Cleanup: Continue renaming ARegion variables from ar to region

Continuation of b2ee1770d4c3, now non-single word variables are also
renamed.
Part of T74432.

Also ran clang-format on affected files.

33 files changed, 348 insertions, 344 deletions

diff --git a/source/blender/blenkernel/intern/screen.c b/source/blender/blenkernel/intern/screen.c
index dbf460fdea2..6c888e7b19e 100644
--- a/source/blender/blenkernel/intern/screen.c
+++ b/source/blender/blenkernel/intern/screen.c
@@ -748,19 +748,19 @@ ARegion *BKE_area_find_region_active_win(ScrArea *sa)
 
 ARegion *BKE_area_find_region_xy(ScrArea *sa, const int regiontype, int x, int y)
 {
-  ARegion *ar_found = NULL;
+  ARegion *region_found = NULL;
   if (sa) {
     ARegion *region;
     for (region = sa->regionbase.first; region; region = region->next) {
       if ((regiontype == RGN_TYPE_ANY) || (region->regiontype == regiontype)) {
         if (BLI_rcti_isect_pt(&region->winrct, x, y)) {
-          ar_found = region;
+          region_found = region;
           break;
         }
       }
     }
   }
-  return ar_found;
+  return region_found;
 }
 
 /**
@@ -768,16 +768,16 @@ ARegion *BKE_area_find_region_xy(ScrArea *sa, const int regiontype, int x, int y
  */
 ARegion *BKE_screen_find_region_xy(bScreen *sc, const int regiontype, int x, int y)
 {
-  ARegion *ar_found = NULL;
+  ARegion *region_found = NULL;
   for (ARegion *region = sc->regionbase.first; region; region = region->next) {
     if ((regiontype == RGN_TYPE_ANY) || (region->regiontype == regiontype)) {
       if (BLI_rcti_isect_pt(&region->winrct, x, y)) {
-        ar_found = region;
+        region_found = region;
         break;
       }
     }
   }
-  return ar_found;
+  return region_found;
 }
 
 /**
diff --git a/source/blender/blenloader/intern/versioning_250.c b/source/blender/blenloader/intern/versioning_250.c
index bb80aaaaa5a..68e654a8cd5 100644
--- a/source/blender/blenloader/intern/versioning_250.c
+++ b/source/blender/blenloader/intern/versioning_250.c
@@ -136,7 +136,7 @@ static void sequencer_init_preview_region(ARegion *region)
 static void area_add_window_regions(ScrArea *sa, SpaceLink *sl, ListBase *lb)
 {
   ARegion *region;
-  ARegion *ar_main;
+  ARegion *region_main;
 
   if (sl) {
     /* first channels for ipo action nla... */
@@ -205,14 +205,14 @@ static void area_add_window_regions(ScrArea *sa, SpaceLink *sl, ListBase *lb)
         region->alignment = RGN_ALIGN_TOP;
         break;
       case SPACE_SEQ:
-        ar_main = (ARegion *)lb->first;
-        for (; ar_main; ar_main = ar_main->next) {
-          if (ar_main->regiontype == RGN_TYPE_WINDOW) {
+        region_main = (ARegion *)lb->first;
+        for (; region_main; region_main = region_main->next) {
+          if (region_main->regiontype == RGN_TYPE_WINDOW) {
             break;
           }
         }
         region = MEM_callocN(sizeof(ARegion), "preview area for sequencer");
-        BLI_insertlinkbefore(lb, ar_main, region);
+        BLI_insertlinkbefore(lb, region_main, region);
         sequencer_init_preview_region(region);
         break;
       case SPACE_VIEW3D:
@@ -1235,7 +1235,7 @@ void blo_do_versions_250(FileData *fd, Library *lib, Main *bmain)
           for (sl = sa->spacedata.first; sl; sl = sl->next) {
             if (sl->spacetype == SPACE_SEQ) {
               ARegion *region;
-              ARegion *ar_main;
+              ARegion *region_main;
               ListBase *regionbase;
               SpaceSeq *sseq = (SpaceSeq *)sl;
 
@@ -1253,14 +1253,14 @@ void blo_do_versions_250(FileData *fd, Library *lib, Main *bmain)
                 sseq->mainb = SEQ_DRAW_IMG_IMBUF;
               }
 
-              ar_main = (ARegion *)regionbase->first;
-              for (; ar_main; ar_main = ar_main->next) {
-                if (ar_main->regiontype == RGN_TYPE_WINDOW) {
+              region_main = (ARegion *)regionbase->first;
+              for (; region_main; region_main = region_main->next) {
+                if (region_main->regiontype == RGN_TYPE_WINDOW) {
                   break;
                 }
               }
               region = MEM_callocN(sizeof(ARegion), "preview area for sequencer");
-              BLI_insertlinkbefore(regionbase, ar_main, region);
+              BLI_insertlinkbefore(regionbase, region_main, region);
               sequencer_init_preview_region(region);
             }
           }
@@ -1433,7 +1433,7 @@ void blo_do_versions_250(FileData *fd, Library *lib, Main *bmain)
         for (sa = screen->areabase.first; sa; sa = sa->next) {
           for (sl = sa->spacedata.first; sl; sl = sl->next) {
             if (sl->spacetype == SPACE_SEQ) {
-              ARegion *ar_preview;
+              ARegion *region_preview;
               ListBase *regionbase;
 
               if (sl == sa->spacedata.first) {
@@ -1443,14 +1443,14 @@ void blo_do_versions_250(FileData *fd, Library *lib, Main *bmain)
                 regionbase = &sl->regionbase;
               }
 
-              ar_preview = (ARegion *)regionbase->first;
-              for (; ar_preview; ar_preview = ar_preview->next) {
-                if (ar_preview->regiontype == RGN_TYPE_PREVIEW) {
+              region_preview = (ARegion *)regionbase->first;
+              for (; region_preview; region_preview = region_preview->next) {
+                if (region_preview->regiontype == RGN_TYPE_PREVIEW) {
                   break;
                 }
               }
-              if (ar_preview && (ar_preview->regiontype == RGN_TYPE_PREVIEW)) {
-                sequencer_init_preview_region(ar_preview);
+              if (region_preview && (region_preview->regiontype == RGN_TYPE_PREVIEW)) {
+                sequencer_init_preview_region(region_preview);
               }
             }
           }
diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index b3c0473e173..ac0c0c3da39 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -609,9 +609,9 @@ static void do_versions_remove_region(ListBase *regionbase, ARegion *region)
 
 static void do_versions_remove_regions_by_type(ListBase *regionbase, int regiontype)
 {
-  ARegion *region, *ar_next;
-  for (region = regionbase->first; region; region = ar_next) {
-    ar_next = region->next;
+  ARegion *region, *region_next;
+  for (region = regionbase->first; region; region = region_next) {
+    region_next = region->next;
     if (region->regiontype == regiontype) {
       do_versions_remove_region(regionbase, region);
     }
@@ -2934,9 +2934,9 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
         for (ScrArea *sa = screen->areabase.first; sa; sa = sa->next) {
           for (SpaceLink *sl = sa->spacedata.first; sl; sl = sl->next) {
             ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
-            ARegion *ar_header = do_versions_find_region_or_null(regionbase, RGN_TYPE_HEADER);
+            ARegion *region_header = do_versions_find_region_or_null(regionbase, RGN_TYPE_HEADER);
 
-            if (!ar_header) {
+            if (!region_header) {
               /* Headers should always be first in the region list, except if there's also a
                * tool-header. These were only introduced in later versions though, so should be
                * fine to always insert headers first. */
@@ -2959,16 +2959,17 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
           if (sl->spacetype == SPACE_PROPERTIES) {
             ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
             ARegion *region = MEM_callocN(sizeof(ARegion), "navigation bar for properties");
-            ARegion *ar_header = NULL;
+            ARegion *region_header = NULL;
 
-            for (ar_header = regionbase->first; ar_header; ar_header = ar_header->next) {
-              if (ar_header->regiontype == RGN_TYPE_HEADER) {
+            for (region_header = regionbase->first; region_header;
+                 region_header = region_header->next) {
+              if (region_header->regiontype == RGN_TYPE_HEADER) {
                 break;
               }
             }
-            BLI_assert(ar_header);
+            BLI_assert(region_header);
 
-            BLI_insertlinkafter(regionbase, ar_header, region);
+            BLI_insertlinkafter(regionbase, region_header, region);
 
             region->regiontype = RGN_TYPE_NAV_BAR;
             region->alignment = RGN_ALIGN_LEFT;
@@ -3468,13 +3469,13 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
             if (!execute_region) {
               ListBase *regionbase = (sl == area->spacedata.first) ? &area->regionbase :
                                                                      &sl->regionbase;
-              ARegion *ar_navbar = BKE_spacedata_find_region_type(sl, area, RGN_TYPE_NAV_BAR);
+              ARegion *region_navbar = BKE_spacedata_find_region_type(sl, area, RGN_TYPE_NAV_BAR);
 
               execute_region = MEM_callocN(sizeof(ARegion), "execute region for properties");
 
-              BLI_assert(ar_navbar);
+              BLI_assert(region_navbar);
 
-              BLI_insertlinkafter(regionbase, ar_navbar, execute_region);
+              BLI_insertlinkafter(regionbase, region_navbar, execute_region);
 
               execute_region->regiontype = RGN_TYPE_EXECUTE;
               execute_region->alignment = RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV;
@@ -3711,8 +3712,8 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
             ARegion *region = do_versions_add_region(RGN_TYPE_FOOTER, "footer for text");
             region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_TOP : RGN_ALIGN_BOTTOM;
 
-            ARegion *ar_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
-            BLI_insertlinkafter(regionbase, ar_header, region);
+            ARegion *region_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
+            BLI_insertlinkafter(regionbase, region_header, region);
           }
         }
       }
@@ -3804,8 +3805,8 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
             region = do_versions_add_region(RGN_TYPE_TOOL_HEADER, "tool header");
             region->alignment = (U.uiflag & USER_HEADER_BOTTOM) ? RGN_ALIGN_BOTTOM : RGN_ALIGN_TOP;
 
-            ARegion *ar_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
-            BLI_insertlinkbefore(regionbase, ar_header, region);
+            ARegion *region_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
+            BLI_insertlinkbefore(regionbase, region_header, region);
             /* Hide by default, enable for painting workspaces (startup only). */
             region->flag |= RGN_FLAG_HIDDEN | RGN_FLAG_HIDDEN_BY_USER;
           }
@@ -4136,24 +4137,25 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
           if (sl->spacetype == SPACE_FILE) {
             SpaceFile *sfile = (SpaceFile *)sl;
             ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
-            ARegion *ar_ui = do_versions_find_region(regionbase, RGN_TYPE_UI);
-            ARegion *ar_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
-            ARegion *ar_toolprops = do_versions_find_region_or_null(regionbase,
-                                                                    RGN_TYPE_TOOL_PROPS);
+            ARegion *region_ui = do_versions_find_region(regionbase, RGN_TYPE_UI);
+            ARegion *region_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
+            ARegion *region_toolprops = do_versions_find_region_or_null(regionbase,
+                                                                        RGN_TYPE_TOOL_PROPS);
 
             /* Reinsert UI region so that it spawns entire area width */
-            BLI_remlink(regionbase, ar_ui);
-            BLI_insertlinkafter(regionbase, ar_header, ar_ui);
+            BLI_remlink(regionbase, region_ui);
+            BLI_insertlinkafter(regionbase, region_header, region_ui);
 
