL_SIZE)
+          error(241);                   /* negative or too big shift count */
+        if (increment<0)
+          increment=0;
+      } /* if */
     } else {
       lexpush();
     } /* if */

From 9bbd7b458c0490d65c92538a3b519ec564febcba Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Tue, 30 Jun 2020 00:01:17 +0800
Subject: [PATCH 07/10] Warn about shift overflow in enum item declarations

---
 source/compiler/sc1.c | 21 +++++++++++++++++----
 source/compiler/sc5.c |  3 ++-
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index a23eccb5..864c6e5a 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -2929,6 +2929,7 @@ static void decl_enum(int vclass,int fstatic)
   char *str;
   int tag,explicittag;
   int inctok;
+  int overflow;
   cell increment;
   constvalue_root *enumroot=NULL;
   symbol *enumsym=NULL;
@@ -2996,13 +2997,16 @@ static void decl_enum(int vclass,int fstatic)
   needtoken('{');
   /* go through all constants */
   value=0;                              /* default starting value */
+  overflow=FALSE;
   do {
     int idxtag,fieldtag;
+    int symline;
     symbol *sym;
     if (matchtoken('}')) {              /* quick exit if '}' follows ',' */
       lexpush();
       break;
     } /* if */
+    symline=fline;
     idxtag=(enumname[0]=='\0') ? tag : pc_addtag(NULL); /* optional explicit item tag */
     if (needtoken(tSYMBOL)) {           /* read in (new) token */
       tokeninfo(&val,&str);             /* get the information */
@@ -3016,8 +3020,14 @@ static void decl_enum(int vclass,int fstatic)
       constexpr(&size,&fieldtag,NULL);  /* get size */
       needtoken(']');
     } /* if */
-    if (matchtoken('='))
+    if (matchtoken('=')) {
       constexpr(&value,NULL,NULL);      /* get value */
+      overflow=FALSE;
+    } else if (overflow) {
+      errorset(sSETPOS,symline);
+      error(242,constname);             /* shift overflow for enum item */
+      errorset(sSETPOS,-1);
+    } /* if */
     /* add_constant() checks whether a variable (global or local) or
      * a constant with the same name already exists
      */
@@ -3043,12 +3053,15 @@ static void decl_enum(int vclass,int fstatic)
       sym->usage |= uENUMFIELD;
       append_constval(enumroot,constname,value,tag);
     } /* if */
-    if (inctok==taADD)
+    if (inctok==taADD) {
       value+=size;
-    else if (inctok==taMULT)
+    } else if (inctok==taMULT) {
       value*=(size*increment);
-    else // taSHL
+    } else { // taSHL
+      if ((ucell)value>=((ucell)1 << (PAWN_CELL_SIZE-increment)))
+        overflow=TRUE;
       value*=(size << increment);
+    } /* if */
   } while (matchtoken(','));
   needtoken('}');       /* terminates the constant list */
   matchtoken(';');      /* eat an optional ; */
diff --git a/source/compiler/sc5.c b/source/compiler/sc5.c
index 73733dd1..7aa845ad 100644
--- a/source/compiler/sc5.c
+++ b/source/compiler/sc5.c
@@ -198,7 +198,8 @@ static char *warnmsg[] = {
 /*238*/  "meaningless combination of class specifiers (%s)\n",
 /*239*/  "literal array/string passed to a non-const parameter\n",
 /*240*/  "previously assigned value is never used (symbol \"%s\")\n",
-/*241*/  "negative or too big shift count\n"
+/*241*/  "negative or too big shift count\n",
+/*242*/  "shift overflow in enum item declaration (symbol \"%s\")\n"
 };
 
 static char *noticemsg[] = {

From 093097724d1f18959355df21862a218a47dd7789 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Tue, 30 Jun 2020 00:17:28 +0800
Subject: [PATCH 08/10] Update tests

