gh-124064: Fix -Wconversion warnings in pycore_{gc,list,stackref}.h (#124174)

Author: vstinner

Include/internal/pycore_gc.h

@@ -227,7 +227,7 @@ static inline void _PyGC_CLEAR_FINALIZED(PyObject *op) {
     _PyObject_CLEAR_GC_BITS(op, _PyGC_BITS_FINALIZED);
 #else
     PyGC_Head *gc = _Py_AS_GC(op);
-    gc->_gc_prev &= ~_PyGC_PREV_MASK_FINALIZED;
+    gc->_gc_prev &= ~(uintptr_t)_PyGC_PREV_MASK_FINALIZED;
 #endif
 }
 

Include/internal/pycore_list.h

@@ -45,7 +45,7 @@ _Py_memory_repeat(char* dest, Py_ssize_t len_dest, Py_ssize_t len_src)
     Py_ssize_t copied = len_src;
     while (copied < len_dest) {
         Py_ssize_t bytes_to_copy = Py_MIN(copied, len_dest - copied);
-        memcpy(dest + copied, dest, bytes_to_copy);
+        memcpy(dest + copied, dest, (size_t)bytes_to_copy);
         copied += bytes_to_copy;
     }
 }

Include/internal/pycore_stackref.h

@@ -98,7 +98,7 @@ typedef union _PyStackRef {
 static inline PyObject *
 PyStackRef_AsPyObjectBorrow(_PyStackRef stackref)
 {
-    PyObject *cleared = ((PyObject *)((stackref).bits & (~Py_TAG_BITS)));
+    PyObject *cleared = ((PyObject *)((stackref).bits & (~(uintptr_t)Py_TAG_BITS)));
     return cleared;
 }
 #else
@@ -133,7 +133,7 @@ _PyStackRef_FromPyObjectSteal(PyObject *obj)
 {
     // Make sure we don't take an already tagged value.
     assert(((uintptr_t)obj & Py_TAG_BITS) == 0);
-    int tag = (obj == NULL || _Py_IsImmortal(obj)) ? (Py_TAG_DEFERRED) : Py_TAG_PTR;
+    unsigned int tag = (obj == NULL || _Py_IsImmortal(obj)) ? (Py_TAG_DEFERRED) : Py_TAG_PTR;
     return ((_PyStackRef){.bits = ((uintptr_t)(obj)) | tag});
 }
 #   define PyStackRef_FromPyObjectSteal(obj) _PyStackRef_FromPyObjectSteal(_PyObject_CAST(obj))

Tools/build/.warningignore_macos

@@ -6,7 +6,6 @@
 Include/internal/mimalloc/mimalloc/internal.h 4
 Include/internal/pycore_backoff.h 1
 Include/internal/pycore_dict.h 2
-Include/internal/pycore_gc.h 1
 Include/internal/pycore_long.h 2
 Include/internal/pycore_object.h 4
 Modules/_asynciomodule.c 3

Tools/build/.warningignore_ubuntu

@@ -19,10 +19,7 @@ Include/internal/pycore_asdl.h 1
 Include/internal/pycore_backoff.h 3
 Include/internal/pycore_blocks_output_buffer.h 1
 Include/internal/pycore_dict.h 2
-Include/internal/pycore_gc.h 1
-Include/internal/pycore_gc.h 1
 Include/internal/pycore_interp.h 1
-Include/internal/pycore_list.h 1
 Include/internal/pycore_long.h 3
 Include/internal/pycore_object.h 4
 Include/internal/pycore_obmalloc.h 1
@@ -233,7 +230,6 @@ Python/generated_cases.c.h 27
 Python/generated_cases.c.h 27
 Python/getargs.c 7
 Python/hashtable.c 1
-Python/import.c 6
 Python/import.c 7
 Python/initconfig.c 11
 Python/instrumentation.c 43