-            ar_ui->flag |= RGN_FLAG_DYNAMIC_SIZE;
+            region_ui->flag |= RGN_FLAG_DYNAMIC_SIZE;
 
-            if (ar_toolprops && (ar_toolprops->alignment == (RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV))) {
+            if (region_toolprops &&
+                (region_toolprops->alignment == (RGN_ALIGN_BOTTOM | RGN_SPLIT_PREV))) {
               SpaceType *stype = BKE_spacetype_from_id(sl->spacetype);
 
               /* Remove empty region at old location. */
               BLI_assert(sfile->op == NULL);
-              BKE_area_region_free(stype, ar_toolprops);
-              BLI_freelinkN(regionbase, ar_toolprops);
+              BKE_area_region_free(stype, region_toolprops);
+              BLI_freelinkN(regionbase, region_toolprops);
             }
 
             if (sfile->params) {
@@ -4244,24 +4246,25 @@ void blo_do_versions_280(FileData *fd, Library *UNUSED(lib), Main *bmain)
           }
           else if (sl->spacetype == SPACE_FILE) {
             ListBase *regionbase = (sl == sa->spacedata.first) ? &sa->regionbase : &sl->regionbase;
-            ARegion *ar_tools = do_versions_find_region_or_null(regionbase, RGN_TYPE_TOOLS);
-            ARegion *ar_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
+            ARegion *region_tools = do_versions_find_region_or_null(regionbase, RGN_TYPE_TOOLS);
+            ARegion *region_header = do_versions_find_region(regionbase, RGN_TYPE_HEADER);
 
-            if (ar_tools) {
-              ARegion *ar_next = ar_tools->next;
+            if (region_tools) {
+              ARegion *region_next = region_tools->next;
 
               /* We temporarily had two tools regions, get rid of the second one. */
-              if (ar_next && ar_next->regiontype == RGN_TYPE_TOOLS) {
-                do_versions_remove_region(regionbase, ar_next);
+              if (region_next && region_next->regiontype == RGN_TYPE_TOOLS) {
+                do_versions_remove_region(regionbase, region_next);
               }
 
-              BLI_remlink(regionbase, ar_tools);
-              BLI_insertlinkafter(regionbase, ar_header, ar_tools);
+              BLI_remlink(regionbase, region_tools);
+              BLI_insertlinkafter(regionbase, region_header, region_tools);
             }
             else {
-              ar_tools = do_versions_add_region(RGN_TYPE_TOOLS, "versioning file tools region");
-              BLI_insertlinkafter(regionbase, ar_header, ar_tools);
-              ar_tools->alignment = RGN_ALIGN_LEFT;
+              region_tools = do_versions_add_region(RGN_TYPE_TOOLS,
+                                                    "versioning file tools region");
+              BLI_insertlinkafter(regionbase, region_header, region_tools);
+              region_tools->alignment = RGN_ALIGN_LEFT;
             }
           }
         }
diff --git a/source/blender/editors/include/ED_screen.h b/source/blender/editors/include/ED_screen.h
index 0785b0e97f7..7430f491d91 100644
--- a/source/blender/editors/include/ED_screen.h
+++ b/source/blender/editors/include/ED_screen.h
@@ -184,7 +184,7 @@ void ED_area_tag_refresh(ScrArea *sa);
 void ED_area_do_refresh(struct bContext *C, ScrArea *sa);
 struct AZone *ED_area_azones_update(ScrArea *sa, const int mouse_xy[]);
 void ED_area_status_text(ScrArea *sa, const char *str);
-void ED_area_newspace(struct bContext *C, ScrArea *sa, int type, const bool skip_ar_exit);
+void ED_area_newspace(struct bContext *C, ScrArea *sa, int type, const bool skip_region_exit);
 void ED_area_prevspace(struct bContext *C, ScrArea *sa);
 void ED_area_swapspace(struct bContext *C, ScrArea *sa1, ScrArea *sa2);
 int ED_area_headersize(void);
@@ -442,7 +442,7 @@ bool ED_region_overlap_isect_xy_with_margin(const ARegion *region,
                                             const int event_xy[2],
                                             const int margin);
 
-bool ED_region_panel_category_gutter_calc_rect(const ARegion *region, rcti *r_ar_gutter);
+bool ED_region_panel_category_gutter_calc_rect(const ARegion *region, rcti *r_region_gutter);
 bool ED_region_panel_category_gutter_isect_xy(const ARegion *region, const int event_xy[2]);
 
 bool ED_region_contains_xy(const struct ARegion *region, const int event_xy[2]);
diff --git a/source/blender/editors/include/ED_view3d.h b/source/blender/editors/include/ED_view3d.h
index bb065ee0008..86ad35cfa9f 100644
--- a/source/blender/editors/include/ED_view3d.h
+++ b/source/blender/editors/include/ED_view3d.h
@@ -560,10 +560,10 @@ bool edge_inside_circle(const float cent[2],
 struct RegionView3D *ED_view3d_context_rv3d(struct bContext *C);
 bool ED_view3d_context_user_region(struct bContext *C,
                                    struct View3D **r_v3d,
-                                   struct ARegion **r_ar);
+                                   struct ARegion **r_region);
 bool ED_view3d_area_user_region(const struct ScrArea *sa,
                                 const struct View3D *v3d,
-                                struct ARegion **r_ar);
+                                struct ARegion **r_region);
 bool ED_operator_rv3d_user_region_poll(struct bContext *C);
 
 void ED_view3d_init_mats_rv3d(struct Object *ob, struct RegionView3D *rv3d);
diff --git a/source/blender/editors/interface/interface_eyedropper_datablock.c b/source/blender/editors/interface/interface_eyedropper_datablock.c
index 93599b8727a..bf118481be2 100644
--- a/source/blender/editors/interface/interface_eyedropper_datablock.c
+++ b/source/blender/editors/interface/interface_eyedropper_datablock.c
@@ -155,7 +155,7 @@ static void datadropper_id_sample_pt(bContext *C, DataDropper *ddr, int mx, int
   ScrArea *sa = BKE_screen_find_area_xy(screen, -1, mx, my);
 
   ScrArea *area_prev = CTX_wm_area(C);
-  ARegion *ar_prev = CTX_wm_region(C);
+  ARegion *region_prev = CTX_wm_region(C);
 
   ddr->name[0] = '\0';
 
@@ -208,7 +208,7 @@ static void datadropper_id_sample_pt(bContext *C, DataDropper *ddr, int mx, int
   }
 
   CTX_wm_area_set(C, area_prev);
-  CTX_wm_region_set(C, ar_prev);
+  CTX_wm_region_set(C, region_prev);
 }
 
 /* sets the ID, returns success */
diff --git a/source/blender/editors/interface/interface_eyedropper_depth.c b/source/blender/editors/interface/interface_eyedropper_depth.c
index a5e60adec55..26a6109e8cf 100644
--- a/source/blender/editors/interface/interface_eyedropper_depth.c
+++ b/source/blender/editors/interface/interface_eyedropper_depth.c
@@ -160,7 +160,7 @@ static void depthdropper_depth_sample_pt(
   Scene *scene = CTX_data_scene(C);
 
   ScrArea *area_prev = CTX_wm_area(C);
-  ARegion *ar_prev = CTX_wm_region(C);
+  ARegion *region_prev = CTX_wm_region(C);
 
   ddr->name[0] = '\0';
 
@@ -209,7 +209,7 @@ static void depthdropper_depth_sample_pt(
   }
 
   CTX_wm_area_set(C, area_prev);
-  CTX_wm_region_set(C, ar_prev);
+  CTX_wm_region_set(C, region_prev);
 }
 
 /* sets the sample depth RGB, maintaining A */
diff --git a/source/blender/editors/interface/interface_handlers.c b/source/blender/editors/interface/interface_handlers.c
index d378613c035..61c59643bcd 100644
--- a/source/blender/editors/interface/interface_handlers.c
+++ b/source/blender/editors/interface/interface_handlers.c
@@ -1874,7 +1874,7 @@ static bool ui_but_drag_init(bContext *C,
 #ifdef USE_DRAG_TOGGLE
     if (ui_drag_toggle_but_is_supported(but)) {
       uiDragToggleHandle *drag_info = MEM_callocN(sizeof(*drag_info), __func__);
-      ARegion *ar_prev;
+      ARegion *region_prev;
 
       /* call here because regular mouse-up event wont run,
        * typically 'button_activate_exit()' handles this */
@@ -1887,7 +1887,7 @@ static bool ui_but_drag_init(bContext *C,
       copy_v2_v2_int(drag_info->xy_last, &event->x);
 
       /* needed for toggle drag on popups */
-      ar_prev = CTX_wm_region(C);
+      region_prev = CTX_wm_region(C);
       CTX_wm_region_set(C, data->region);
 
       WM_event_add_ui_handler(C,
@@ -1897,7 +1897,7 @@ static bool ui_but_drag_init(bContext *C,
                               drag_info,
                               WM_HANDLER_BLOCKING);
 
-      CTX_wm_region_set(C, ar_prev);
+      CTX_wm_region_set(C, region_prev);
 
       /* Initialize alignment for single row/column regions,
        * otherwise we use the relative position of the first other button dragged over. */
@@ -1906,13 +1906,13 @@ static bool ui_but_drag_init(bContext *C,
                RGN_TYPE_HEADER,
                RGN_TYPE_TOOL_HEADER,
                RGN_TYPE_FOOTER)) {
-        const int ar_alignment = RGN_ALIGN_ENUM_FROM_MASK(data->region->alignment);
+        const int region_alignment = RGN_ALIGN_ENUM_FROM_MASK(data->region->alignment);
         int lock_axis = -1;
 
-        if (ELEM(ar_alignment, RGN_ALIGN_LEFT, RGN_ALIGN_RIGHT)) {
+        if (ELEM(region_alignment, RGN_ALIGN_LEFT, RGN_ALIGN_RIGHT)) {
           lock_axis = 0;
         }
-        else if (ELEM(ar_alignment, RGN_ALIGN_TOP, RGN_ALIGN_BOTTOM)) {
+        else if (ELEM(region_alignment, RGN_ALIGN_TOP, RGN_ALIGN_BOTTOM)) {
           lock_axis = 1;
         }
         if (lock_axis != -1) {
@@ -8326,16 +8326,16 @@ void UI_context_active_but_prop_handle(bContext *C)
 
 wmOperator *UI_context_active_operator_get(const struct bContext *C)
 {
-  ARegion *ar_ctx = CTX_wm_region(C);
+  ARegion *region_ctx = CTX_wm_region(C);
   uiBlock *block;
 
   /* background mode */
-  if (ar_ctx == NULL) {
+  if (region_ctx == NULL) {
     return NULL;
   }
 
   /* scan active regions ui */
-  for (block = ar_ctx->uiblocks.first; block; block = block->next) {
+  for (block = region_ctx->uiblocks.first; block; block = block->next) {
     if (block->ui_operator) {
       return block->ui_operator;
     }
@@ -8347,7 +8347,7 @@ wmOperator *UI_context_active_operator_get(const struct bContext *C)
     ARegion *region;
 
     for (region = sc->regionbase.first; region; region = region->next) {
-      if (region == ar_ctx) {
+      if (region == region_ctx) {
         continue;
       }
       for (block = region->uiblocks.first; block; block = block->next) {
@@ -8470,10 +8470,10 @@ void ui_but_activate_event(bContext *C, ARegion *region, uiBut *but)
   event.customdata = but;
   event.customdatafree = false;
 
