diff --git a/.github/workflows/analysis.yml b/.github/workflows/analysis.yml
index 6260643a4da..d3a04488d0b 100644
--- a/.github/workflows/analysis.yml
+++ b/.github/workflows/analysis.yml
@@ -414,6 +414,7 @@ jobs:
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_JAVA:BOOL=OFF")
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_CPP_LIB:BOOL=ON")
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_BUILD_FORTRAN:BOOL=OFF")
+              set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_NONSTANDARD_FEATURE_FLOAT16:BOOL=OFF")
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_SANITIZERS:BOOL=ON")
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_USE_SANITIZER:STRING=Undefined")
               set (ADD_BUILD_OPTIONS "${ADD_BUILD_OPTIONS} -DHDF5_ENABLE_ZLIB_SUPPORT:BOOL=OFF")
diff --git a/src/H5Aint.c b/src/H5Aint.c
index b65d014add2..c58fde69e98 100644
--- a/src/H5Aint.c
+++ b/src/H5Aint.c
@@ -72,7 +72,7 @@ typedef struct {
 /* Local Prototypes */
 /********************/
 
-static herr_t H5A__close_cb(H5VL_object_t *attr_vol_obj, void **request);
+static herr_t H5A__close_cb(void *attr_vol_obj, void **request);
 static herr_t H5A__compact_build_table_cb(H5O_t *oh, H5O_mesg_t *mesg /*in,out*/, unsigned sequence,
                                           void *_udata /*in,out*/);
 static herr_t H5A__dense_build_table_cb(const H5A_t *attr, void *_udata);
@@ -124,10 +124,10 @@ H5FL_SEQ_DEFINE_STATIC(H5A_t_ptr);
 
 /* Attribute ID class */
 static const H5I_class_t H5I_ATTR_CLS[1] = {{
-    H5I_ATTR,                 /* ID class value */
-    0,                        /* Class flags */
-    0,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5A__close_cb /* Callback routine for closing objects of this class */
+    H5I_ATTR,     /* ID class value */
+    0,            /* Class flags */
+    0,            /* # of reserved IDs for class */
+    H5A__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -1277,21 +1277,22 @@ H5A__shared_free(H5A_t *attr)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5A__close_cb(H5VL_object_t *attr_vol_obj, void **request)
+H5A__close_cb(void *attr_vol_obj, void **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_object_t *attr_vol_obj_p = (H5VL_object_t *)attr_vol_obj;
+    herr_t         ret_value      = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(attr_vol_obj);
+    assert(attr_vol_obj_p);
 
     /* Close the attribute */
-    if (H5VL_attr_close(attr_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
+    if (H5VL_attr_close(attr_vol_obj_p, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CLOSEERROR, FAIL, "problem closing attribute");
 
     /* Free the VOL object */
-    if (H5VL_free_object(attr_vol_obj) < 0)
+    if (H5VL_free_object(attr_vol_obj_p) < 0)
         HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to free VOL object");
 
 done:
diff --git a/src/H5Dint.c b/src/H5Dint.c
index f277677bc48..94c9a4325a8 100644
--- a/src/H5Dint.c
+++ b/src/H5Dint.c
@@ -84,7 +84,7 @@ static herr_t H5D__build_file_prefix(const H5D_t *dset, H5F_prefix_open_t prefix
 static herr_t H5D__open_oid(H5D_t *dataset, hid_t dapl_id);
 static herr_t H5D__init_storage(H5D_t *dset, bool full_overwrite, hsize_t old_dim[]);
 static herr_t H5D__append_flush_setup(H5D_t *dset, hid_t dapl_id);
-static herr_t H5D__close_cb(H5VL_object_t *dset_vol_obj, void **request);
+static herr_t H5D__close_cb(void *dset_vol_obj, void **request);
 static herr_t H5D__use_minimized_dset_headers(H5F_t *file, bool *minimize);
 static herr_t H5D__prepare_minimized_oh(H5F_t *file, H5D_t *dset, H5O_loc_t *oloc);
 static size_t H5D__calculate_minimum_header_size(H5F_t *file, H5D_t *dset, H5O_t *ohdr);
@@ -133,10 +133,10 @@ H5_WARN_LARGE_STACK_OBJECTS_ON
 
 /* Dataset ID class */
 static const H5I_class_t H5I_DATASET_CLS[1] = {{
-    H5I_DATASET,              /* ID class value */
-    0,                        /* Class flags */
-    0,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5D__close_cb /* Callback routine for closing objects of this class */
+    H5I_DATASET,  /* ID class value */
+    0,            /* Class flags */
+    0,            /* # of reserved IDs for class */
+    H5D__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -332,22 +332,23 @@ H5D_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5D__close_cb(H5VL_object_t *dset_vol_obj, void **request)
+H5D__close_cb(void *dset_vol_obj, void **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_object_t *dset_vol_obj_p = (H5VL_object_t *)dset_vol_obj;
+    herr_t         ret_value      = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(dset_vol_obj);
+    assert(dset_vol_obj_p);
 
     /* Close the dataset */
-    if (H5VL_dataset_close(dset_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
+    if (H5VL_dataset_close(dset_vol_obj_p, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CLOSEERROR, FAIL, "unable to close dataset");
 
 done:
     /* Free the VOL object */
-    if (H5VL_free_object(dset_vol_obj) < 0)
+    if (H5VL_free_object(dset_vol_obj_p) < 0)
         HGOTO_ERROR(H5E_DATASET, H5E_CANTDEC, FAIL, "unable to free VOL object");
 
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Dscatgath.c b/src/H5Dscatgath.c
index 56b556615a8..5e7822c229d 100644
--- a/src/H5Dscatgath.c
+++ b/src/H5Dscatgath.c
@@ -1264,12 +1264,21 @@ H5D__scatgath_write_select(H5D_io_info_t *io_info)
 
             if ((H5T_BKG_YES == dset_info->type_info.need_bkg) &&
                 !H5D__SCATGATH_USE_CMPD_OPT_WRITE(dset_info, io_info->sel_pieces[i]->in_place_tconv)) {
-                /* Non-const write_buf[i].  Use pointer math here to avoid const warnings.  When
-                 * there's a background buffer write_buf[i] always points inside the non-const tconv
-                 * buf so this is OK. */
-                void *tmp_write_buf =
-                    (void *)((uint8_t *)io_info->tconv_buf +
-                             ((const uint8_t *)write_bufs[i] - (const uint8_t *)io_info->tconv_buf));
+                void *tmp_write_buf;
+
+                if (io_info->sel_pieces[i]->in_place_tconv) {
+                    H5_flexible_const_ptr_t flex_buf = {.cvp = write_bufs[i]};
+
+                    tmp_write_buf = flex_buf.vp;
+                }
+                else {
+                    /* Non-const write_buf[i].  Use pointer math here to avoid const warnings.  When
+                     * there's a background buffer write_buf[i] always points inside the non-const tconv
+                     * buf so this is OK. */
+                    tmp_write_buf =
+                        (void *)((uint8_t *)io_info->tconv_buf +
+                                 ((const uint8_t *)write_bufs[i] - (const uint8_t *)io_info->tconv_buf));
+                }
 