---
 source/compiler/tests/warning_241.meta        | 29 ------
 source/compiler/tests/warning_241_242.meta    | 33 +++++++
 .../{warning_241.pwn => warning_241_242.pwn}  | 95 +++++++++++++++++++
 3 files changed, 128 insertions(+), 29 deletions(-)
 delete mode 100644 source/compiler/tests/warning_241.meta
 create mode 100644 source/compiler/tests/warning_241_242.meta
 rename source/compiler/tests/{warning_241.pwn => warning_241_242.pwn} (70%)

diff --git a/source/compiler/tests/warning_241.meta b/source/compiler/tests/warning_241.meta
deleted file mode 100644
index 589d5d34..00000000
--- a/source/compiler/tests/warning_241.meta
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  'test_type': 'output_check',
-  'errors': """
-warning_241.pwn(8) : warning 241: negative or too big shift count
-warning_241.pwn(9) : warning 241: negative or too big shift count
-warning_241.pwn(10) : warning 241: negative or too big shift count
-warning_241.pwn(11) : warning 241: negative or too big shift count
-warning_241.pwn(12) : warning 241: negative or too big shift count
-warning_241.pwn(13) : warning 241: negative or too big shift count
-warning_241.pwn(26) : warning 241: negative or too big shift count
-warning_241.pwn(27) : warning 241: negative or too big shift count
-warning_241.pwn(28) : warning 241: negative or too big shift count
-warning_241.pwn(29) : warning 241: negative or too big shift count
-warning_241.pwn(30) : warning 241: negative or too big shift count
-warning_241.pwn(31) : warning 241: negative or too big shift count
-warning_241.pwn(34) : warning 241: negative or too big shift count
-warning_241.pwn(35) : warning 241: negative or too big shift count
-warning_241.pwn(36) : warning 241: negative or too big shift count
-warning_241.pwn(37) : warning 241: negative or too big shift count
-warning_241.pwn(38) : warning 241: negative or too big shift count
-warning_241.pwn(39) : warning 241: negative or too big shift count
-warning_241.pwn(52) : warning 241: negative or too big shift count
-warning_241.pwn(53) : warning 241: negative or too big shift count
-warning_241.pwn(54) : warning 241: negative or too big shift count
-warning_241.pwn(55) : warning 241: negative or too big shift count
-warning_241.pwn(56) : warning 241: negative or too big shift count
-warning_241.pwn(57) : warning 241: negative or too big shift count
-"""
-}
diff --git a/source/compiler/tests/warning_241_242.meta b/source/compiler/tests/warning_241_242.meta
new file mode 100644
index 00000000..82f310bb
--- /dev/null
+++ b/source/compiler/tests/warning_241_242.meta
@@ -0,0 +1,33 @@
+{
+  'test_type': 'output_check',
+  'errors': """
+warning_241_242.pwn(3) : warning 241: negative or too big shift count
+warning_241_242.pwn(8) : warning 241: negative or too big shift count
+warning_241_242.pwn(56) : warning 242: shift overflow in enum item declaration (symbol "e32")
+warning_241_242.pwn(95) : warning 242: shift overflow in enum item declaration (symbol "f34")
+warning_241_242.pwn(103) : warning 241: negative or too big shift count
+warning_241_242.pwn(104) : warning 241: negative or too big shift count
+warning_241_242.pwn(105) : warning 241: negative or too big shift count
+warning_241_242.pwn(106) : warning 241: negative or too big shift count
+warning_241_242.pwn(107) : warning 241: negative or too big shift count
+warning_241_242.pwn(108) : warning 241: negative or too big shift count
+warning_241_242.pwn(121) : warning 241: negative or too big shift count
+warning_241_242.pwn(122) : warning 241: negative or too big shift count
+warning_241_242.pwn(123) : warning 241: negative or too big shift count
+warning_241_242.pwn(124) : warning 241: negative or too big shift count
+warning_241_242.pwn(125) : warning 241: negative or too big shift count
+warning_241_242.pwn(126) : warning 241: negative or too big shift count
+warning_241_242.pwn(129) : warning 241: negative or too big shift count
+warning_241_242.pwn(130) : warning 241: negative or too big shift count
+warning_241_242.pwn(131) : warning 241: negative or too big shift count
+warning_241_242.pwn(132) : warning 241: negative or too big shift count
+warning_241_242.pwn(133) : warning 241: negative or too big shift count
+warning_241_242.pwn(134) : warning 241: negative or too big shift count
+warning_241_242.pwn(147) : warning 241: negative or too big shift count
+warning_241_242.pwn(148) : warning 241: negative or too big shift count
+warning_241_242.pwn(149) : warning 241: negative or too big shift count
+warning_241_242.pwn(150) : warning 241: negative or too big shift count
+warning_241_242.pwn(151) : warning 241: negative or too big shift count
+warning_241_242.pwn(152) : warning 241: negative or too big shift count
+"""
+}
diff --git a/source/compiler/tests/warning_241.pwn b/source/compiler/tests/warning_241_242.pwn
similarity index 70%
rename from source/compiler/tests/warning_241.pwn
rename to source/compiler/tests/warning_241_242.pwn
index 17bbe726..1cd6d04c 100644
--- a/source/compiler/tests/warning_241.pwn
+++ b/source/compiler/tests/warning_241_242.pwn
@@ -1,5 +1,100 @@
 #include <console>
 