-  ARegion *ar_ctx = CTX_wm_region(C);
+  ARegion *region_ctx = CTX_wm_region(C);
   CTX_wm_region_set(C, region);
   ui_do_button(C, but->block, but, &event);
-  CTX_wm_region_set(C, ar_ctx);
+  CTX_wm_region_set(C, region_ctx);
 }
 
 /**
diff --git a/source/blender/editors/interface/interface_ops.c b/source/blender/editors/interface/interface_ops.c
index b418cb4a1ac..5a4a549ea3e 100644
--- a/source/blender/editors/interface/interface_ops.c
+++ b/source/blender/editors/interface/interface_ops.c
@@ -1622,11 +1622,11 @@ static int ui_button_press_invoke(bContext *C, wmOperator *op, const wmEvent *ev
 {
   bScreen *sc = CTX_wm_screen(C);
   const bool skip_depressed = RNA_boolean_get(op->ptr, "skip_depressed");
-  ARegion *ar_prev = CTX_wm_region(C);
+  ARegion *region_prev = CTX_wm_region(C);
   ARegion *region = sc ? BKE_screen_find_region_xy(sc, RGN_TYPE_ANY, event->x, event->y) : NULL;
 
   if (region == NULL) {
-    region = ar_prev;
+    region = region_prev;
   }
 
   if (region == NULL) {
@@ -1635,7 +1635,7 @@ static int ui_button_press_invoke(bContext *C, wmOperator *op, const wmEvent *ev
 
   CTX_wm_region_set(C, region);
   uiBut *but = UI_context_active_but_get(C);
-  CTX_wm_region_set(C, ar_prev);
+  CTX_wm_region_set(C, region_prev);
 
   if (but == NULL) {
     return OPERATOR_PASS_THROUGH;
diff --git a/source/blender/editors/interface/interface_region_hud.c b/source/blender/editors/interface/interface_region_hud.c
index f77739b5114..e0fc7a3ee71 100644
--- a/source/blender/editors/interface/interface_region_hud.c
+++ b/source/blender/editors/interface/interface_region_hud.c
@@ -75,14 +75,14 @@ static bool last_redo_poll(const bContext *C, short region_type)
      * wrong context.
      */
     ScrArea *sa = CTX_wm_area(C);
-    ARegion *ar_op = (region_type != -1) ? BKE_area_find_region_type(sa, region_type) : NULL;
-    ARegion *ar_prev = CTX_wm_region(C);
-    CTX_wm_region_set((bContext *)C, ar_op);
+    ARegion *region_op = (region_type != -1) ? BKE_area_find_region_type(sa, region_type) : NULL;
+    ARegion *region_prev = CTX_wm_region(C);
+    CTX_wm_region_set((bContext *)C, region_op);
 
     if (WM_operator_repeat_check(C, op) && WM_operator_check_ui_empty(op->type) == false) {
       success = WM_operator_poll((bContext *)C, op->type);
     }
-    CTX_wm_region_set((bContext *)C, ar_prev);
+    CTX_wm_region_set((bContext *)C, region_prev);
   }
   return success;
 }
@@ -253,9 +253,9 @@ ARegionType *ED_area_type_hud(int space_type)
 static ARegion *hud_region_add(ScrArea *sa)
 {
   ARegion *region = MEM_callocN(sizeof(ARegion), "area region");
-  ARegion *ar_win = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
-  if (ar_win) {
-    BLI_insertlinkbefore(&sa->regionbase, ar_win, region);
+  ARegion *region_win = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
+  if (region_win) {
+    BLI_insertlinkbefore(&sa->regionbase, region_win, region);
   }
   else {
     BLI_addtail(&sa->regionbase, region);
@@ -265,10 +265,10 @@ static ARegion *hud_region_add(ScrArea *sa)
   region->overlap = true;
   region->flag |= RGN_FLAG_DYNAMIC_SIZE;
 
-  if (ar_win) {
+  if (region_win) {
     float x, y;
 
-    UI_view2d_scroller_size_get(&ar_win->v2d, &x, &y);
+    UI_view2d_scroller_size_get(&region_win->v2d, &x, &y);
     region->runtime.offset_x = x;
     region->runtime.offset_y = y;
   }
@@ -316,9 +316,9 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *sa)
 
   bool init = false;
   bool was_hidden = region == NULL || region->visible == false;
-  ARegion *ar_op = CTX_wm_region(C);
-  BLI_assert((ar_op == NULL) || (ar_op->regiontype != RGN_TYPE_HUD));
-  if (!last_redo_poll(C, ar_op ? ar_op->regiontype : -1)) {
+  ARegion *region_op = CTX_wm_region(C);
+  BLI_assert((region_op == NULL) || (region_op->regiontype != RGN_TYPE_HUD));
+  if (!last_redo_poll(C, region_op ? region_op->regiontype : -1)) {
     if (region) {
       ED_region_tag_redraw(region);
       hud_region_hide(region);
@@ -350,8 +350,8 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *sa)
       hrd = MEM_callocN(sizeof(*hrd), __func__);
       region->regiondata = hrd;
     }
-    if (ar_op) {
-      hrd->regionid = ar_op->regiontype;
+    if (region_op) {
+      hrd->regionid = region_op->regiontype;
     }
     else {
       hrd->regionid = -1;
@@ -380,7 +380,7 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *sa)
   /* We shouldn't need to do this every time :S */
   /* XXX, this is evil! - it also makes the menu show on first draw. :( */
   if (region->visible) {
-    ARegion *ar_prev = CTX_wm_region(C);
+    ARegion *region_prev = CTX_wm_region(C);
     CTX_wm_region_set((bContext *)C, region);
     hud_region_layout(C, region);
     if (was_hidden) {
@@ -391,7 +391,7 @@ void ED_area_type_hud_ensure(bContext *C, ScrArea *sa)
           .ymax = region->winy,
       };
     }
-    CTX_wm_region_set((bContext *)C, ar_prev);
+    CTX_wm_region_set((bContext *)C, region_prev);
   }
 
   region->visible = !((region->flag & RGN_FLAG_HIDDEN) || (region->flag & RGN_FLAG_TOO_SMALL));
diff --git a/source/blender/editors/interface/interface_region_popup.c b/source/blender/editors/interface/interface_region_popup.c
index ba9a5026ce3..7e32a91d08d 100644
--- a/source/blender/editors/interface/interface_region_popup.c
+++ b/source/blender/editors/interface/interface_region_popup.c
@@ -526,7 +526,7 @@ static void ui_popup_block_remove(bContext *C, uiPopupBlockHandle *handle)
 {
   wmWindow *ctx_win = CTX_wm_window(C);
   ScrArea *ctx_sa = CTX_wm_area(C);
-  ARegion *ctx_ar = CTX_wm_region(C);
+  ARegion *ctx_region = CTX_wm_region(C);
 
   wmWindowManager *wm = CTX_wm_manager(C);
   wmWindow *win = ctx_win;
@@ -551,7 +551,7 @@ static void ui_popup_block_remove(bContext *C, uiPopupBlockHandle *handle)
   /* Reset context (area and region were NULL'ed when chaning context window). */
   CTX_wm_window_set(C, ctx_win);
   CTX_wm_area_set(C, ctx_sa);
-  CTX_wm_region_set(C, ctx_ar);
+  CTX_wm_region_set(C, ctx_region);
 
   /* reset to region cursor (only if there's not another menu open) */
   if (BLI_listbase_is_empty(&sc->regionbase)) {
diff --git a/source/blender/editors/screen/area.c b/source/blender/editors/screen/area.c
index 56ea59c1d6e..efa98c358df 100644
--- a/source/blender/editors/screen/area.c
+++ b/source/blender/editors/screen/area.c
@@ -2076,9 +2076,9 @@ void ED_area_swapspace(bContext *C, ScrArea *sa1, ScrArea *sa2)
 }
 
 /**
- * \param skip_ar_exit: Skip calling area exit callback. Set for opening temp spaces.
+ * \param skip_region_exit: Skip calling area exit callback. Set for opening temp spaces.
  */
-void ED_area_newspace(bContext *C, ScrArea *sa, int type, const bool skip_ar_exit)
+void ED_area_newspace(bContext *C, ScrArea *sa, int type, const bool skip_region_exit)
 {
   wmWindow *win = CTX_wm_window(C);
 
@@ -2104,14 +2104,14 @@ void ED_area_newspace(bContext *C, ScrArea *sa, int type, const bool skip_ar_exi
 
     /* in some cases (opening temp space) we don't want to
      * call area exit callback, so we temporarily unset it */
-    if (skip_ar_exit && sa->type) {
+    if (skip_region_exit && sa->type) {
       sa->type->exit = NULL;
     }
 
     ED_area_exit(C, sa);
 
     /* restore old area exit callback */
-    if (skip_ar_exit && sa->type) {
+    if (skip_region_exit && sa->type) {
       sa->type->exit = sa_exit;
     }
 
diff --git a/source/blender/editors/screen/area_query.c b/source/blender/editors/screen/area_query.c
index 739f1b93e07..d569e56e11b 100644
--- a/source/blender/editors/screen/area_query.c
+++ b/source/blender/editors/screen/area_query.c
@@ -73,19 +73,19 @@ bool ED_region_overlap_isect_any_xy(const ScrArea *area, const int event_xy[2])
   return false;
 }
 
-bool ED_region_panel_category_gutter_calc_rect(const ARegion *region, rcti *r_ar_gutter)
+bool ED_region_panel_category_gutter_calc_rect(const ARegion *region, rcti *r_region_gutter)
 {
-  *r_ar_gutter = region->winrct;
+  *r_region_gutter = region->winrct;
   if (UI_panel_category_is_visible(region)) {
     const int category_tabs_width = round_fl_to_int(UI_view2d_scale_get_x(&region->v2d) *
                                                     UI_PANEL_CATEGORY_MARGIN_WIDTH);
     const int alignment = RGN_ALIGN_ENUM_FROM_MASK(region->alignment);
 
     if (alignment == RGN_ALIGN_LEFT) {
-      r_ar_gutter->xmax = r_ar_gutter->xmin + category_tabs_width;
+      r_region_gutter->xmax = r_region_gutter->xmin + category_tabs_width;
     }
     else if (alignment == RGN_ALIGN_RIGHT) {
-      r_ar_gutter->xmin = r_ar_gutter->xmax - category_tabs_width;
+      r_region_gutter->xmin = r_region_gutter->xmax - category_tabs_width;
     }
     else {
       BLI_assert(!"Unsupported alignment");
@@ -97,9 +97,9 @@ bool ED_region_panel_category_gutter_calc_rect(const ARegion *region, rcti *r_ar
 
 bool ED_region_panel_category_gutter_isect_xy(const ARegion *region, const int event_xy[2])
 {
-  rcti ar_gutter;
-  if (ED_region_panel_category_gutter_calc_rect(region, &ar_gutter)) {
-    return BLI_rcti_isect_pt_v(&ar_gutter, event_xy);
+  rcti region_gutter;
+  if (ED_region_panel_category_gutter_calc_rect(region, &region_gutter)) {
+    return BLI_rcti_isect_pt_v(&region_gutter, event_xy);
   }
   return false;
 }
diff --git a/source/blender/editors/screen/screen_edit.c b/source/blender/editors/screen/screen_edit.c
index 0151a0fcb0d..01a30f7d6a4 100644
--- a/source/blender/editors/screen/screen_edit.c
+++ b/source/blender/editors/screen/screen_edit.c
@@ -687,7 +687,7 @@ void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
 
   ScrArea *sa = NULL;
   ARegion *region;
-  ARegion *ar_prev = scr->active_region;
+  ARegion *region_prev = scr->active_region;
 