                 /* Do the data transform before the type conversion (since
                  * transforms must be done in the memory type). */
diff --git a/src/H5EA.c b/src/H5EA.c
index 09258449a4c..9bbd9d46fe0 100644
--- a/src/H5EA.c
+++ b/src/H5EA.c
@@ -340,7 +340,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
     *thing             = NULL;
     *thing_elmt_buf    = NULL;
     *thing_elmt_idx    = 0;
-    *thing_unprot_func = (H5EA__unprotect_func_t)NULL;
+    *thing_unprot_func = NULL;
 
     /* Check if we should create the index block */
     if (!H5_addr_defined(hdr->idx_blk_addr)) {
@@ -368,7 +368,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
         *thing             = iblock;
         *thing_elmt_buf    = (uint8_t *)iblock->elmts;
         *thing_elmt_idx    = idx;
-        *thing_unprot_func = (H5EA__unprotect_func_t)H5EA__iblock_unprotect;
+        *thing_unprot_func = H5EA__iblock_unprotect;
     } /* end if */
     else {
         unsigned sblk_idx; /* Which superblock does this index fall in? */
@@ -436,7 +436,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
             *thing             = dblock;
             *thing_elmt_buf    = (uint8_t *)dblock->elmts;
             *thing_elmt_idx    = elmt_idx;
-            *thing_unprot_func = (H5EA__unprotect_func_t)H5EA__dblock_unprotect;
+            *thing_unprot_func = H5EA__dblock_unprotect;
         } /* end if */
         else {
             size_t sblk_off; /* Offset of super block in index block array of super blocks */
@@ -569,7 +569,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
                 *thing             = dblk_page;
                 *thing_elmt_buf    = (uint8_t *)dblk_page->elmts;
                 *thing_elmt_idx    = elmt_idx;
-                *thing_unprot_func = (H5EA__unprotect_func_t)H5EA__dblk_page_unprotect;
+                *thing_unprot_func = H5EA__dblk_page_unprotect;
             } /* end if */
             else {
                 /* Protect data block */
@@ -593,7 +593,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
                 *thing             = dblock;
                 *thing_elmt_buf    = (uint8_t *)dblock->elmts;
                 *thing_elmt_idx    = elmt_idx;
-                *thing_unprot_func = (H5EA__unprotect_func_t)H5EA__dblock_unprotect;
+                *thing_unprot_func = H5EA__dblock_unprotect;
             } /* end else */
         }     /* end else */
     }         /* end else */
@@ -608,7 +608,7 @@ H5EA__lookup_elmt(const H5EA_t *ea, hsize_t idx, bool will_extend, unsigned thin
         *thing             = NULL;
         *thing_elmt_buf    = NULL;
         *thing_elmt_idx    = 0;
-        *thing_unprot_func = (H5EA__unprotect_func_t)NULL;
+        *thing_unprot_func = NULL;
     } /* end if */
 
     /* Check for updating array statistics */
diff --git a/src/H5EAdblkpage.c b/src/H5EAdblkpage.c
index a18dbcc4e70..0bb9d354ff6 100644
--- a/src/H5EAdblkpage.c
+++ b/src/H5EAdblkpage.c
@@ -257,9 +257,10 @@ H5EA__dblk_page_protect(H5EA_hdr_t *hdr, H5EA_sblock_t *parent, haddr_t dblk_pag
  *-------------------------------------------------------------------------
  */
 herr_t
-H5EA__dblk_page_unprotect(H5EA_dblk_page_t *dblk_page, unsigned cache_flags)
+H5EA__dblk_page_unprotect(void *_dblk_page, unsigned cache_flags)
 {
-    herr_t ret_value = SUCCEED;
+    H5EA_dblk_page_t *dblk_page = (H5EA_dblk_page_t *)_dblk_page;
+    herr_t            ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
 
diff --git a/src/H5EAdblock.c b/src/H5EAdblock.c
index 7b0298b4379..17b04966f44 100644
--- a/src/H5EAdblock.c
+++ b/src/H5EAdblock.c
@@ -336,9 +336,10 @@ H5EA__dblock_protect(H5EA_hdr_t *hdr, void *parent, haddr_t dblk_addr, size_t db
  *-------------------------------------------------------------------------
  */
 herr_t
-H5EA__dblock_unprotect(H5EA_dblock_t *dblock, unsigned cache_flags)
+H5EA__dblock_unprotect(void *_dblock, unsigned cache_flags)
 {
-    herr_t ret_value = SUCCEED;
+    H5EA_dblock_t *dblock    = (H5EA_dblock_t *)_dblock;
+    herr_t         ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
 
diff --git a/src/H5EAiblock.c b/src/H5EAiblock.c
index 4d007153fda..0896a9d42af 100644
--- a/src/H5EAiblock.c
+++ b/src/H5EAiblock.c
@@ -324,9 +324,10 @@ H5EA__iblock_protect(H5EA_hdr_t *hdr, unsigned flags)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5EA__iblock_unprotect(H5EA_iblock_t *iblock, unsigned cache_flags)
+H5EA__iblock_unprotect(void *_iblock, unsigned cache_flags)
 {
-    herr_t ret_value = SUCCEED;
+    H5EA_iblock_t *iblock    = (H5EA_iblock_t *)_iblock;
+    herr_t         ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
 
diff --git a/src/H5EApkg.h b/src/H5EApkg.h
index 5bcb823e17f..e73ba8af462 100644
--- a/src/H5EApkg.h
+++ b/src/H5EApkg.h
@@ -406,7 +406,7 @@ H5_DLL herr_t      H5EA__hdr_dest(H5EA_hdr_t *hdr);
 H5_DLL H5EA_iblock_t *H5EA__iblock_alloc(H5EA_hdr_t *hdr);
 H5_DLL haddr_t        H5EA__iblock_create(H5EA_hdr_t *hdr, bool *stats_changed);
 H5_DLL H5EA_iblock_t *H5EA__iblock_protect(H5EA_hdr_t *hdr, unsigned flags);
-H5_DLL herr_t         H5EA__iblock_unprotect(H5EA_iblock_t *iblock, unsigned cache_flags);
+H5_DLL herr_t         H5EA__iblock_unprotect(void *_iblock, unsigned cache_flags);
 H5_DLL herr_t         H5EA__iblock_delete(H5EA_hdr_t *hdr);
 H5_DLL herr_t         H5EA__iblock_dest(H5EA_iblock_t *iblock);
 