+enum (<<= 32)
+{
+	a0 = 0
+};
+
+enum (<<= -1)
+{
+	b0 = 0
+};
+
+enum (<<= 1)
+{
+	c0 = 0
+};
+enum (<<= 31)
+{
+	d0 = 0
+};
+
+enum (<<= 1)
+{
+	e0 = 1,
+	e1,
+	e2,
+	e3,
+	e4,
+	e5,
+	e6,
+	e7,
+	e8,
+	e9,
+	e10,
+	e11,
+	e12,
+	e13,
+	e14,
+	e15,
+	e16,
+	e17,
+	e18,
+	e19,
+	e20,
+	e21,
+	e22,
+	e23,
+	e24,
+	e25,
+	e26,
+	e27,
+	e28,
+	e29,
+	e30,
+	e31,        // 0b10000000000000000000000000000000
+	e32         // overflow
+};
+
+enum (<<= 1)
+{
+	f0 = 1,
+	f1,
+	f2,
+	f3,
+	f4,
+	f5,
+	f6,
+	f7,
+	f8,
+	f9,
+	f10,
+	f11,
+	f12,
+	f13,
+	f14,
+	f15,
+	f16,
+	f17,
+	f18,
+	f19,
+	f20,
+	f21,
+	f22,
+	f23,
+	f24,
+	f25,
+	f26,
+	f27,
+	f28,
+	f29,
+	f30,
+	f31,        // 0b10000000000000000000000000000000
+	f32 = f31-1,// 0b01111111111111111111111111111111
+	f33,        // 0b11111111111111111111111111111110
+	f34         // overflow
+};
+
 main()
 {
 	new var = 1;

From 3d0ca3208e8d78431c0876c9a6b51011694f9b46 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Wed, 16 Sep 2020 19:21:12 +0800
Subject: [PATCH 09/10] Reset variable "overflow" when the warning has been
 shown, so it won't be shown again for the next enum item. Also rename the
 variable into more descriptive "warn_overflow".

---
 source/compiler/sc1.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/source/compiler/sc1.c b/source/compiler/sc1.c
index 864c6e5a..ff711bad 100644
--- a/source/compiler/sc1.c
+++ b/source/compiler/sc1.c
@@ -2929,7 +2929,7 @@ static void decl_enum(int vclass,int fstatic)
   char *str;
   int tag,explicittag;
   int inctok;
-  int overflow;
+  int warn_overflow;
   cell increment;
   constvalue_root *enumroot=NULL;
   symbol *enumsym=NULL;
@@ -2997,7 +2997,7 @@ static void decl_enum(int vclass,int fstatic)
   needtoken('{');
   /* go through all constants */
   value=0;                              /* default starting value */
-  overflow=FALSE;
+  warn_overflow=FALSE;
   do {
     int idxtag,fieldtag;
     int symline;
@@ -3022,11 +3022,12 @@ static void decl_enum(int vclass,int fstatic)
     } /* if */
     if (matchtoken('=')) {
       constexpr(&value,NULL,NULL);      /* get value */
-      overflow=FALSE;
-    } else if (overflow) {
+      warn_overflow=FALSE;
+    } else if (warn_overflow) {
       errorset(sSETPOS,symline);
       error(242,constname);             /* shift overflow for enum item */
       errorset(sSETPOS,-1);
+      warn_overflow=FALSE;
     } /* if */
     /* add_constant() checks whether a variable (global or local) or
      * a constant with the same name already exists
@@ -3059,7 +3060,7 @@ static void decl_enum(int vclass,int fstatic)
       value*=(size*increment);
     } else { // taSHL
       if ((ucell)value>=((ucell)1 << (PAWN_CELL_SIZE-increment)))
-        overflow=TRUE;
+        warn_overflow=TRUE;
       value*=(size << increment);
     } /* if */
   } while (matchtoken(','));

From e7451046b0c34cbe0ccb6f50251cfbfccacee254 Mon Sep 17 00:00:00 2001
From: Stanislav Gromov <gromovstanislav@yandex.ru>
Date: Wed, 16 Sep 2020 20:23:18 +0800
Subject: [PATCH 10/10] Update tests