   ED_screen_areas_iter(win, scr, area_iter)
   {
@@ -714,7 +714,7 @@ void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
   }
 
   /* Check for redraw headers. */
-  if (ar_prev != scr->active_region) {
+  if (region_prev != scr->active_region) {
 
     ED_screen_areas_iter(win, scr, area_iter)
     {
@@ -723,20 +723,20 @@ void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
       for (region = area_iter->regionbase.first; region; region = region->next) {
 
         /* Call old area's deactivate if assigned. */
-        if (region == ar_prev && area_iter->type->deactivate) {
+        if (region == region_prev && area_iter->type->deactivate) {
           area_iter->type->deactivate(area_iter);
         }
 
-        if (region == ar_prev && region != scr->active_region) {
-          wmGizmoMap *gzmap = ar_prev->gizmo_map;
+        if (region == region_prev && region != scr->active_region) {
+          wmGizmoMap *gzmap = region_prev->gizmo_map;
           if (gzmap) {
             if (WM_gizmo_highlight_set(gzmap, NULL)) {
-              ED_region_tag_redraw_no_rebuild(ar_prev);
+              ED_region_tag_redraw_no_rebuild(region_prev);
             }
           }
         }
 
-        if (region == ar_prev || region == scr->active_region) {
+        if (region == region_prev || region == scr->active_region) {
           do_draw = true;
         }
       }
@@ -758,9 +758,9 @@ void ED_screen_set_active_region(bContext *C, wmWindow *win, const int xy[2])
   }
   else {
     /* Notifier invokes freeing the buttons... causing a bit too much redraws. */
-    region_cursor_set_ex(win, sa, scr->active_region, ar_prev != scr->active_region);
+    region_cursor_set_ex(win, sa, scr->active_region, region_prev != scr->active_region);
 
-    if (ar_prev != scr->active_region) {
+    if (region_prev != scr->active_region) {
       /* This used to be a notifier, but needs to be done immediate
        * because it can undo setting the right button as active due
        * to delayed notifier handling. */
diff --git a/source/blender/editors/screen/screen_ops.c b/source/blender/editors/screen/screen_ops.c
index ae8dd829d8d..5eb676cd25c 100644
--- a/source/blender/editors/screen/screen_ops.c
+++ b/source/blender/editors/screen/screen_ops.c
@@ -2641,11 +2641,11 @@ static void region_scale_toggle_hidden(bContext *C, RegionMoveData *rmd)
 
   if ((rmd->region->flag & RGN_FLAG_HIDDEN) == 0) {
     if (rmd->region->regiontype == RGN_TYPE_HEADER) {
-      ARegion *ar_tool_header = BKE_area_find_region_type(rmd->sa, RGN_TYPE_TOOL_HEADER);
-      if (ar_tool_header != NULL) {
-        if ((ar_tool_header->flag & RGN_FLAG_HIDDEN_BY_USER) == 0 &&
-            (ar_tool_header->flag & RGN_FLAG_HIDDEN) != 0) {
-          region_toggle_hidden(C, ar_tool_header, 0);
+      ARegion *region_tool_header = BKE_area_find_region_type(rmd->sa, RGN_TYPE_TOOL_HEADER);
+      if (region_tool_header != NULL) {
+        if ((region_tool_header->flag & RGN_FLAG_HIDDEN_BY_USER) == 0 &&
+            (region_tool_header->flag & RGN_FLAG_HIDDEN) != 0) {
+          region_toggle_hidden(C, region_tool_header, 0);
         }
       }
     }
@@ -3848,17 +3848,17 @@ static int region_quadview_exec(bContext *C, wmOperator *op)
     region->alignment = 0;
 
     if (sa->spacetype == SPACE_VIEW3D) {
-      ARegion *ar_iter;
+      ARegion *region_iter;
       RegionView3D *rv3d = region->regiondata;
 
       /* if this is a locked view, use settings from 'User' view */
       if (rv3d->viewlock) {
         View3D *v3d_user;
-        ARegion *ar_user;
+        ARegion *region_user;
 
-        if (ED_view3d_context_user_region(C, &v3d_user, &ar_user)) {
-          if (region != ar_user) {
-            SWAP(void *, region->regiondata, ar_user->regiondata);
+        if (ED_view3d_context_user_region(C, &v3d_user, &region_user)) {
+          if (region != region_user) {
+            SWAP(void *, region->regiondata, region_user->regiondata);
             rv3d = region->regiondata;
           }
         }
@@ -3869,9 +3869,9 @@ static int region_quadview_exec(bContext *C, wmOperator *op)
       rv3d->rflag &= ~RV3D_CLIPPING;
 
       /* Accumulate locks, in case they're mixed. */
-      for (ar_iter = sa->regionbase.first; ar_iter; ar_iter = ar_iter->next) {
-        if (ar_iter->regiontype == RGN_TYPE_WINDOW) {
-          RegionView3D *rv3d_iter = ar_iter->regiondata;
+      for (region_iter = sa->regionbase.first; region_iter; region_iter = region_iter->next) {
+        if (region_iter->regiontype == RGN_TYPE_WINDOW) {
+          RegionView3D *rv3d_iter = region_iter->regiondata;
           rv3d->viewlock_quad |= rv3d_iter->viewlock;
         }
       }
@@ -4140,9 +4140,9 @@ void ED_screens_header_tools_menu_create(bContext *C, uiLayout *layout, void *UN
       uiItemR(layout, &ptr, "show_region_header", 0, IFACE_("Show Header"), ICON_NONE);
     }
 
-    ARegion *ar_header = BKE_area_find_region_type(sa, RGN_TYPE_HEADER);
+    ARegion *region_header = BKE_area_find_region_type(sa, RGN_TYPE_HEADER);
     uiLayout *col = uiLayoutColumn(layout, 0);
-    uiLayoutSetActive(col, (ar_header->flag & RGN_FLAG_HIDDEN) == 0);
+    uiLayoutSetActive(col, (region_header->flag & RGN_FLAG_HIDDEN) == 0);
 
     if (BKE_area_find_region_type(sa, RGN_TYPE_TOOL_HEADER)) {
       uiItemR(col, &ptr, "show_region_tool_header", 0, IFACE_("Show Tool Settings"), ICON_NONE);
@@ -5070,7 +5070,7 @@ static void SCREEN_OT_delete(wmOperatorType *ot)
 
 typedef struct RegionAlphaInfo {
   ScrArea *sa;
-  ARegion *region, *child_ar; /* other region */
+  ARegion *region, *child_region; /* other region */
   int hidden;
 } RegionAlphaInfo;
 
@@ -5107,8 +5107,8 @@ static void region_blend_end(bContext *C, ARegion *region, const bool is_running
 
   /* always send redraw */
   ED_region_tag_redraw(region);
-  if (rgi->child_ar) {
-    ED_region_tag_redraw(rgi->child_ar);
+  if (rgi->child_region) {
+    ED_region_tag_redraw(rgi->child_region);
   }
 
   /* if running timer was hiding, the flag toggle went wrong */
@@ -5159,7 +5159,7 @@ void ED_region_visibility_change_update_animated(bContext *C, ScrArea *sa, ARegi
 
   if (region->next) {
     if (region->next->alignment & RGN_SPLIT_PREV) {
-      rgi->child_ar = region->next;
+      rgi->child_region = region->next;
     }
   }
 
@@ -5183,8 +5183,8 @@ static int region_blend_invoke(bContext *C, wmOperator *UNUSED(op), const wmEven
 
   /* always send redraws */
   ED_region_tag_redraw(rgi->region);
-  if (rgi->child_ar) {
-    ED_region_tag_redraw(rgi->child_ar);
+  if (rgi->child_region) {
+    ED_region_tag_redraw(rgi->child_region);
   }
 
   /* end timer? */
diff --git a/source/blender/editors/sculpt_paint/sculpt.c b/source/blender/editors/sculpt_paint/sculpt.c
index fede8ce97ca..8d4870f5dd8 100644
--- a/source/blender/editors/sculpt_paint/sculpt.c
+++ b/source/blender/editors/sculpt_paint/sculpt.c
@@ -9275,7 +9275,7 @@ static int sample_detail(bContext *C, int mx, int my, int mode)
 
   /* Set context to 3D view. */
   ScrArea *prev_sa = CTX_wm_area(C);
-  ARegion *prev_ar = CTX_wm_region(C);
+  ARegion *prev_region = CTX_wm_region(C);
   CTX_wm_area_set(C, sa);
   CTX_wm_region_set(C, region);
 
@@ -9295,7 +9295,7 @@ static int sample_detail(bContext *C, int mx, int my, int mode)
     case SAMPLE_DETAIL_DYNTOPO:
       if (BKE_pbvh_type(ss->pbvh) != PBVH_BMESH) {
         CTX_wm_area_set(C, prev_sa);
-        CTX_wm_region_set(C, prev_ar);
+        CTX_wm_region_set(C, prev_region);
         return OPERATOR_CANCELLED;
       }
       sample_detail_dyntopo(C, &vc, region, mx, my);
@@ -9303,7 +9303,7 @@ static int sample_detail(bContext *C, int mx, int my, int mode)
     case SAMPLE_DETAIL_VOXEL:
       if (BKE_pbvh_type(ss->pbvh) != PBVH_FACES) {
         CTX_wm_area_set(C, prev_sa);
-        CTX_wm_region_set(C, prev_ar);
+        CTX_wm_region_set(C, prev_region);
         return OPERATOR_CANCELLED;
       }
       sample_detail_voxel(C, &vc, mx, my);
@@ -9312,7 +9312,7 @@ static int sample_detail(bContext *C, int mx, int my, int mode)
 
   /* Restore context. */
   CTX_wm_area_set(C, prev_sa);
-  CTX_wm_region_set(C, prev_ar);
+  CTX_wm_region_set(C, prev_region);
 
   return OPERATOR_FINISHED;
 }
diff --git a/source/blender/editors/space_clip/space_clip.c b/source/blender/editors/space_clip/space_clip.c
index 4b9c872ffce..82fb429d36c 100644
--- a/source/blender/editors/space_clip/space_clip.c
+++ b/source/blender/editors/space_clip/space_clip.c
@@ -645,11 +645,11 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
   wmWindow *window = CTX_wm_window(C);
   Scene *scene = CTX_data_scene(C);
   SpaceClip *sc = (SpaceClip *)sa->spacedata.first;
-  ARegion *ar_main = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
-  ARegion *ar_tools = BKE_area_find_region_type(sa, RGN_TYPE_TOOLS);
-  ARegion *ar_preview = ED_clip_has_preview_region(C, sa);
-  ARegion *ar_properties = ED_clip_has_properties_region(sa);
-  ARegion *ar_channels = ED_clip_has_channels_region(sa);
+  ARegion *region_main = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
+  ARegion *region_tools = BKE_area_find_region_type(sa, RGN_TYPE_TOOLS);
+  ARegion *region_preview = ED_clip_has_preview_region(C, sa);
+  ARegion *region_properties = ED_clip_has_properties_region(sa);
+  ARegion *region_channels = ED_clip_has_channels_region(sa);
   bool main_visible = false, preview_visible = false, tools_visible = false;
   bool properties_visible = false, channels_visible = false;
   bool view_changed = false;
@@ -669,7 +669,7 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
       properties_visible = false;
       channels_visible = false;
 
-      reinit_preview_region(C, ar_preview);
+      reinit_preview_region(C, region_preview);
       break;
     case SC_VIEW_DOPESHEET:
       main_visible = false;
@@ -678,128 +678,128 @@ static void clip_refresh(const bContext *C, ScrArea *sa)
       properties_visible = false;
       channels_visible = true;
 