@@ -428,7 +428,7 @@ H5_DLL haddr_t  H5EA__dblock_create(H5EA_hdr_t *hdr, void *parent, bool *stats_c
 H5_DLL unsigned H5EA__dblock_sblk_idx(const H5EA_hdr_t *hdr, hsize_t idx);
 H5_DLL H5EA_dblock_t *H5EA__dblock_protect(H5EA_hdr_t *hdr, void *parent, haddr_t dblk_addr,
                                            size_t dblk_nelmts, unsigned flags);
-H5_DLL herr_t         H5EA__dblock_unprotect(H5EA_dblock_t *dblock, unsigned cache_flags);
+H5_DLL herr_t         H5EA__dblock_unprotect(void *_dblock, unsigned cache_flags);
 H5_DLL herr_t H5EA__dblock_delete(H5EA_hdr_t *hdr, void *parent, haddr_t dblk_addr, size_t dblk_nelmts);
 H5_DLL herr_t H5EA__dblock_dest(H5EA_dblock_t *dblock);
 
@@ -437,7 +437,7 @@ H5_DLL H5EA_dblk_page_t *H5EA__dblk_page_alloc(H5EA_hdr_t *hdr, H5EA_sblock_t *p
 H5_DLL herr_t            H5EA__dblk_page_create(H5EA_hdr_t *hdr, H5EA_sblock_t *parent, haddr_t addr);
 H5_DLL H5EA_dblk_page_t *H5EA__dblk_page_protect(H5EA_hdr_t *hdr, H5EA_sblock_t *parent,
                                                  haddr_t dblk_page_addr, unsigned flags);
-H5_DLL herr_t            H5EA__dblk_page_unprotect(H5EA_dblk_page_t *dblk_page, unsigned cache_flags);
+H5_DLL herr_t            H5EA__dblk_page_unprotect(void *_dblk_page, unsigned cache_flags);
 H5_DLL herr_t            H5EA__dblk_page_dest(H5EA_dblk_page_t *dblk_page);
 
 /* Debugging routines for dumping file structures */
diff --git a/src/H5ESint.c b/src/H5ESint.c
index 655fb818c04..e15a4cfa122 100644
--- a/src/H5ESint.c
+++ b/src/H5ESint.c
@@ -116,10 +116,10 @@ bool H5_PKG_INIT_VAR = false;
 
 /* Event Set ID class */
 static const H5I_class_t H5I_EVENTSET_CLS[1] = {{
-    H5I_EVENTSET,              /* ID class value */
-    0,                         /* Class flags */
-    0,                         /* # of reserved IDs for class */
-    (H5I_free_t)H5ES__close_cb /* Callback routine for closing objects of this class */
+    H5I_EVENTSET,  /* ID class value */
+    0,             /* Class flags */
+    0,             /* # of reserved IDs for class */
+    H5ES__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Declare a static free list to manage H5ES_t structs */
diff --git a/src/H5Eint.c b/src/H5Eint.c
index f3059b4893c..491684613b6 100644
--- a/src/H5Eint.c
+++ b/src/H5Eint.c
@@ -68,11 +68,11 @@ static herr_t H5E__copy_stack_entry(H5E_entry_t *dst_entry, const H5E_entry_t *s
 static herr_t H5E__set_stack_entry(H5E_error2_t *err_entry, const char *file, const char *func, unsigned line,
                                    hid_t cls_id, hid_t maj_id, hid_t min_id, const char *desc, va_list *ap);
 static herr_t H5E__clear_entries(H5E_stack_t *estack, size_t nentries);
-static herr_t H5E__unregister_class(H5E_cls_t *cls, void **request);
+static herr_t H5E__unregister_class(void *cls, void **request);
 static int    H5E__close_msg_cb(void *obj_ptr, hid_t obj_id, void *udata);
 static void   H5E__free_msg(H5E_msg_t *msg);
-static herr_t H5E__close_msg(H5E_msg_t *err, void **request);
-static herr_t H5E__close_stack(H5E_stack_t *err_stack, void **request);
+static herr_t H5E__close_msg(void *err, void **request);
+static herr_t H5E__close_stack(void *err_stack, void **request);
 
 /*********************/
 /* Package Variables */
@@ -174,26 +174,26 @@ hid_t H5E_last_min_id_g  = H5I_INVALID_HID;
 
 /* Error class ID class */
 static const H5I_class_t H5I_ERRCLS_CLS[1] = {{
-    H5I_ERROR_CLASS,                  /* ID class value */
-    0,                                /* Class flags */
-    0,                                /* # of reserved IDs for class */
-    (H5I_free_t)H5E__unregister_class /* Callback routine for closing objects of this class */
+    H5I_ERROR_CLASS,      /* ID class value */
+    0,                    /* Class flags */
+    0,                    /* # of reserved IDs for class */
+    H5E__unregister_class /* Callback routine for closing objects of this class */
 }};
 
 /* Error message ID class */
 static const H5I_class_t H5I_ERRMSG_CLS[1] = {{
-    H5I_ERROR_MSG,             /* ID class value */
-    0,                         /* Class flags */
-    0,                         /* # of reserved IDs for class */
-    (H5I_free_t)H5E__close_msg /* Callback routine for closing objects of this class */
+    H5I_ERROR_MSG, /* ID class value */
+    0,             /* Class flags */
+    0,             /* # of reserved IDs for class */
+    H5E__close_msg /* Callback routine for closing objects of this class */
 }};
 
 /* Error stack ID class */
 static const H5I_class_t H5I_ERRSTK_CLS[1] = {{
-    H5I_ERROR_STACK,             /* ID class value */
-    0,                           /* Class flags */
-    0,                           /* # of reserved IDs for class */
-    (H5I_free_t)H5E__close_stack /* Callback routine for closing objects of this class */
+    H5I_ERROR_STACK, /* ID class value */
+    0,               /* Class flags */
+    0,               /* # of reserved IDs for class */
+    H5E__close_stack /* Callback routine for closing objects of this class */
 }};
 