---
 source/compiler/tests/warning_241_242.meta | 19 ++++++++++---------
 source/compiler/tests/warning_241_242.pwn  |  8 +++++---
 2 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/source/compiler/tests/warning_241_242.meta b/source/compiler/tests/warning_241_242.meta
index 82f310bb..b9aba086 100644
--- a/source/compiler/tests/warning_241_242.meta
+++ b/source/compiler/tests/warning_241_242.meta
@@ -4,30 +4,31 @@
 warning_241_242.pwn(3) : warning 241: negative or too big shift count
 warning_241_242.pwn(8) : warning 241: negative or too big shift count
 warning_241_242.pwn(56) : warning 242: shift overflow in enum item declaration (symbol "e32")
-warning_241_242.pwn(95) : warning 242: shift overflow in enum item declaration (symbol "f34")
-warning_241_242.pwn(103) : warning 241: negative or too big shift count
-warning_241_242.pwn(104) : warning 241: negative or too big shift count
+warning_241_242.pwn(96) : warning 242: shift overflow in enum item declaration (symbol "f34")
+warning_241_242.pwn(97) : warning 242: shift overflow in enum item declaration (symbol "f35")
 warning_241_242.pwn(105) : warning 241: negative or too big shift count
 warning_241_242.pwn(106) : warning 241: negative or too big shift count
 warning_241_242.pwn(107) : warning 241: negative or too big shift count
 warning_241_242.pwn(108) : warning 241: negative or too big shift count
-warning_241_242.pwn(121) : warning 241: negative or too big shift count
-warning_241_242.pwn(122) : warning 241: negative or too big shift count
+warning_241_242.pwn(109) : warning 241: negative or too big shift count
+warning_241_242.pwn(110) : warning 241: negative or too big shift count
 warning_241_242.pwn(123) : warning 241: negative or too big shift count
 warning_241_242.pwn(124) : warning 241: negative or too big shift count
 warning_241_242.pwn(125) : warning 241: negative or too big shift count
 warning_241_242.pwn(126) : warning 241: negative or too big shift count
-warning_241_242.pwn(129) : warning 241: negative or too big shift count
-warning_241_242.pwn(130) : warning 241: negative or too big shift count
+warning_241_242.pwn(127) : warning 241: negative or too big shift count
+warning_241_242.pwn(128) : warning 241: negative or too big shift count
 warning_241_242.pwn(131) : warning 241: negative or too big shift count
 warning_241_242.pwn(132) : warning 241: negative or too big shift count
 warning_241_242.pwn(133) : warning 241: negative or too big shift count
 warning_241_242.pwn(134) : warning 241: negative or too big shift count
-warning_241_242.pwn(147) : warning 241: negative or too big shift count
-warning_241_242.pwn(148) : warning 241: negative or too big shift count
+warning_241_242.pwn(135) : warning 241: negative or too big shift count
+warning_241_242.pwn(136) : warning 241: negative or too big shift count
 warning_241_242.pwn(149) : warning 241: negative or too big shift count
 warning_241_242.pwn(150) : warning 241: negative or too big shift count
 warning_241_242.pwn(151) : warning 241: negative or too big shift count
 warning_241_242.pwn(152) : warning 241: negative or too big shift count
+warning_241_242.pwn(153) : warning 241: negative or too big shift count
+warning_241_242.pwn(154) : warning 241: negative or too big shift count
 """
 }
diff --git a/source/compiler/tests/warning_241_242.pwn b/source/compiler/tests/warning_241_242.pwn
index 1cd6d04c..74daa095 100644
--- a/source/compiler/tests/warning_241_242.pwn
+++ b/source/compiler/tests/warning_241_242.pwn
@@ -51,9 +51,10 @@ enum (<<= 1)
 	e27,
 	e28,
 	e29,
-	e30,
+	e30,        // 0b01000000000000000000000000000000
 	e31,        // 0b10000000000000000000000000000000
-	e32         // overflow
+	e32,        // 0b00000000000000000000000000000000 (overflow)
+	e33         // 0b00000000000000000000000000000000
 };
 
 enum (<<= 1)
@@ -92,7 +93,8 @@ enum (<<= 1)
 	f31,        // 0b10000000000000000000000000000000
 	f32 = f31-1,// 0b01111111111111111111111111111111
 	f33,        // 0b11111111111111111111111111111110
-	f34         // overflow
+	f34,        // 0b11111111111111111111111111111100 (overflow)
+	f35         // 0b11111111111111111111111111111000 (overflow)
 };
 
 main()