-      reinit_preview_region(C, ar_preview);
+      reinit_preview_region(C, region_preview);
       break;
   }
 
   if (main_visible) {
-    if (ar_main && (ar_main->flag & RGN_FLAG_HIDDEN)) {
-      ar_main->flag &= ~RGN_FLAG_HIDDEN;
-      ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
+    if (region_main && (region_main->flag & RGN_FLAG_HIDDEN)) {
+      region_main->flag &= ~RGN_FLAG_HIDDEN;
+      region_main->v2d.flag &= ~V2D_IS_INITIALISED;
       view_changed = true;
     }
 
-    if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
-      ar_main->alignment = RGN_ALIGN_NONE;
+    if (region_main && region_main->alignment != RGN_ALIGN_NONE) {
+      region_main->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
   else {
-    if (ar_main && !(ar_main->flag & RGN_FLAG_HIDDEN)) {
-      ar_main->flag |= RGN_FLAG_HIDDEN;
-      ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
-      WM_event_remove_handlers((bContext *)C, &ar_main->handlers);
+    if (region_main && !(region_main->flag & RGN_FLAG_HIDDEN)) {
+      region_main->flag |= RGN_FLAG_HIDDEN;
+      region_main->v2d.flag &= ~V2D_IS_INITIALISED;
+      WM_event_remove_handlers((bContext *)C, &region_main->handlers);
       view_changed = true;
     }
-    if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
-      ar_main->alignment = RGN_ALIGN_NONE;
+    if (region_main && region_main->alignment != RGN_ALIGN_NONE) {
+      region_main->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
 
   if (properties_visible) {
-    if (ar_properties && (ar_properties->flag & RGN_FLAG_HIDDEN)) {
-      ar_properties->flag &= ~RGN_FLAG_HIDDEN;
-      ar_properties->v2d.flag &= ~V2D_IS_INITIALISED;
+    if (region_properties && (region_properties->flag & RGN_FLAG_HIDDEN)) {
+      region_properties->flag &= ~RGN_FLAG_HIDDEN;
+      region_properties->v2d.flag &= ~V2D_IS_INITIALISED;
       view_changed = true;
     }
-    if (ar_properties && ar_properties->alignment != RGN_ALIGN_RIGHT) {
-      ar_properties->alignment = RGN_ALIGN_RIGHT;
+    if (region_properties && region_properties->alignment != RGN_ALIGN_RIGHT) {
+      region_properties->alignment = RGN_ALIGN_RIGHT;
       view_changed = true;
     }
   }
   else {
-    if (ar_properties && !(ar_properties->flag & RGN_FLAG_HIDDEN)) {
-      ar_properties->flag |= RGN_FLAG_HIDDEN;
-      ar_properties->v2d.flag &= ~V2D_IS_INITIALISED;
-      WM_event_remove_handlers((bContext *)C, &ar_properties->handlers);
+    if (region_properties && !(region_properties->flag & RGN_FLAG_HIDDEN)) {
+      region_properties->flag |= RGN_FLAG_HIDDEN;
+      region_properties->v2d.flag &= ~V2D_IS_INITIALISED;
+      WM_event_remove_handlers((bContext *)C, &region_properties->handlers);
       view_changed = true;
     }
-    if (ar_properties && ar_properties->alignment != RGN_ALIGN_NONE) {
-      ar_properties->alignment = RGN_ALIGN_NONE;
+    if (region_properties && region_properties->alignment != RGN_ALIGN_NONE) {
+      region_properties->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
 
   if (tools_visible) {
-    if (ar_tools && (ar_tools->flag & RGN_FLAG_HIDDEN)) {
-      ar_tools->flag &= ~RGN_FLAG_HIDDEN;
-      ar_tools->v2d.flag &= ~V2D_IS_INITIALISED;
+    if (region_tools && (region_tools->flag & RGN_FLAG_HIDDEN)) {
+      region_tools->flag &= ~RGN_FLAG_HIDDEN;
+      region_tools->v2d.flag &= ~V2D_IS_INITIALISED;
       view_changed = true;
     }
-    if (ar_tools && ar_tools->alignment != RGN_ALIGN_LEFT) {
-      ar_tools->alignment = RGN_ALIGN_LEFT;
+    if (region_tools && region_tools->alignment != RGN_ALIGN_LEFT) {
+      region_tools->alignment = RGN_ALIGN_LEFT;
       view_changed = true;
     }
   }
   else {
-    if (ar_tools && !(ar_tools->flag & RGN_FLAG_HIDDEN)) {
-      ar_tools->flag |= RGN_FLAG_HIDDEN;
-      ar_tools->v2d.flag &= ~V2D_IS_INITIALISED;
-      WM_event_remove_handlers((bContext *)C, &ar_tools->handlers);
+    if (region_tools && !(region_tools->flag & RGN_FLAG_HIDDEN)) {
+      region_tools->flag |= RGN_FLAG_HIDDEN;
+      region_tools->v2d.flag &= ~V2D_IS_INITIALISED;
+      WM_event_remove_handlers((bContext *)C, &region_tools->handlers);
       view_changed = true;
     }
-    if (ar_tools && ar_tools->alignment != RGN_ALIGN_NONE) {
-      ar_tools->alignment = RGN_ALIGN_NONE;
+    if (region_tools && region_tools->alignment != RGN_ALIGN_NONE) {
+      region_tools->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
 
   if (preview_visible) {
-    if (ar_preview && (ar_preview->flag & RGN_FLAG_HIDDEN)) {
-      ar_preview->flag &= ~RGN_FLAG_HIDDEN;
-      ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
-      ar_preview->v2d.cur = ar_preview->v2d.tot;
+    if (region_preview && (region_preview->flag & RGN_FLAG_HIDDEN)) {
+      region_preview->flag &= ~RGN_FLAG_HIDDEN;
+      region_preview->v2d.flag &= ~V2D_IS_INITIALISED;
+      region_preview->v2d.cur = region_preview->v2d.tot;
       view_changed = true;
     }
-    if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
-      ar_preview->alignment = RGN_ALIGN_NONE;
+    if (region_preview && region_preview->alignment != RGN_ALIGN_NONE) {
+      region_preview->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
   else {
-    if (ar_preview && !(ar_preview->flag & RGN_FLAG_HIDDEN)) {
-      ar_preview->flag |= RGN_FLAG_HIDDEN;
-      ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
-      WM_event_remove_handlers((bContext *)C, &ar_preview->handlers);
+    if (region_preview && !(region_preview->flag & RGN_FLAG_HIDDEN)) {
+      region_preview->flag |= RGN_FLAG_HIDDEN;
+      region_preview->v2d.flag &= ~V2D_IS_INITIALISED;
+      WM_event_remove_handlers((bContext *)C, &region_preview->handlers);
       view_changed = true;
     }
-    if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
-      ar_preview->alignment = RGN_ALIGN_NONE;
+    if (region_preview && region_preview->alignment != RGN_ALIGN_NONE) {
+      region_preview->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
 
   if (channels_visible) {
-    if (ar_channels && (ar_channels->flag & RGN_FLAG_HIDDEN)) {
-      ar_channels->flag &= ~RGN_FLAG_HIDDEN;
-      ar_channels->v2d.flag &= ~V2D_IS_INITIALISED;
+    if (region_channels && (region_channels->flag & RGN_FLAG_HIDDEN)) {
+      region_channels->flag &= ~RGN_FLAG_HIDDEN;
+      region_channels->v2d.flag &= ~V2D_IS_INITIALISED;
       view_changed = true;
     }
-    if (ar_channels && ar_channels->alignment != RGN_ALIGN_LEFT) {
-      ar_channels->alignment = RGN_ALIGN_LEFT;
+    if (region_channels && region_channels->alignment != RGN_ALIGN_LEFT) {
+      region_channels->alignment = RGN_ALIGN_LEFT;
       view_changed = true;
     }
   }
   else {
-    if (ar_channels && !(ar_channels->flag & RGN_FLAG_HIDDEN)) {
-      ar_channels->flag |= RGN_FLAG_HIDDEN;
-      ar_channels->v2d.flag &= ~V2D_IS_INITIALISED;
-      WM_event_remove_handlers((bContext *)C, &ar_channels->handlers);
+    if (region_channels && !(region_channels->flag & RGN_FLAG_HIDDEN)) {
+      region_channels->flag |= RGN_FLAG_HIDDEN;
+      region_channels->v2d.flag &= ~V2D_IS_INITIALISED;
+      WM_event_remove_handlers((bContext *)C, &region_channels->handlers);
       view_changed = true;
     }
-    if (ar_channels && ar_channels->alignment != RGN_ALIGN_NONE) {
-      ar_channels->alignment = RGN_ALIGN_NONE;
+    if (region_channels && region_channels->alignment != RGN_ALIGN_NONE) {
+      region_channels->alignment = RGN_ALIGN_NONE;
       view_changed = true;
     }
   }
diff --git a/source/blender/editors/space_file/file_ops.c b/source/blender/editors/space_file/file_ops.c
index cb574e35422..8c963e32046 100644
--- a/source/blender/editors/space_file/file_ops.c
+++ b/source/blender/editors/space_file/file_ops.c
@@ -1869,7 +1869,7 @@ static int file_smoothscroll_invoke(bContext *C, wmOperator *UNUSED(op), const w
 {
   ScrArea *sa = CTX_wm_area(C);
   SpaceFile *sfile = CTX_wm_space_file(C);
-  ARegion *region, *ar_ctx = CTX_wm_region(C);
+  ARegion *region, *region_ctx = CTX_wm_region(C);
   const bool is_horizontal = (sfile->layout->flag & FILE_LAYOUT_HOR) != 0;
   int i;
 
@@ -2033,7 +2033,7 @@ static int file_smoothscroll_invoke(bContext *C, wmOperator *UNUSED(op), const w
   ED_region_tag_redraw(region);
 
   /* and restore context */
-  CTX_wm_region_set(C, ar_ctx);
+  CTX_wm_region_set(C, region_ctx);
 
   return OPERATOR_FINISHED;
 }
diff --git a/source/blender/editors/space_file/space_file.c b/source/blender/editors/space_file/space_file.c
index 1574dbbeb76..59383626972 100644
--- a/source/blender/editors/space_file/space_file.c
+++ b/source/blender/editors/space_file/space_file.c
@@ -55,7 +55,7 @@
 #include "filelist.h"
 #include "fsmenu.h"
 
-static ARegion *file_execute_region_ensure(ScrArea *sa, ARegion *ar_prev)
+static ARegion *file_execute_region_ensure(ScrArea *sa, ARegion *region_prev)
 {
   ARegion *region;
 
@@ -64,7 +64,7 @@ static ARegion *file_execute_region_ensure(ScrArea *sa, ARegion *ar_prev)
   }
 
   region = MEM_callocN(sizeof(ARegion), "execute region for file");
-  BLI_insertlinkafter(&sa->regionbase, ar_prev, region);
+  BLI_insertlinkafter(&sa->regionbase, region_prev, region);
   region->regiontype = RGN_TYPE_EXECUTE;
   region->alignment = RGN_ALIGN_BOTTOM;
   region->flag = RGN_FLAG_DYNAMIC_SIZE;
@@ -72,7 +72,7 @@ static ARegion *file_execute_region_ensure(ScrArea *sa, ARegion *ar_prev)
   return region;
 }
 