 /* Library's error class */
@@ -519,21 +519,22 @@ H5E__register_class(const char *cls_name, const char *lib_name, const char *vers
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__unregister_class(H5E_cls_t *cls, void H5_ATTR_UNUSED **request)
+H5E__unregister_class(void *cls, void H5_ATTR_UNUSED **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5E_cls_t *cls_p     = (H5E_cls_t *)cls;
+    herr_t     ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Check arguments */
-    assert(cls);
+    assert(cls_p);
 
     /* Iterate over all the messages and delete those in this error class */
-    if (H5I_iterate(H5I_ERROR_MSG, H5E__close_msg_cb, cls, false) < 0)
+    if (H5I_iterate(H5I_ERROR_MSG, H5E__close_msg_cb, cls_p, false) < 0)
         HGOTO_ERROR(H5E_ERROR, H5E_BADITER, FAIL, "unable to free all messages in this error class");
 
     /* Free error class structure */
-    if (H5E__free_class(cls) < 0)
+    if (H5E__free_class(cls_p) < 0)
         HGOTO_ERROR(H5E_ERROR, H5E_CANTRELEASE, FAIL, "unable to free error class");
 
 done:
@@ -644,17 +645,19 @@ H5E__free_msg(H5E_msg_t *msg)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__close_msg(H5E_msg_t *err, void H5_ATTR_UNUSED **request)
+H5E__close_msg(void *err, void H5_ATTR_UNUSED **request)
 {
+    H5E_msg_t *err_p = (H5E_msg_t *)err;
+
     FUNC_ENTER_PACKAGE_NOERR
 
     /* Check arguments */
-    assert(err);
+    assert(err_p);
 
     /* Free resources, if application registered this message */
-    if (err->app_msg)
+    if (err_p->app_msg)
         /* Free message */
-        H5E__free_msg(err);
+        H5E__free_msg(err_p);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5E__close_msg() */
@@ -804,18 +807,20 @@ H5E__set_current_stack(H5E_stack_t *estack)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5E__close_stack(H5E_stack_t *estack, void H5_ATTR_UNUSED **request)
+H5E__close_stack(void *estack, void H5_ATTR_UNUSED **request)
 {
+    H5E_stack_t *estack_p = (H5E_stack_t *)estack;
+
     FUNC_ENTER_PACKAGE_NOERR
 
     /* Sanity check */
-    assert(estack);
+    assert(estack_p);
 
     /* Release the stack's error information */
-    H5E__destroy_stack(estack);
+    H5E__destroy_stack(estack_p);
 
     /* Free the stack structure */
-    estack = H5FL_FREE(H5E_stack_t, estack);
+    estack_p = H5FL_FREE(H5E_stack_t, estack_p);
 
     FUNC_LEAVE_NOAPI(SUCCEED)
 } /* end H5E__close_stack() */
diff --git a/src/H5FD.c b/src/H5FD.c
index 45f3c6d57dc..7a523af28ed 100644
--- a/src/H5FD.c
+++ b/src/H5FD.c
@@ -52,7 +52,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5FD__free_cls(H5FD_class_t *cls, void **request);
+static herr_t H5FD__free_cls(void *cls, void **request);
 static herr_t H5FD__query(const H5FD_t *f, unsigned long *flags /*out*/);
 
 /*********************/
@@ -89,10 +89,10 @@ static unsigned long H5FD_file_serial_no_g;
 
 /* File driver ID class */
 static const H5I_class_t H5I_VFL_CLS[1] = {{
-    H5I_VFL,                   /* ID class value */
-    0,                         /* Class flags */
-    0,                         /* # of reserved IDs for class */
-    (H5I_free_t)H5FD__free_cls /* Callback routine for closing objects of this class */
+    H5I_VFL,       /* ID class value */
+    0,             /* Class flags */
+    0,             /* # of reserved IDs for class */
+    H5FD__free_cls /* Callback routine for closing objects of this class */
 }};
 
 /*-------------------------------------------------------------------------
@@ -283,32 +283,33 @@ H5FD_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5FD__free_cls(H5FD_class_t *cls, void H5_ATTR_UNUSED **request)
+H5FD__free_cls(void *cls, void H5_ATTR_UNUSED **request)
 {
-    herr_t ret_value = SUCCEED;
+    H5FD_class_t *cls_p     = (H5FD_class_t *)cls;
+    herr_t        ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity checks */
-    assert(cls);
+    assert(cls_p);
 
     /* If the file driver has a terminate callback, call it to give the file
      * driver a chance to free singletons or other resources which will become
      * invalid once the class structure is freed.
      */
-    if (cls->terminate) {
+    if (cls_p->terminate) {
         /* Prepare & restore library for user callback */
         H5_BEFORE_USER_CB(FAIL)
             {
-                ret_value = cls->terminate();
+                ret_value = cls_p->terminate();
             }
         H5_AFTER_USER_CB(FAIL)
         if (ret_value < 0)
             HGOTO_ERROR(H5E_VFL, H5E_CANTCLOSEOBJ, FAIL, "virtual file driver '%s' did not terminate cleanly",
-                        cls->name);
+                        cls_p->name);
     }
 
-    H5MM_xfree(cls);
+    H5MM_xfree(cls_p);
 
 done:
     FUNC_LEAVE_NOAPI(ret_value)
diff --git a/src/H5Fint.c b/src/H5Fint.c
index 1364ed9d89e..0409160dc71 100644
--- a/src/H5Fint.c
+++ b/src/H5Fint.c
@@ -71,7 +71,7 @@ typedef struct H5F_olist_t {
 /* Local Prototypes */
 /********************/
 
-static herr_t H5F__close_cb(H5VL_object_t *file_vol_obj, void **request);
+static herr_t H5F__close_cb(void *file_vol_obj, void **request);
 static herr_t H5F__set_vol_conn(H5F_t *file);
 static herr_t H5F__get_objects(const H5F_t *f, unsigned types, size_t max_index, hid_t *obj_id_list,
                                bool app_ref, size_t *obj_id_count_ptr);
@@ -117,10 +117,10 @@ H5FL_DEFINE(H5F_shared_t);
 
