diff --git a/rtl/objpas/sysutils/sysstr.inc b/rtl/objpas/sysutils/sysstr.inc
index e78db4e48a..fa79d683ff 100644
--- a/rtl/objpas/sysutils/sysstr.inc
+++ b/rtl/objpas/sysutils/sysstr.inc
@@ -538,7 +538,7 @@ begin
   AnsiSameStr:=AnsiCompareStr(S1,S2)=0;
 end;
 
-function AnsiLastChar(const S: string): PAnsiChar;
+function AnsiLastChar(const S: AnsiString): PAnsiChar;
 
 begin
   //!! No multibyte yet, so we return the last one.
diff --git a/rtl/objpas/sysutils/sysstrh.inc b/rtl/objpas/sysutils/sysstrh.inc
index aecb19e90c..be6dc60d5c 100644
--- a/rtl/objpas/sysutils/sysstrh.inc
+++ b/rtl/objpas/sysutils/sysstrh.inc
@@ -100,7 +100,7 @@ function AnsiStrLComp(S1, S2: PAnsiChar; MaxLen: SizeUInt): Integer;{$ifdef SYSU
 function AnsiStrLIComp(S1, S2: PAnsiChar; MaxLen: SizeUInt): Integer;{$ifdef SYSUTILSINLINE}inline;{$endif}
 function AnsiStrLower(Str: PAnsiChar): PAnsiChar;{$ifdef SYSUTILSINLINE}inline;{$endif}
 function AnsiStrUpper(Str: PAnsiChar): PAnsiChar;{$ifdef SYSUTILSINLINE}inline;{$endif}
-function AnsiLastChar(const S: string): PAnsiChar;
+function AnsiLastChar(const S: AnsiString): PAnsiChar;
 function AnsiStrLastChar(Str: PAnsiChar): PAnsiChar;
 
 function Trim(const S: ansistring): ansistring;