-static ARegion *file_tool_props_region_ensure(ScrArea *sa, ARegion *ar_prev)
+static ARegion *file_tool_props_region_ensure(ScrArea *sa, ARegion *region_prev)
 {
   ARegion *region;
 
@@ -82,7 +82,7 @@ static ARegion *file_tool_props_region_ensure(ScrArea *sa, ARegion *ar_prev)
 
   /* add subdiv level; after execute region */
   region = MEM_callocN(sizeof(ARegion), "tool props for file");
-  BLI_insertlinkafter(&sa->regionbase, ar_prev, region);
+  BLI_insertlinkafter(&sa->regionbase, region_prev, region);
   region->regiontype = RGN_TYPE_TOOL_PROPS;
   region->alignment = RGN_ALIGN_RIGHT;
 
@@ -232,31 +232,31 @@ static void file_ensure_valid_region_state(bContext *C,
                                            SpaceFile *sfile,
                                            FileSelectParams *params)
 {
-  ARegion *ar_ui = BKE_area_find_region_type(sa, RGN_TYPE_UI);
-  ARegion *ar_props = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_PROPS);
-  ARegion *ar_execute = BKE_area_find_region_type(sa, RGN_TYPE_EXECUTE);
+  ARegion *region_ui = BKE_area_find_region_type(sa, RGN_TYPE_UI);
+  ARegion *region_props = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_PROPS);
+  ARegion *region_execute = BKE_area_find_region_type(sa, RGN_TYPE_EXECUTE);
   bool needs_init = false; /* To avoid multiple ED_area_initialize() calls. */
 
   /* If there's an file-operation, ensure we have the option and execute region */
-  if (sfile->op && (ar_props == NULL)) {
-    ar_execute = file_execute_region_ensure(sa, ar_ui);
-    ar_props = file_tool_props_region_ensure(sa, ar_execute);
+  if (sfile->op && (region_props == NULL)) {
+    region_execute = file_execute_region_ensure(sa, region_ui);
+    region_props = file_tool_props_region_ensure(sa, region_execute);
 
     if (params->flag & FILE_HIDE_TOOL_PROPS) {
-      ar_props->flag |= RGN_FLAG_HIDDEN;
+      region_props->flag |= RGN_FLAG_HIDDEN;
     }
     else {
-      ar_props->flag &= ~RGN_FLAG_HIDDEN;
+      region_props->flag &= ~RGN_FLAG_HIDDEN;
     }
 
     needs_init = true;
   }
   /* If there's _no_ file-operation, ensure we _don't_ have the option and execute region */
-  else if ((sfile->op == NULL) && (ar_props != NULL)) {
-    BLI_assert(ar_execute != NULL);
+  else if ((sfile->op == NULL) && (region_props != NULL)) {
+    BLI_assert(region_execute != NULL);
 
-    ED_region_remove(C, sa, ar_props);
-    ED_region_remove(C, sa, ar_execute);
+    ED_region_remove(C, sa, region_props);
+    ED_region_remove(C, sa, region_execute);
     needs_init = true;
   }
 
diff --git a/source/blender/editors/space_graph/graph_utils.c b/source/blender/editors/space_graph/graph_utils.c
index 0af94904ba6..34c1958734d 100644
--- a/source/blender/editors/space_graph/graph_utils.c
+++ b/source/blender/editors/space_graph/graph_utils.c
@@ -62,14 +62,14 @@ void ED_drivers_editor_init(bContext *C, ScrArea *sa)
   sipo->mode = SIPO_MODE_DRIVERS;
 
   /* Show Properties Region (or else the settings can't be edited) */
-  ARegion *ar_props = BKE_area_find_region_type(sa, RGN_TYPE_UI);
-  if (ar_props) {
-    UI_panel_category_active_set(ar_props, "Drivers");
+  ARegion *region_props = BKE_area_find_region_type(sa, RGN_TYPE_UI);
+  if (region_props) {
+    UI_panel_category_active_set(region_props, "Drivers");
 
-    ar_props->flag &= ~RGN_FLAG_HIDDEN;
+    region_props->flag &= ~RGN_FLAG_HIDDEN;
     /* XXX: Adjust width of this too? */
 
-    ED_region_visibility_change_update(C, sa, ar_props);
+    ED_region_visibility_change_update(C, sa, region_props);
   }
   else {
     printf("%s: Couldn't find properties region for Drivers Editor - %p\n", __func__, sa);
@@ -79,15 +79,15 @@ void ED_drivers_editor_init(bContext *C, ScrArea *sa)
   /* TODO: Have a way of not resetting this every time?
    * (e.g. So that switching back and forth between editors doesn't keep jumping?)
    */
-  ARegion *ar_main = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
-  if (ar_main) {
+  ARegion *region_main = BKE_area_find_region_type(sa, RGN_TYPE_WINDOW);
+  if (region_main) {
     /* XXX: Ideally we recenter based on the range instead... */
-    ar_main->v2d.tot.xmin = -2.0f;
-    ar_main->v2d.tot.ymin = -2.0f;
-    ar_main->v2d.tot.xmax = 2.0f;
-    ar_main->v2d.tot.ymax = 2.0f;
+    region_main->v2d.tot.xmin = -2.0f;
+    region_main->v2d.tot.ymin = -2.0f;
+    region_main->v2d.tot.xmax = 2.0f;
+    region_main->v2d.tot.ymax = 2.0f;
 
-    ar_main->v2d.cur = ar_main->v2d.tot;
+    region_main->v2d.cur = region_main->v2d.tot;
   }
 }
 
diff --git a/source/blender/editors/space_sequencer/space_sequencer.c b/source/blender/editors/space_sequencer/space_sequencer.c
index 447bf27099d..2cd3f624455 100644
--- a/source/blender/editors/space_sequencer/space_sequencer.c
+++ b/source/blender/editors/space_sequencer/space_sequencer.c
@@ -223,88 +223,88 @@ static void sequencer_refresh(const bContext *C, ScrArea *sa)
   wmWindowManager *wm = CTX_wm_manager(C);
   wmWindow *window = CTX_wm_window(C);
   SpaceSeq *sseq = (SpaceSeq *)sa->spacedata.first;
-  ARegion *ar_main = sequencer_find_region(sa, RGN_TYPE_WINDOW);
-  ARegion *ar_preview = sequencer_find_region(sa, RGN_TYPE_PREVIEW);
+  ARegion *region_main = sequencer_find_region(sa, RGN_TYPE_WINDOW);
+  ARegion *region_preview = sequencer_find_region(sa, RGN_TYPE_PREVIEW);
   bool view_changed = false;
 
   switch (sseq->view) {
     case SEQ_VIEW_SEQUENCE:
-      if (ar_main && (ar_main->flag & RGN_FLAG_HIDDEN)) {
-        ar_main->flag &= ~RGN_FLAG_HIDDEN;
-        ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
+      if (region_main && (region_main->flag & RGN_FLAG_HIDDEN)) {
+        region_main->flag &= ~RGN_FLAG_HIDDEN;
+        region_main->v2d.flag &= ~V2D_IS_INITIALISED;
         view_changed = true;
       }
-      if (ar_preview && !(ar_preview->flag & RGN_FLAG_HIDDEN)) {
-        ar_preview->flag |= RGN_FLAG_HIDDEN;
-        ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
-        WM_event_remove_handlers((bContext *)C, &ar_preview->handlers);
+      if (region_preview && !(region_preview->flag & RGN_FLAG_HIDDEN)) {
+        region_preview->flag |= RGN_FLAG_HIDDEN;
+        region_preview->v2d.flag &= ~V2D_IS_INITIALISED;
+        WM_event_remove_handlers((bContext *)C, &region_preview->handlers);
         view_changed = true;
       }
-      if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
-        ar_main->alignment = RGN_ALIGN_NONE;
+      if (region_main && region_main->alignment != RGN_ALIGN_NONE) {
+        region_main->alignment = RGN_ALIGN_NONE;
         view_changed = true;
       }
-      if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
-        ar_preview->alignment = RGN_ALIGN_NONE;
+      if (region_preview && region_preview->alignment != RGN_ALIGN_NONE) {
+        region_preview->alignment = RGN_ALIGN_NONE;
         view_changed = true;
       }
       break;
     case SEQ_VIEW_PREVIEW:
-      if (ar_main && !(ar_main->flag & RGN_FLAG_HIDDEN)) {
-        ar_main->flag |= RGN_FLAG_HIDDEN;
-        ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
-        WM_event_remove_handlers((bContext *)C, &ar_main->handlers);
+      if (region_main && !(region_main->flag & RGN_FLAG_HIDDEN)) {
+        region_main->flag |= RGN_FLAG_HIDDEN;
+        region_main->v2d.flag &= ~V2D_IS_INITIALISED;
+        WM_event_remove_handlers((bContext *)C, &region_main->handlers);
         view_changed = true;
       }
-      if (ar_preview && (ar_preview->flag & RGN_FLAG_HIDDEN)) {
-        ar_preview->flag &= ~RGN_FLAG_HIDDEN;
-        ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
-        ar_preview->v2d.cur = ar_preview->v2d.tot;
+      if (region_preview && (region_preview->flag & RGN_FLAG_HIDDEN)) {
+        region_preview->flag &= ~RGN_FLAG_HIDDEN;
+        region_preview->v2d.flag &= ~V2D_IS_INITIALISED;
+        region_preview->v2d.cur = region_preview->v2d.tot;
         view_changed = true;
       }
-      if (ar_main && ar_main->alignment != RGN_ALIGN_NONE) {
-        ar_main->alignment = RGN_ALIGN_NONE;
+      if (region_main && region_main->alignment != RGN_ALIGN_NONE) {
+        region_main->alignment = RGN_ALIGN_NONE;
         view_changed = true;
       }
-      if (ar_preview && ar_preview->alignment != RGN_ALIGN_NONE) {
-        ar_preview->alignment = RGN_ALIGN_NONE;
+      if (region_preview && region_preview->alignment != RGN_ALIGN_NONE) {
+        region_preview->alignment = RGN_ALIGN_NONE;
         view_changed = true;
       }
       break;
     case SEQ_VIEW_SEQUENCE_PREVIEW:
-      if (ar_main && ar_preview) {
+      if (region_main && region_preview) {
         /* Get available height (without DPI correction). */
         const float height = (sa->winy - ED_area_headersize()) / UI_DPI_FAC;
 