 /* File ID class */
 static const H5I_class_t H5I_FILE_CLS[1] = {{
-    H5I_FILE,                 /* ID class value */
-    0,                        /* Class flags */
-    0,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5F__close_cb /* Callback routine for closing objects of this class */
+    H5I_FILE,     /* ID class value */
+    0,            /* Class flags */
+    0,            /* # of reserved IDs for class */
+    H5F__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /*-------------------------------------------------------------------------
@@ -236,22 +236,23 @@ H5F_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5F__close_cb(H5VL_object_t *file_vol_obj, void **request)
+H5F__close_cb(void *file_vol_obj, void **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_object_t *file_vol_obj_p = (H5VL_object_t *)file_vol_obj;
+    herr_t         ret_value      = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(file_vol_obj);
+    assert(file_vol_obj_p);
 
     /* Close the file */
-    if (H5VL_file_close(file_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
+    if (H5VL_file_close(file_vol_obj_p, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTCLOSEFILE, FAIL, "unable to close file");
 
     /* Free the VOL object; it is unnecessary to unwrap the VOL
      * object before freeing it, as the object was not wrapped */
-    if (H5VL_free_object(file_vol_obj) < 0)
+    if (H5VL_free_object(file_vol_obj_p) < 0)
         HGOTO_ERROR(H5E_FILE, H5E_CANTDEC, FAIL, "unable to free VOL object");
 
 done:
diff --git a/src/H5Gint.c b/src/H5Gint.c
index 598658408ce..8d5f9842e15 100644
--- a/src/H5Gint.c
+++ b/src/H5Gint.c
@@ -84,7 +84,7 @@ typedef struct {
 
 static herr_t H5G__open_oid(H5G_t *grp);
 static herr_t H5G__visit_cb(const H5O_link_t *lnk, void *_udata);
-static herr_t H5G__close_cb(H5VL_object_t *grp_vol_obj, void **request);
+static herr_t H5G__close_cb(void *grp_vol_obj, void **request);
 
 /*********************/
 /* Package Variables */
@@ -110,10 +110,10 @@ H5FL_DEFINE(H5_obj_t);
 
 /* Group ID class */
 static const H5I_class_t H5I_GROUP_CLS[1] = {{
-    H5I_GROUP,                /* ID class value */
-    0,                        /* Class flags */
-    0,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5G__close_cb /* Callback routine for closing objects of this class */
+    H5I_GROUP,    /* ID class value */
+    0,            /* Class flags */
+    0,            /* # of reserved IDs for class */
+    H5G__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -257,21 +257,22 @@ H5G_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5G__close_cb(H5VL_object_t *grp_vol_obj, void **request)
+H5G__close_cb(void *grp_vol_obj, void **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_object_t *grp_vol_obj_p = (H5VL_object_t *)grp_vol_obj;
+    herr_t         ret_value     = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(grp_vol_obj);
+    assert(grp_vol_obj_p);
 
     /* Close the group */
-    if (H5VL_group_close(grp_vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
+    if (H5VL_group_close(grp_vol_obj_p, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CLOSEERROR, FAIL, "unable to close group");
 
     /* Free the VOL object */
-    if (H5VL_free_object(grp_vol_obj) < 0)
+    if (H5VL_free_object(grp_vol_obj_p) < 0)
         HGOTO_ERROR(H5E_SYM, H5E_CANTDEC, FAIL, "unable to free VOL object");
 
 done:
diff --git a/src/H5M.c b/src/H5M.c
index beea264fea0..0ff69100913 100644
--- a/src/H5M.c
+++ b/src/H5M.c
@@ -38,7 +38,7 @@
 /********************/
 /* Local Prototypes */
 /********************/
-static herr_t H5M__close_cb(H5VL_object_t *map_vol_obj, void **request);
+static herr_t H5M__close_cb(void *map_vol_obj, void **request);
 
 #ifdef H5_HAVE_MAP_API
 static hid_t  H5M__create_api_common(hid_t loc_id, const char *name, hid_t key_type_id, hid_t val_type_id,
@@ -70,10 +70,10 @@ bool H5_PKG_INIT_VAR = false;
 
 /* Map ID class */
 static const H5I_class_t H5I_MAP_CLS[1] = {{
-    H5I_MAP,                  /* ID class value */
-    0,                        /* Class flags */
-    0,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5M__close_cb /* Callback routine for closing objects of this class */
+    H5I_MAP,      /* ID class value */
+    0,            /* Class flags */
+    0,            /* # of reserved IDs for class */
+    H5M__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -207,26 +207,27 @@ H5M_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5M__close_cb(H5VL_object_t *map_vol_obj, void **request)
+H5M__close_cb(void *map_vol_obj, void **request)
 {
-    H5VL_optional_args_t vol_cb_args;         /* Arguments to VOL callback */
-    herr_t               ret_value = SUCCEED; /* Return value */
+    H5VL_optional_args_t vol_cb_args; /* Arguments to VOL callback */
+    H5VL_object_t       *map_vol_obj_p = (H5VL_object_t *)map_vol_obj;
+    herr_t               ret_value     = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(map_vol_obj);
+    assert(map_vol_obj_p);
 
     /* Set up VOL callback arguments */
     vol_cb_args.op_type = H5VL_MAP_CLOSE;
     vol_cb_args.args    = NULL;
 
     /* Close the map */
-    if (H5VL_optional(map_vol_obj, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, request) < 0)
+    if (H5VL_optional(map_vol_obj_p, &vol_cb_args, H5P_DATASET_XFER_DEFAULT, request) < 0)
         HGOTO_ERROR(H5E_MAP, H5E_CLOSEERROR, FAIL, "unable to close map");
 
     /* Free the VOL object */
-    if (H5VL_free_object(map_vol_obj) < 0)
+    if (H5VL_free_object(map_vol_obj_p) < 0)
         HGOTO_ERROR(H5E_MAP, H5E_CANTDEC, FAIL, "unable to free VOL object");
 
 done:
diff --git a/src/H5Odtype.c b/src/H5Odtype.c
index 3273b7a63b7..28c8b904ec6 100644
--- a/src/H5Odtype.c
+++ b/src/H5Odtype.c
@@ -1490,7 +1490,7 @@ H5O__dtype_decode(H5F_t *f, H5O_t *open_oh, unsigned H5_ATTR_UNUSED mesg_flags,
 {
     bool           skip;
     H5T_t         *dt        = NULL;
-    const uint8_t *p_end     = p + p_size - 1;
+    const uint8_t *p_end     = NULL;
     void          *ret_value = NULL;
 
