diff --git a/Source/GSString.m b/Source/GSString.m
index 320d31604..41630449e 100644
--- a/Source/GSString.m
+++ b/Source/GSString.m
@@ -2536,11 +2536,6 @@ rangeOfString_c(GSStr self, NSString *aString, unsigned mask, NSRange aRange)
 {
   Class	c;
 
-  if (aString == nil)
-    [NSException raise: NSInvalidArgumentException format: @"range of nil"];
-  if (GSObjCIsInstance(aString) == NO)
-    return strRangeCsNs((id)self, aString, mask, aRange);
-
   c = GSObjCClass(aString);
   if (GSObjCIsKindOf(c, GSUnicodeStringClass) == YES
     || (c == GSMutableStringClass && ((GSStr)aString)->_flags.wide == 1))
@@ -2558,11 +2553,6 @@ rangeOfString_u(GSStr self, NSString *aString, unsigned mask, NSRange aRange)
 {
   Class	c;
 
-  if (aString == nil)
-    [NSException raise: NSInvalidArgumentException format: @"range of nil"];
-  if (GSObjCIsInstance(aString) == NO)
-    return strRangeUsNs((id)self, aString, mask, aRange);
-
   c = GSObjCClass(aString);
   if (GSObjCIsKindOf(c, GSUnicodeStringClass) == YES
     || (c == GSMutableStringClass && ((GSStr)aString)->_flags.wide == 1))
@@ -3016,6 +3006,15 @@ transmute(GSStr self, NSString *aString)
 		  options: (unsigned)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, _count);
+  if (aString == nil)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] nil string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+  if (GSObjCIsInstance(aString) == NO)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] not a string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
   return rangeOfString_c((GSStr)self, aString, mask, aRange);
 }
 
@@ -3329,6 +3328,15 @@ agree, create a new GSCInlineString otherwise.
 		  options: (unsigned)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, _count);
+  if (aString == nil)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] nil string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+  if (GSObjCIsInstance(aString) == NO)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] not a string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
   return rangeOfString_u((GSStr)self, aString, mask, aRange);
 }
 
@@ -4127,6 +4135,15 @@ NSAssert(_flags.free == 1 && _zone != 0, NSInternalInconsistencyException);
 		  options: (unsigned)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, _count);
+  if (aString == nil)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] nil string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+  if (GSObjCIsInstance(aString) == NO)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] not a string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
   if (_flags.wide == 1)
     return rangeOfString_u((GSStr)self, aString, mask, aRange);
   else
@@ -4590,6 +4607,7 @@ NSAssert(_flags.free == 1 && _zone != 0, NSInternalInconsistencyException);
 			    options: (unsigned)mask
 			      range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, ((GSStr)_parent)->_count);
   return [_parent rangeOfCharacterFromSet: aSet options: mask range: aRange];
 }
 
@@ -4597,6 +4615,15 @@ NSAssert(_flags.free == 1 && _zone != 0, NSInternalInconsistencyException);
 		  options: (unsigned)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, ((GSStr)_parent)->_count);
+  if (aString == nil)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] nil string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+  if (GSObjCIsInstance(aString) == NO)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] not a string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
   return [_parent rangeOfString: aString options: mask range: aRange];
 }
 
@@ -4788,6 +4815,15 @@ NSAssert(_flags.free == 1 && _zone != 0, NSInternalInconsistencyException);
 		  options: (unsigned)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, ((GSStr)_parent)->_count);
+  if (aString == nil)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] nil string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
+  if (GSObjCIsInstance(aString) == NO)
+    [NSException raise: NSInvalidArgumentException
+		format: @"[%@ -%@] not a string argument",
+      NSStringFromClass([self class]), NSStringFromSelector(_cmd)];
   if (((GSStr)_parent)->_flags.wide == 1)
     return rangeOfString_u((GSStr)_parent, aString, mask, aRange);
   else
diff --git a/Source/GSeq.h b/Source/GSeq.h
index fc9236107..848203e07 100644
--- a/Source/GSeq.h
+++ b/Source/GSeq.h
@@ -381,10 +381,13 @@ GSEQ_STRCOMP(NSString *ss, NSString *os, unsigned mask, NSRange aRange)
   unsigned	oLength;			/* Length of other.	*/
   unsigned	sLength = GSEQ_SLEN;
 
+#if	0
+  /* Range should be checked in calling code */
   if (aRange.location > sLength)
     [NSException raise: NSRangeException format: @"Invalid location."];
   if (aRange.length > (sLength - aRange.location))
     [NSException raise: NSRangeException format: @"Invalid location+length."];
+#endif
 
   oLength = GSEQ_OLEN;
   if (aRange.length == 0)
@@ -604,11 +607,14 @@ GSEQ_STRRANGE(NSString *ss, NSString *os, unsigned mask, NSRange aRange)
   
   /* Check that the search range is reasonable */
   myLength = GSEQ_SLEN;
+
+#if	0
+  /* Range should be checked in calling code */
   if (aRange.location > myLength)
     [NSException raise: NSRangeException format: @"Invalid location."];
   if (aRange.length > (myLength - aRange.location))
     [NSException raise: NSRangeException format: @"Invalid location+length."];
-
+#endif
 
   /* Ensure the string can be found */
   strLength = GSEQ_OLEN;
diff --git a/Source/NSString.m b/Source/NSString.m
index 41dffd0e9..aa04d99a5 100644
--- a/Source/NSString.m
+++ b/Source/NSString.m
@@ -1809,6 +1809,7 @@ handle_printf_atsign (FILE *stream,
 		  options: (unsigned int)mask
 		    range: (NSRange)aRange
 {
+  GS_RANGE_CHECK(aRange, [self length]);
   if (aString == nil)
     [NSException raise: NSInvalidArgumentException format: @"range of nil"];
   return strRangeNsNs(self, aString, mask, aRange);