         /* We reuse hidden region's size, allows to find same layout as before if we just switch
          * between one 'full window' view and the combined one. This gets lost if we switch to both
          * 'full window' views before, though... Better than nothing. */
-        if (ar_main->flag & RGN_FLAG_HIDDEN) {
-          ar_main->flag &= ~RGN_FLAG_HIDDEN;
-          ar_main->v2d.flag &= ~V2D_IS_INITIALISED;
-          ar_preview->sizey = (int)(height - ar_main->sizey);
+        if (region_main->flag & RGN_FLAG_HIDDEN) {
+          region_main->flag &= ~RGN_FLAG_HIDDEN;
+          region_main->v2d.flag &= ~V2D_IS_INITIALISED;
+          region_preview->sizey = (int)(height - region_main->sizey);
           view_changed = true;
         }
-        if (ar_preview->flag & RGN_FLAG_HIDDEN) {
-          ar_preview->flag &= ~RGN_FLAG_HIDDEN;
-          ar_preview->v2d.flag &= ~V2D_IS_INITIALISED;
-          ar_preview->v2d.cur = ar_preview->v2d.tot;
-          ar_main->sizey = (int)(height - ar_preview->sizey);
+        if (region_preview->flag & RGN_FLAG_HIDDEN) {
+          region_preview->flag &= ~RGN_FLAG_HIDDEN;
+          region_preview->v2d.flag &= ~V2D_IS_INITIALISED;
+          region_preview->v2d.cur = region_preview->v2d.tot;
+          region_main->sizey = (int)(height - region_preview->sizey);
           view_changed = true;
         }
-        if (ar_main->alignment != RGN_ALIGN_NONE) {
-          ar_main->alignment = RGN_ALIGN_NONE;
+        if (region_main->alignment != RGN_ALIGN_NONE) {
+          region_main->alignment = RGN_ALIGN_NONE;
           view_changed = true;
         }
-        if (ar_preview->alignment != RGN_ALIGN_TOP) {
-          ar_preview->alignment = RGN_ALIGN_TOP;
+        if (region_preview->alignment != RGN_ALIGN_TOP) {
+          region_preview->alignment = RGN_ALIGN_TOP;
           view_changed = true;
         }
         /* Final check that both preview and main height are reasonable! */
-        if (ar_preview->sizey < 10 || ar_main->sizey < 10 ||
-            ar_preview->sizey + ar_main->sizey > height) {
-          ar_preview->sizey = (int)(height * 0.4f + 0.5f);
-          ar_main->sizey = (int)(height - ar_preview->sizey);
+        if (region_preview->sizey < 10 || region_main->sizey < 10 ||
+            region_preview->sizey + region_main->sizey > height) {
+          region_preview->sizey = (int)(height * 0.4f + 0.5f);
+          region_main->sizey = (int)(height - region_preview->sizey);
           view_changed = true;
         }
       }
diff --git a/source/blender/editors/space_view3d/space_view3d.c b/source/blender/editors/space_view3d/space_view3d.c
index 13c5bddd3bf..e5f1de7d5eb 100644
--- a/source/blender/editors/space_view3d/space_view3d.c
+++ b/source/blender/editors/space_view3d/space_view3d.c
@@ -101,12 +101,12 @@ RegionView3D *ED_view3d_context_rv3d(bContext *C)
 
 /* ideally would return an rv3d but in some cases the region is needed too
  * so return that, the caller can then access the region->regiondata */
-bool ED_view3d_context_user_region(bContext *C, View3D **r_v3d, ARegion **r_ar)
+bool ED_view3d_context_user_region(bContext *C, View3D **r_v3d, ARegion **r_region)
 {
   ScrArea *sa = CTX_wm_area(C);
 
   *r_v3d = NULL;
-  *r_ar = NULL;
+  *r_region = NULL;
 
   if (sa && sa->spacetype == SPACE_VIEW3D) {
     ARegion *region = CTX_wm_region(C);
@@ -117,11 +117,11 @@ bool ED_view3d_context_user_region(bContext *C, View3D **r_v3d, ARegion **r_ar)
       if ((region->regiontype == RGN_TYPE_WINDOW) && (rv3d = region->regiondata) &&
           (rv3d->viewlock & RV3D_LOCK_ROTATION) == 0) {
         *r_v3d = v3d;
-        *r_ar = region;
+        *r_region = region;
         return true;
       }
       else {
-        if (ED_view3d_area_user_region(sa, v3d, r_ar)) {
+        if (ED_view3d_area_user_region(sa, v3d, r_region)) {
           *r_v3d = v3d;
           return true;
         }
@@ -136,11 +136,11 @@ bool ED_view3d_context_user_region(bContext *C, View3D **r_v3d, ARegion **r_ar)
  * Similar to #ED_view3d_context_user_region() but does not use context. Always performs a lookup.
  * Also works if \a v3d is not the active space.
  */
-bool ED_view3d_area_user_region(const ScrArea *sa, const View3D *v3d, ARegion **r_ar)
+bool ED_view3d_area_user_region(const ScrArea *sa, const View3D *v3d, ARegion **r_region)
 {
   RegionView3D *rv3d = NULL;
-  ARegion *ar_unlock_user = NULL;
-  ARegion *ar_unlock = NULL;
+  ARegion *region_unlock_user = NULL;
+  ARegion *region_unlock = NULL;
   const ListBase *region_list = (v3d == sa->spacedata.first) ? &sa->regionbase : &v3d->regionbase;
 
   BLI_assert(v3d->spacetype == SPACE_VIEW3D);
@@ -150,9 +150,9 @@ bool ED_view3d_area_user_region(const ScrArea *sa, const View3D *v3d, ARegion **
     if (region->regiondata && region->regiontype == RGN_TYPE_WINDOW) {
       rv3d = region->regiondata;
       if ((rv3d->viewlock & RV3D_LOCK_ROTATION) == 0) {
-        ar_unlock = region;
+        region_unlock = region;
         if (rv3d->persp == RV3D_PERSP || rv3d->persp == RV3D_CAMOB) {
-          ar_unlock_user = region;
+          region_unlock_user = region;
           break;
         }
       }
@@ -160,13 +160,13 @@ bool ED_view3d_area_user_region(const ScrArea *sa, const View3D *v3d, ARegion **
   }
 
   /* camera/perspective view get priority when the active region is locked */
-  if (ar_unlock_user) {
-    *r_ar = ar_unlock_user;
+  if (region_unlock_user) {
+    *r_region = region_unlock_user;
     return true;
   }
 
-  if (ar_unlock) {
-    *r_ar = ar_unlock;
+  if (region_unlock) {
+    *r_region = region_unlock;
     return true;
   }
 
diff --git a/source/blender/editors/space_view3d/view3d_edit.c b/source/blender/editors/space_view3d/view3d_edit.c
index e650f5581ff..09be73c87d1 100644
--- a/source/blender/editors/space_view3d/view3d_edit.c
+++ b/source/blender/editors/space_view3d/view3d_edit.c
@@ -529,10 +529,10 @@ static void viewops_data_create(bContext *C,
         negate_v3_v3(rv3d->ofs, dvec);
       }
       else {
-        const float mval_ar_mid[2] = {(float)vod->region->winx / 2.0f,
-                                      (float)vod->region->winy / 2.0f};
+        const float mval_region_mid[2] = {(float)vod->region->winx / 2.0f,
+                                          (float)vod->region->winy / 2.0f};
 
-        ED_view3d_win_to_3d(vod->v3d, vod->region, vod->dyn_ofs, mval_ar_mid, rv3d->ofs);
+        ED_view3d_win_to_3d(vod->v3d, vod->region, vod->dyn_ofs, mval_region_mid, rv3d->ofs);
         negate_v3(rv3d->ofs);
       }
       negate_v3(vod->dyn_ofs);
diff --git a/source/blender/editors/space_view3d/view3d_utils.c b/source/blender/editors/space_view3d/view3d_utils.c
index 2637fb6d1db..5db26e26f0b 100644
--- a/source/blender/editors/space_view3d/view3d_utils.c
+++ b/source/blender/editors/space_view3d/view3d_utils.c
@@ -866,7 +866,7 @@ void view3d_boxview_copy(ScrArea *sa, ARegion *region)
 /* 'clip' is used to know if our clip setting has changed */
 void ED_view3d_quadview_update(ScrArea *sa, ARegion *region, bool do_clip)
 {
-  ARegion *ar_sync = NULL;
+  ARegion *region_sync = NULL;
   RegionView3D *rv3d = region->regiondata;
   short viewlock;
   /* this function copies flags from the first of the 3 other quadview
@@ -892,15 +892,15 @@ void ED_view3d_quadview_update(ScrArea *sa, ARegion *region, bool do_clip)
         rv3d->rflag &= ~RV3D_BOXCLIP;
       }
 
-      /* use ar_sync so we sync with one of the aligned views below
+      /* use region_sync so we sync with one of the aligned views below
        * else the view jumps on changing view settings like 'clip'
        * since it copies from the perspective view */
-      ar_sync = region;
+      region_sync = region;
     }
   }
 
   if (RV3D_LOCK_FLAGS(rv3d) & RV3D_BOXVIEW) {
-    view3d_boxview_sync(sa, ar_sync ? ar_sync : sa->regionbase.last);
+    view3d_boxview_sync(sa, region_sync ? region_sync : sa->regionbase.last);
   }
 
   /* ensure locked regions have an axis, locked user views don't make much sense */
diff --git a/source/blender/editors/space_view3d/view3d_view.c b/source/blender/editors/space_view3d/view3d_view.c
index 522d1a15e3f..3dc5b3025aa 100644
--- a/source/blender/editors/space_view3d/view3d_view.c
+++ b/source/blender/editors/space_view3d/view3d_view.c
@@ -615,17 +615,18 @@ static void sync_viewport_camera_smoothview(bContext *C,
           if (v3d->scenelock) {
             ListBase *lb = (space_link == area->spacedata.first) ? &area->regionbase :
                                                                    &space_link->regionbase;
-            for (ARegion *other_ar = lb->first; other_ar != NULL; other_ar = other_ar->next) {
-              if (other_ar->regiontype == RGN_TYPE_WINDOW) {
-                if (other_ar->regiondata) {
-                  RegionView3D *other_rv3d = other_ar->regiondata;
+            for (ARegion *other_region = lb->first; other_region != NULL;
+                 other_region = other_region->next) {
+              if (other_region->regiontype == RGN_TYPE_WINDOW) {
+                if (other_region->regiondata) {
+                  RegionView3D *other_rv3d = other_region->regiondata;
                   if (other_rv3d->persp == RV3D_CAMOB) {
                     Object *other_camera_old = other_v3d->camera;
                     other_v3d->camera = ob;
                     ED_view3d_lastview_store(other_rv3d);
                     ED_view3d_smooth_view(C,
                                           other_v3d,
-                                          other_ar,
+                                          other_region,
                                           smooth_viewtx,
                                           &(const V3D_SmoothParams){
                                               .camera_old = other_camera_old,
@@ -704,9 +705,9 @@ static int view3d_setobjectascamera_exec(bContext *C, wmOperator *op)
 bool ED_operator_rv3d_user_region_poll(bContext *C)
 {
   View3D *v3d_dummy;
-  ARegion *ar_dummy;
+  ARegion *region_dummy;
 
-  return ED_view3d_context_user_region(C, &v3d_dummy, &ar_dummy);
+  return ED_view3d_context_user_region(C, &v3d_dummy, &region_dummy);
 }
 
 void VIEW3D_OT_object_as_camera(wmOperatorType *ot)
diff --git a/source/blender/editors/undo/ed_undo.c b/source/blender/editors/undo/ed_undo.c
index 123fd5f35da..9db957f8031 100644
--- a/source/blender/editors/undo/ed_undo.c
+++ b/source/blender/editors/undo/ed_undo.c
@@ -558,11 +558,11 @@ int ED_undo_operator_repeat(bContext *C, wmOperator *op)
     struct Scene *scene = CTX_data_scene(C);
 
     /* keep in sync with logic in view3d_panel_operator_redo() */
-    ARegion *ar_orig = CTX_wm_region(C);
-    ARegion *ar_win = BKE_area_find_region_active_win(CTX_wm_area(C));
+    ARegion *region_orig = CTX_wm_region(C);
+    ARegion *region_win = BKE_area_find_region_active_win(CTX_wm_area(C));
 