     FUNC_ENTER_PACKAGE
@@ -1508,6 +1508,10 @@ H5O__dtype_decode(H5F_t *f, H5O_t *open_oh, unsigned H5_ATTR_UNUSED mesg_flags,
      * as a signal to skip bounds checking.
      */
     skip = (p_size == SIZE_MAX ? true : false);
+    if (skip)
+        p_end = p;
+    else
+        p_end = p + p_size - 1;
 
     /* Indicate if the object header has a checksum, or if the
      * H5F_RFIC_UNUSUAL_NUM_UNUSED_NUMERIC_BITS flag is set */
diff --git a/src/H5Pint.c b/src/H5Pint.c
index 0cacaf79527..aec4cc71cfa 100644
--- a/src/H5Pint.c
+++ b/src/H5Pint.c
@@ -393,18 +393,18 @@ H5FL_DEFINE_STATIC(H5P_genplist_t);
 
 /* Generic Property Class ID class */
 static const H5I_class_t H5I_GENPROPCLS_CLS[1] = {{
-    H5I_GENPROP_CLS,                /* ID class value */
-    0,                              /* Class flags */
-    0,                              /* # of reserved IDs for class */
-    (H5I_free_t)H5P__close_class_cb /* Callback routine for closing objects of this class */
+    H5I_GENPROP_CLS,    /* ID class value */
+    0,                  /* Class flags */
+    0,                  /* # of reserved IDs for class */
+    H5P__close_class_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Generic Property List ID class */
 static const H5I_class_t H5I_GENPROPLST_CLS[1] = {{
-    H5I_GENPROP_LST,               /* ID class value */
-    0,                             /* Class flags */
-    0,                             /* # of reserved IDs for class */
-    (H5I_free_t)H5P__close_list_cb /* Callback routine for closing objects of this class */
+    H5I_GENPROP_LST,   /* ID class value */
+    0,                 /* Class flags */
+    0,                 /* # of reserved IDs for class */
+    H5P__close_list_cb /* Callback routine for closing objects of this class */
 }};
 
 /*-------------------------------------------------------------------------
diff --git a/src/H5S.c b/src/H5S.c
index 789ea606d69..17b816f50f4 100644
--- a/src/H5S.c
+++ b/src/H5S.c
@@ -83,18 +83,18 @@ H5FL_ARR_DEFINE(hsize_t, H5S_MAX_RANK);
 
 /* Dataspace ID class */
 static const H5I_class_t H5I_DATASPACE_CLS[1] = {{
-    H5I_DATASPACE,            /* ID class value */
-    0,                        /* Class flags */
-    3,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5S__close_cb /* Callback routine for closing objects of this class */
+    H5I_DATASPACE, /* ID class value */
+    0,             /* Class flags */
+    3,             /* # of reserved IDs for class */
+    H5S__close_cb  /* Callback routine for closing objects of this class */
 }};
 
 /* Dataspace selection iterator ID class */
 static const H5I_class_t H5I_SPACE_SEL_ITER_CLS[1] = {{
-    H5I_SPACE_SEL_ITER,                /* ID class value */
-    0,                                 /* Class flags */
-    0,                                 /* # of reserved IDs for class */
-    (H5I_free_t)H5S__sel_iter_close_cb /* Callback routine for closing objects of this class */
+    H5I_SPACE_SEL_ITER,    /* ID class value */
+    0,                     /* Class flags */
+    0,                     /* # of reserved IDs for class */
+    H5S__sel_iter_close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
diff --git a/src/H5Sall.c b/src/H5Sall.c
index 8bdcc4ad9aa..4dc7465a8dc 100644
--- a/src/H5Sall.c
+++ b/src/H5Sall.c
@@ -624,16 +624,21 @@ H5S__all_serialize(H5S_t *space, uint8_t **p)
 static herr_t
 H5S__all_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size, bool skip)
 {
-    uint32_t version;                           /* Version number */
-    H5S_t   *tmp_space = NULL;                  /* Pointer to actual dataspace to use,
-                                                   either *space or a newly allocated one */
-    herr_t         ret_value = SUCCEED;         /* return value */
-    const uint8_t *p_end     = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+    const uint8_t *p_end;
+    uint32_t       version;  /* Version number */
+    H5S_t *tmp_space = NULL; /* Pointer to actual dataspace to use, either *space or a newly allocated one */
+    herr_t ret_value = SUCCEED; /* return value */
+
     FUNC_ENTER_PACKAGE
 
     assert(p);
     assert(*p);
 
+    if (skip)
+        p_end = *p;
+    else
+        p_end = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+
     /* As part of the efforts to push all selection-type specific coding
        to the callbacks, the coding for the allocation of a null dataspace
        is moved from H5S_select_deserialize() in H5Sselect.c.
diff --git a/src/H5Shyper.c b/src/H5Shyper.c
index 2a147c96378..8af4b93f175 100644
--- a/src/H5Shyper.c
+++ b/src/H5Shyper.c
@@ -4240,19 +4240,20 @@ H5S__hyper_serialize(H5S_t *space, uint8_t **p)
 static herr_t
 H5S__hyper_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size, bool skip)
 {
-    H5S_t *tmp_space = NULL;                    /* Pointer to actual dataspace to use,
-                                                   either *space or a newly allocated one */
-    hsize_t        dims[H5S_MAX_RANK];          /* Dimension sizes */
-    hsize_t        start[H5S_MAX_RANK];         /* hyperslab start information */
-    hsize_t        block[H5S_MAX_RANK];         /* hyperslab block information */
-    uint32_t       version;                     /* Version number */
-    uint8_t        flags    = 0;                /* Flags */
-    uint8_t        enc_size = 0;                /* Encoded size of selection info */
-    unsigned       rank;                        /* rank of points */
-    const uint8_t *pp;                          /* Local pointer for decoding */
-    unsigned       u;                           /* Local counting variable */
-    herr_t         ret_value = FAIL;            /* return value */
-    const uint8_t *p_end     = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+    H5S_t *tmp_space = NULL;            /* Pointer to actual dataspace to use,
+                                           either *space or a newly allocated one */
+    hsize_t        dims[H5S_MAX_RANK];  /* Dimension sizes */
+    hsize_t        start[H5S_MAX_RANK]; /* hyperslab start information */
+    hsize_t        block[H5S_MAX_RANK]; /* hyperslab block information */
+    uint32_t       version;             /* Version number */
+    uint8_t        flags    = 0;        /* Flags */
+    uint8_t        enc_size = 0;        /* Encoded size of selection info */
+    unsigned       rank;                /* rank of points */
+    const uint8_t *pp;                  /* Local pointer for decoding */
+    unsigned       u;                   /* Local counting variable */
+    herr_t         ret_value = FAIL;    /* return value */
+    const uint8_t *p_end;
+
     FUNC_ENTER_PACKAGE
 
