diff --git a/dlls/ntdll/debugbuffer.c b/dlls/ntdll/debugbuffer.c
index be1ddffc1da..0ad8882c267 100644
--- a/dlls/ntdll/debugbuffer.c
+++ b/dlls/ntdll/debugbuffer.c
@@ -96,7 +96,7 @@ PDEBUG_BUFFER WINAPI RtlCreateQueryDebugBuffer(IN ULONG iSize, IN BOOLEAN iEvent
    if (iSize < sizeof(DEBUG_BUFFER)) {
      iSize = sizeof(DEBUG_BUFFER);
    }
-   oBuf = (PDEBUG_BUFFER) RtlAllocateHeap(GetProcessHeap(), 0, iSize);
+   oBuf = RtlAllocateHeap(GetProcessHeap(), 0, iSize);
    memset(oBuf, 0, iSize);
    FIXME("(%d, %d): returning %p\n", iSize, iEventPair, oBuf);
    return oBuf;
diff --git a/dlls/ntdll/reg.c b/dlls/ntdll/reg.c
index af0f20015b0..8aba3aea9cc 100644
--- a/dlls/ntdll/reg.c
+++ b/dlls/ntdll/reg.c
@@ -325,7 +325,7 @@ NTSTATUS WINAPI RtlpNtEnumerateSubKey( HANDLE handle, UNICODE_STRING *out, ULONG
   if (out->Length)
   {
     dwLen = out->Length + sizeof(KEY_BASIC_INFORMATION);
-    info = (KEY_BASIC_INFORMATION*)RtlAllocateHeap( GetProcessHeap(), 0, dwLen );
+    info = RtlAllocateHeap( GetProcessHeap(), 0, dwLen );
     if (!info)
       return STATUS_NO_MEMORY;
   }
@@ -543,7 +543,7 @@ NTSTATUS WINAPI RtlpNtQueryValueKey( HANDLE handle, ULONG *result_type, PBYTE de
     DWORD dwResultLen;
     DWORD dwLen = sizeof (KEY_VALUE_PARTIAL_INFORMATION) + (result_len ? *result_len : 0);
 
-    info = (KEY_VALUE_PARTIAL_INFORMATION*)RtlAllocateHeap( GetProcessHeap(), 0, dwLen );
+    info = RtlAllocateHeap( GetProcessHeap(), 0, dwLen );
     if (!info)
       return STATUS_NO_MEMORY;
 
@@ -1220,8 +1220,7 @@ NTSTATUS WINAPI RtlQueryRegistryValues(IN ULONG RelativeTo, IN PCWSTR Path,
                 {
                     buflen = len;
                     RtlFreeHeap(GetProcessHeap(), 0, pInfo);
-                    pInfo = (KEY_VALUE_FULL_INFORMATION*)RtlAllocateHeap(
-                        GetProcessHeap(), 0, buflen);
+                    pInfo = RtlAllocateHeap(GetProcessHeap(), 0, buflen);
                     NtEnumerateValueKey(handle, i, KeyValueFullInformation,
                         pInfo, buflen, &len);
                 }
@@ -1255,8 +1254,7 @@ NTSTATUS WINAPI RtlQueryRegistryValues(IN ULONG RelativeTo, IN PCWSTR Path,
             {
                 buflen = len;
                 RtlFreeHeap(GetProcessHeap(), 0, pInfo);
-                pInfo = (KEY_VALUE_FULL_INFORMATION*)RtlAllocateHeap(
-                    GetProcessHeap(), 0, buflen);
+                pInfo = RtlAllocateHeap(GetProcessHeap(), 0, buflen);
                 status = NtQueryValueKey(handle, &Value,
                     KeyValueFullInformation, pInfo, buflen, &len);
             }
diff --git a/dlls/ntdll/rtlstr.c b/dlls/ntdll/rtlstr.c
index 3a50155d8f2..de208a236f0 100644
--- a/dlls/ntdll/rtlstr.c
+++ b/dlls/ntdll/rtlstr.c
@@ -2126,7 +2126,7 @@ NTSTATUS WINAPI RtlStringFromGUID(const GUID* guid, UNICODE_STRING *str)
 
   str->Length = GUID_STRING_LENGTH * sizeof(WCHAR);
   str->MaximumLength = str->Length + sizeof(WCHAR);
-  str->Buffer = (WCHAR*)RtlAllocateHeap(GetProcessHeap(), 0, str->MaximumLength);
+  str->Buffer = RtlAllocateHeap(GetProcessHeap(), 0, str->MaximumLength);
   if (!str->Buffer)
   {
     str->Length = str->MaximumLength = 0;
diff --git a/dlls/ntdll/signal_i386.c b/dlls/ntdll/signal_i386.c
index fb2c0fdd160..a9482e97b68 100644
--- a/dlls/ntdll/signal_i386.c
+++ b/dlls/ntdll/signal_i386.c
@@ -599,7 +599,7 @@ static void wine_sigacthandler( int signal, siginfo_t *siginfo, void *sigcontext
 
     __asm__ __volatile__("mov %ss,%ax; mov %ax,%ds; mov %ax,%es");
 
-    thread_data = (struct ntdll_thread_data *)get_current_teb()->SystemReserved2;
+    thread_data = get_current_teb()->SystemReserved2;
     wine_set_fs( thread_data->fs );
     wine_set_gs( thread_data->gs );