-    if (ar_win) {
-      CTX_wm_region_set(C, ar_win);
+    if (region_win) {
+      CTX_wm_region_set(C, region_win);
     }
 
     if ((WM_operator_repeat_check(C, op)) && (WM_operator_poll(C, op->type)) &&
@@ -585,9 +585,9 @@ int ED_undo_operator_repeat(bContext *C, wmOperator *op)
       if (op->type->check) {
         if (op->type->check(C, op)) {
           /* check for popup and re-layout buttons */
-          ARegion *ar_menu = CTX_wm_menu(C);
-          if (ar_menu) {
-            ED_region_tag_refresh_ui(ar_menu);
+          ARegion *region_menu = CTX_wm_menu(C);
+          if (region_menu) {
+            ED_region_tag_refresh_ui(region_menu);
           }
         }
       }
@@ -610,7 +610,7 @@ int ED_undo_operator_repeat(bContext *C, wmOperator *op)
     }
 
     /* set region back */
-    CTX_wm_region_set(C, ar_orig);
+    CTX_wm_region_set(C, region_orig);
   }
   else {
     CLOG_WARN(&LOG, "called with NULL 'op'");
diff --git a/source/blender/makesrna/intern/rna_space.c b/source/blender/makesrna/intern/rna_space.c
index cf515792252..7bff13bf1a6 100644
--- a/source/blender/makesrna/intern/rna_space.c
+++ b/source/blender/makesrna/intern/rna_space.c
@@ -576,31 +576,31 @@ static ScrArea *rna_area_from_space(PointerRNA *ptr)
 static void area_region_from_regiondata(bScreen *sc,
                                         void *regiondata,
                                         ScrArea **r_sa,
-                                        ARegion **r_ar)
+                                        ARegion **r_region)
 {
   ScrArea *sa;
   ARegion *region;
 
   *r_sa = NULL;
-  *r_ar = NULL;
+  *r_region = NULL;
 
   for (sa = sc->areabase.first; sa; sa = sa->next) {
     for (region = sa->regionbase.first; region; region = region->next) {
       if (region->regiondata == regiondata) {
         *r_sa = sa;
-        *r_ar = region;
+        *r_region = region;
         return;
       }
     }
   }
 }
 
-static void rna_area_region_from_regiondata(PointerRNA *ptr, ScrArea **r_sa, ARegion **r_ar)
+static void rna_area_region_from_regiondata(PointerRNA *ptr, ScrArea **r_sa, ARegion **r_region)
 {
   bScreen *sc = (bScreen *)ptr->owner_id;
   void *regiondata = ptr->data;
 
-  area_region_from_regiondata(sc, regiondata, r_sa, r_ar);
+  area_region_from_regiondata(sc, regiondata, r_sa, r_region);
 }
 
 /* -------------------------------------------------------------------- */
@@ -680,9 +680,9 @@ static void rna_Space_show_region_header_set(PointerRNA *ptr, bool value)
   bool value_for_tool_header = value;
   if (value == true) {
     ScrArea *sa = rna_area_from_space(ptr);
-    ARegion *ar_tool_header = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_HEADER);
-    if (ar_tool_header != NULL) {
-      value_for_tool_header = !(ar_tool_header->flag & RGN_FLAG_HIDDEN_BY_USER);
+    ARegion *region_tool_header = BKE_area_find_region_type(sa, RGN_TYPE_TOOL_HEADER);
+    if (region_tool_header != NULL) {
+      value_for_tool_header = !(region_tool_header->flag & RGN_FLAG_HIDDEN_BY_USER);
     }
   }
   rna_Space_bool_from_region_flag_set_by_type(
diff --git a/source/blender/windowmanager/intern/wm_draw.c b/source/blender/windowmanager/intern/wm_draw.c
index ebfdd8a5f6a..b8bee118e3e 100644
--- a/source/blender/windowmanager/intern/wm_draw.c
+++ b/source/blender/windowmanager/intern/wm_draw.c
@@ -213,7 +213,7 @@ static void wm_region_test_gizmo_do_draw(bContext *C,
        gzgroup = gzgroup->next) {
     if (tag_redraw && (gzgroup->type->flag & WM_GIZMOGROUPTYPE_VR_REDRAWS)) {
       ScrArea *ctx_sa = CTX_wm_area(C);
-      ARegion *ctx_ar = CTX_wm_region(C);
+      ARegion *ctx_region = CTX_wm_region(C);
 
       CTX_wm_area_set(C, sa);
       CTX_wm_region_set(C, region);
@@ -224,7 +224,7 @@ static void wm_region_test_gizmo_do_draw(bContext *C,
 
       /* Reset. */
       CTX_wm_area_set(C, ctx_sa);
-      CTX_wm_region_set(C, ctx_ar);
+      CTX_wm_region_set(C, ctx_region);
     }
 
     for (wmGizmo *gz = gzgroup->gizmos.first; gz; gz = gz->next) {
@@ -1052,13 +1052,13 @@ void WM_redraw_windows(bContext *C)
 {
   wmWindow *win_prev = CTX_wm_window(C);
   ScrArea *area_prev = CTX_wm_area(C);
-  ARegion *ar_prev = CTX_wm_region(C);
+  ARegion *region_prev = CTX_wm_region(C);
 
   wm_draw_update(C);
 
   CTX_wm_window_set(C, win_prev);
   CTX_wm_area_set(C, area_prev);
-  CTX_wm_region_set(C, ar_prev);
+  CTX_wm_region_set(C, region_prev);
 }
 
 /** \} */
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index 1a794e9bf0b..8d7155b5ea8 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -839,7 +839,7 @@ static void wm_operator_reports(bContext *C, wmOperator *op, int retval, bool ca
       /* FIXME, temp setting window, see other call to UI_popup_menu_reports for why */
       wmWindow *win_prev = CTX_wm_window(C);
       ScrArea *area_prev = CTX_wm_area(C);
-      ARegion *ar_prev = CTX_wm_region(C);
+      ARegion *region_prev = CTX_wm_region(C);
 
       if (win_prev == NULL) {
         CTX_wm_window_set(C, CTX_wm_manager(C)->windows.first);
@@ -849,7 +849,7 @@ static void wm_operator_reports(bContext *C, wmOperator *op, int retval, bool ca
 
       CTX_wm_window_set(C, win_prev);
       CTX_wm_area_set(C, area_prev);
-      CTX_wm_region_set(C, ar_prev);
+      CTX_wm_region_set(C, region_prev);
     }
   }
 
@@ -2296,7 +2296,7 @@ static int wm_handler_fileselect_do(bContext *C,
            * it can be removed without breaking anything but then no linking errors - campbell */
           wmWindow *win_prev = CTX_wm_window(C);
           ScrArea *area_prev = CTX_wm_area(C);
-          ARegion *ar_prev = CTX_wm_region(C);
+          ARegion *region_prev = CTX_wm_region(C);
 
           if (win_prev == NULL) {
             CTX_wm_window_set(C, CTX_wm_manager(C)->windows.first);
@@ -2314,7 +2314,7 @@ static int wm_handler_fileselect_do(bContext *C,
 
           CTX_wm_window_set(C, win_prev);
           CTX_wm_area_set(C, area_prev);
-          CTX_wm_region_set(C, ar_prev);
+          CTX_wm_region_set(C, region_prev);
         }
 
         /* for WM_operator_pystring only, custom report handling is done above */
diff --git a/source/blender/windowmanager/intern/wm_operators.c b/source/blender/windowmanager/intern/wm_operators.c
index c3446a016f1..4a4e373d15e 100644
--- a/source/blender/windowmanager/intern/wm_operators.c
+++ b/source/blender/windowmanager/intern/wm_operators.c
@@ -3201,13 +3201,13 @@ static void redraw_timer_step(bContext *C,
     CTX_wm_menu_set(C, NULL);
 
     for (sa_iter = screen->areabase.first; sa_iter; sa_iter = sa_iter->next) {
-      ARegion *ar_iter;
+      ARegion *region_iter;
       CTX_wm_area_set(C, sa_iter);
 
-      for (ar_iter = sa_iter->regionbase.first; ar_iter; ar_iter = ar_iter->next) {
-        if (ar_iter->visible) {
-          CTX_wm_region_set(C, ar_iter);
-          wm_draw_region_test(C, sa_iter, ar_iter);
+      for (region_iter = sa_iter->regionbase.first; region_iter; region_iter = region_iter->next) {
+        if (region_iter->visible) {
+          CTX_wm_region_set(C, region_iter);
+          wm_draw_region_test(C, sa_iter, region_iter);
         }
       }
     }
diff --git a/source/blender/windowmanager/intern/wm_splash_screen.c b/source/blender/windowmanager/intern/wm_splash_screen.c
index 9c7ed52b0f9..0a1553cb3e1 100644
--- a/source/blender/windowmanager/intern/wm_splash_screen.c
+++ b/source/blender/windowmanager/intern/wm_splash_screen.c
@@ -71,8 +71,8 @@ static uiBlock *wm_block_create_splash(bContext *C, ARegion *region, void *arg_u
 
 static void wm_block_splash_refreshmenu(bContext *C, void *UNUSED(arg_block), void *UNUSED(arg))
 {
-  ARegion *ar_menu = CTX_wm_menu(C);
-  ED_region_tag_refresh_ui(ar_menu);
+  ARegion *region_menu = CTX_wm_menu(C);
+  ED_region_tag_refresh_ui(region_menu);
 }
 
 static void wm_block_splash_add_label(uiBlock *block, const char *label, int x, int *y)
diff --git a/source/blender/windowmanager/intern/wm_toolsystem.c b/source/blender/windowmanager/intern/wm_toolsystem.c
index 551250ec747..1abef2ec173 100644
--- a/source/blender/windowmanager/intern/wm_toolsystem.c
+++ b/source/blender/windowmanager/intern/wm_toolsystem.c
@@ -759,7 +759,7 @@ void WM_toolsystem_update_from_context_view3d(bContext *C)
   if (!BLI_listbase_is_single(&wm->windows)) {
     wmWindow *win_prev = CTX_wm_window(C);
     ScrArea *area_prev = CTX_wm_area(C);
-    ARegion *ar_prev = CTX_wm_region(C);
+    ARegion *region_prev = CTX_wm_region(C);
 
     for (wmWindow *win = wm->windows.first; win; win = win->next) {
       if (win != win_prev) {
@@ -772,7 +772,7 @@ void WM_toolsystem_update_from_context_view3d(bContext *C)
 
           CTX_wm_window_set(C, win_prev);
           CTX_wm_area_set(C, area_prev);
-          CTX_wm_region_set(C, ar_prev);
+          CTX_wm_region_set(C, region_prev);
         }
       }
     }
diff --git a/source/blender/windowmanager/intern/wm_tooltip.c b/source/blender/windowmanager/intern/wm_tooltip.c
index da2afda5e24..4d64acefca4 100644
--- a/source/blender/windowmanager/intern/wm_tooltip.c
+++ b/source/blender/windowmanager/intern/wm_tooltip.c
@@ -119,7 +119,7 @@ void WM_tooltip_init(bContext *C, wmWindow *win)
 
   {
     ScrArea *area_prev = CTX_wm_area(C);
-    ARegion *ar_prev = CTX_wm_region(C);
+    ARegion *region_prev = CTX_wm_region(C);
     CTX_wm_area_set(C, screen->tool_tip->area_from);
     CTX_wm_region_set(C, screen->tool_tip->region_from);
     screen->tool_tip->region = screen->tool_tip->init(C,
@@ -128,7 +128,7 @@ void WM_tooltip_init(bContext *C, wmWindow *win)
                                                       &pass_delay,
                                                       &screen->tool_tip->exit_on_event);
     CTX_wm_area_set(C, area_prev);
-    CTX_wm_region_set(C, ar_prev);
+    CTX_wm_region_set(C, region_prev);
   }
 
   copy_v2_v2_int(screen->tool_tip->event_xy, &win->eventstate->x);