     /* Check args */
@@ -4260,6 +4261,11 @@ H5S__hyper_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size, bo
     pp = (*p);
     assert(pp);
 
+    if (skip)
+        p_end = *p;
+    else
+        p_end = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+
     /* As part of the efforts to push all selection-type specific coding
        to the callbacks, the coding for the allocation of a null dataspace
        is moved from H5S_select_deserialize() in H5Sselect.c to here.
diff --git a/src/H5Spkg.h b/src/H5Spkg.h
index 67125d874d6..35e9a15eb6e 100644
--- a/src/H5Spkg.h
+++ b/src/H5Spkg.h
@@ -396,7 +396,7 @@ H5_DLL herr_t H5S__hyper_project_intersection(H5S_t *src_space, H5S_t *dst_space
                                               H5S_t *proj_space, bool share_space);
 
 /* Operations on selection iterators */
-H5_DLL herr_t H5S__sel_iter_close_cb(H5S_sel_iter_t *_sel_iter, void **request);
+H5_DLL herr_t H5S__sel_iter_close_cb(void *_sel_iter, void **request);
 
 /* Testing functions */
 #ifdef H5S_TESTING
diff --git a/src/H5Spoint.c b/src/H5Spoint.c
index c8c226bee5a..22e73ed84a0 100644
--- a/src/H5Spoint.c
+++ b/src/H5Spoint.c
@@ -1363,8 +1363,9 @@ H5S__point_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size, bo
     unsigned       i, j;                     /* local counting variables */
     size_t         enc_type_size;
     size_t         coordinate_buffer_requirement;
-    herr_t         ret_value = SUCCEED;         /* Return value */
-    const uint8_t *p_end     = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+    herr_t         ret_value = SUCCEED; /* Return value */
+    const uint8_t *p_end;
+
     FUNC_ENTER_PACKAGE
 
     /* Check args */
@@ -1372,6 +1373,11 @@ H5S__point_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size, bo
     pp = (*p);
     assert(pp);
 
+    if (skip)
+        p_end = *p;
+    else
+        p_end = *p + p_size - 1; /* Pointer to last valid byte in buffer */
+
     /* As part of the efforts to push all selection-type specific coding
        to the callbacks, the coding for the allocation of a null dataspace
        is moved from H5S_select_deserialize() in H5Sselect.c to here.
diff --git a/src/H5Sselect.c b/src/H5Sselect.c
index a449041d7d1..e8f3ae4a206 100644
--- a/src/H5Sselect.c
+++ b/src/H5Sselect.c
@@ -523,14 +523,22 @@ H5S_select_valid(const H5S_t *space)
 herr_t
 H5S_select_deserialize(H5S_t **space, const uint8_t **p, const size_t p_size)
 {
-    uint32_t       sel_type;                                   /* Pointer to the selection type */
-    herr_t         ret_value = FAIL;                           /* Return value */
-    const uint8_t *p_end     = *p + p_size - 1;                /* Pointer to last valid byte in buffer */
-    bool           skip = (p_size == SIZE_MAX ? true : false); /* If p_size is unknown, skip buffer checks */
+    uint32_t       sel_type;         /* Pointer to the selection type */
+    herr_t         ret_value = FAIL; /* Return value */
+    const uint8_t *p_end     = NULL; /* Pointer to last valid byte in buffer */
+    bool           skip      = false;
+
     FUNC_ENTER_NOAPI(FAIL)
 
     assert(space);
 
+    /* If p_size is unknown, skip buffer checks */
+    skip = (p_size == SIZE_MAX ? true : false);
+    if (skip)
+        p_end = *p;
+    else
+        p_end = *p + p_size - 1;
+
     /* Selection-type specific coding is moved to the callbacks. */
 
     /* Decode selection type */
@@ -3069,7 +3077,7 @@ H5Ssel_iter_reset(hid_t sel_iter_id, hid_t space_id)
  *-------------------------------------------------------------------------
  */
 herr_t
-H5S__sel_iter_close_cb(H5S_sel_iter_t *_sel_iter, void H5_ATTR_UNUSED **request)
+H5S__sel_iter_close_cb(void *_sel_iter, void H5_ATTR_UNUSED **request)
 {
     H5S_sel_iter_t *sel_iter  = (H5S_sel_iter_t *)_sel_iter; /* The selection iterator to close */
     herr_t          ret_value = SUCCEED;                     /* Return value */
diff --git a/src/H5T.c b/src/H5T.c
index cbf68b2b90c..323cc8fcbaa 100644
--- a/src/H5T.c
+++ b/src/H5T.c
@@ -485,7 +485,7 @@ static herr_t H5T__register_int(H5T_pers_t pers, const char *name, H5T_t *src, H
 static herr_t H5T__register(H5T_pers_t pers, const char *name, H5T_t *src, H5T_t *dst, H5T_conv_func_t *conv);
 static htri_t H5T__compiler_conv(H5T_t *src, H5T_t *dst);
 static herr_t H5T__set_size(H5T_t *dt, size_t size);
-static herr_t H5T__close_cb(H5T_t *dt, void **request);
+static herr_t H5T__close_cb(void *dt, void **request);
 static herr_t H5T__init_path_table(void);
 static bool   H5T__path_table_search(const H5T_t *src, const H5T_t *dst, int *idx, int *last_cmp);
 static H5T_path_t *H5T__path_find_real(const H5T_t *src, const H5T_t *dst, const char *name,
@@ -767,10 +767,10 @@ H5FL_DEFINE_STATIC(H5T_path_t);
 
 /* Datatype ID class */
 static const H5I_class_t H5I_DATATYPE_CLS[1] = {{
-    H5I_DATATYPE,             /* ID class value */
-    0,                        /* Class flags    */
-    8,                        /* # of reserved IDs for class */
-    (H5I_free_t)H5T__close_cb /* Callback routine for closing objects of this class */
+    H5I_DATATYPE, /* ID class value */
+    0,            /* Class flags    */
+    8,            /* # of reserved IDs for class */
+    H5T__close_cb /* Callback routine for closing objects of this class */
 }};
 
 /* Flag indicating "top" of interface has been initialized */
@@ -2480,31 +2480,32 @@ H5T_term_package(void)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5T__close_cb(H5T_t *dt, void **request)
+H5T__close_cb(void *dt, void **request)
 {
+    H5T_t *dt_p      = (H5T_t *)dt;
     herr_t ret_value = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Sanity check */
-    assert(dt);
+    assert(dt_p);
 
     /* If this datatype is VOL-managed (i.e.: has a VOL object),
      * close it through the VOL connector.
      */
-    if (NULL != dt->vol_obj) {
+    if (NULL != dt_p->vol_obj) {
         /* Close the connector-managed datatype data */
-        if (H5VL_datatype_close(dt->vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
+        if (H5VL_datatype_close(dt_p->vol_obj, H5P_DATASET_XFER_DEFAULT, request) < 0)
             HGOTO_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, FAIL, "unable to close datatype");
 
         /* Free the VOL object */
-        if (H5VL_free_object(dt->vol_obj) < 0)
-            HGOTO_ERROR(H5E_ATTR, H5E_CANTDEC, FAIL, "unable to free VOL object");
-        dt->vol_obj = NULL;
+        if (H5VL_free_object(dt_p->vol_obj) < 0)
+            HGOTO_ERROR(H5E_DATATYPE, H5E_CANTDEC, FAIL, "unable to free VOL object");
+        dt_p->vol_obj = NULL;
     } /* end if */
 
     /* Close the datatype */
-    if (H5T_close(dt) < 0)
+    if (H5T_close(dt_p) < 0)
         HGOTO_ERROR(H5E_DATATYPE, H5E_CLOSEERROR, FAIL, "unable to close datatype");
 
 done:
diff --git a/src/H5Tref.c b/src/H5Tref.c
index 7f09fae24ea..2ee48d7cdba 100644
--- a/src/H5Tref.c
+++ b/src/H5Tref.c
@@ -641,11 +641,10 @@ H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size
                    H5VL_object_t H5_ATTR_UNUSED *dst_file, void *dst_buf,
                    size_t H5_ATTR_NDEBUG_UNUSED dst_size, void H5_ATTR_UNUSED *bg_buf)
 {
-    H5F_t          *src_f   = NULL;
-    hid_t           file_id = H5I_INVALID_HID;
-    H5R_ref_priv_t *dst_ref = (H5R_ref_priv_t *)dst_buf;
-    H5R_ref_priv_t  tmp_ref; /* Temporary reference to decode into */
-    herr_t          ret_value = SUCCEED;
+    H5F_t         *src_f   = NULL;
+    hid_t          file_id = H5I_INVALID_HID;
+    H5R_ref_priv_t tmp_ref; /* Temporary reference to decode into */
+    herr_t         ret_value = SUCCEED;
 
     FUNC_ENTER_PACKAGE
     H5T_REF_LOG_DEBUG("");
@@ -655,7 +654,6 @@ H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size
     assert(src_size);
     assert(dst_buf);
     assert(dst_size == H5T_REF_MEM_SIZE);
-    HDcompile_assert(sizeof(*dst_ref) == sizeof(tmp_ref));
 
     /* Memory-to-memory conversion to support vlen conversion */
     if (NULL == src_file) {
@@ -736,7 +734,7 @@ H5T__ref_mem_write(H5VL_object_t *src_file, const void *src_buf, size_t src_size
     } /* end if */
 
     /* Set output info */
-    H5MM_memcpy(dst_ref, &tmp_ref, sizeof(tmp_ref));
+    H5MM_memcpy(dst_buf, &tmp_ref, sizeof(tmp_ref));
 
 done:
     if ((file_id != H5I_INVALID_HID) && (H5I_dec_ref(file_id) < 0))
diff --git a/src/H5VLint.c b/src/H5VLint.c
index 477f5bc319a..cf65a7ff0ad 100644
--- a/src/H5VLint.c
+++ b/src/H5VLint.c
@@ -97,7 +97,7 @@ static void             *H5VL__wrap_obj(void *obj, H5I_type_t obj_type);
 static H5VL_connector_t *H5VL__conn_create(H5VL_class_t *cls);
 static herr_t            H5VL__conn_find(H5PL_vol_key_t *key, H5VL_connector_t **connector);
 static herr_t            H5VL__conn_free(H5VL_connector_t *connector);
-static herr_t            H5VL__conn_free_id(H5VL_connector_t *connector, void H5_ATTR_UNUSED **request);
+static herr_t            H5VL__conn_free_id(void *connector, void H5_ATTR_UNUSED **request);
 static void             *H5VL__object(hid_t id, H5I_type_t obj_type);
 static herr_t            H5VL__free_vol_wrapper(H5VL_wrap_ctx_t *vol_wrap_ctx);
 
@@ -118,10 +118,10 @@ bool H5_PKG_INIT_VAR = false;
 
 /* VOL ID class */
 static const H5I_class_t H5I_VOL_CLS[1] = {{
-    H5I_VOL,                       /* ID class value */
-    0,                             /* Class flags */
-    0,                             /* # of reserved IDs for class */
-    (H5I_free_t)H5VL__conn_free_id /* Callback routine for closing objects of this class */
+    H5I_VOL,           /* ID class value */
+    0,                 /* Class flags */
+    0,                 /* # of reserved IDs for class */
+    H5VL__conn_free_id /* Callback routine for closing objects of this class */
 }};
 
 /* Declare a free list to manage the H5VL_class_t struct */
@@ -1122,17 +1122,18 @@ H5VL__conn_free(H5VL_connector_t *connector)
  *-------------------------------------------------------------------------
  */
 static herr_t
-H5VL__conn_free_id(H5VL_connector_t *connector, void H5_ATTR_UNUSED **request)
+H5VL__conn_free_id(void *connector, void H5_ATTR_UNUSED **request)
 {
-    herr_t ret_value = SUCCEED; /* Return value */
+    H5VL_connector_t *connector_p = (H5VL_connector_t *)connector;
+    herr_t            ret_value   = SUCCEED; /* Return value */
 
     FUNC_ENTER_PACKAGE
 
     /* Check arguments */
-    assert(connector);
+    assert(connector_p);
 
     /* Decrement refcount on connector */
-    if (H5VL_conn_dec_rc(connector) < 0)
+    if (H5VL_conn_dec_rc(connector_p) < 0)
         HGOTO_ERROR(H5E_VOL, H5E_CANTDEC, FAIL, "unable to decrement ref count on VOL connector");
 
 done: