The slicing frame of a belt object started at its lowest vertex, but the
belt under the leading end of an overhang lies below that, by the
overhang's length times the tilt's shear. Every support generator works
in layers at z >= 0, so none of them could reach it: normal supports
stopped at the object's own lowest layer, and the two tree generators
each carried a stack of hacks to extend themselves below it (a post-hoc
copy of the lowest base area in TreeSupport, "virtual belt raft layers"
in TreeSupport3D/TreeModelVolumes), sized from the pre-rotation bbox
and capped at global z = 0, which is only right for the trailing half
of the belt.
Start the frame at the lowest belt-floor point under the footprint
instead, less a 10 mm margin along the belt for the base of a support
column (BeltSliceStrategy::apply_preslice_transforms and
BeltTransformPipeline::compute_belt_height_and_floor agree on it). The
layers between it and the first vertex come out empty, which belt
slicing already tolerates, and the generators need no extension at all:
- normal supports: the generator anchors its layer grid at the frame
origin, so run it in the object frame and shift the global belt Z
offset onto the result afterwards, as organic supports already did.
With the offset on the object layers a top contact at negative z
turned the intermediate-layer count negative and the generator
allocated layers until the kernel killed it (any overhang in the
leading half of the belt). Drop the first-layer flange expansion on a
belt: the first support layer is the leading tip of the support, not
a flange, and inflating it put lines in the air ahead of the belt.
- classic tree: a node now keeps dropping until its whole circle is in
the belt, so the branch tapers to a tip on the belt instead of
stopping, a radius above it, when its centre crosses.
- organic: the belt is no longer a support blocker. A blocker is a
collision, and a branch descending onto one slides off it, down the
tilted belt and ahead of the part; the belt is where branches end,
which the per-layer m_belt_floor clipping already does.
The belt brim is generated after the parallel support step instead of
inside it: belt_brim_obstacles() reads every object's layers and support
layers, which another object's support step rebuilds (and, now, shifts)
at the same time. This is the race behind the Windows arm64 segfault
in "Belt brim of each object precedes its perimeters on its own
filament".
Also: the belt tilt axis moves to Developer mode as its own row (a
shared line is shown by its first option's mode), first_layer_plane
band thickness, belt_support_floor_mode, belt_preslice_global and
gcode_back_transform are retired and presumed on, the gravity arrow is
a plain line along the up direction, and the "Show raw G-code (belt
only)" preview toggle is gone.
Regression test: "Belt supports reach the belt under a leading
overhang" slices a cube with a fin whose underside is parallel to the
layers, 20 mm ahead of the cube and up to 41 mm of slicing Z above the
belt, for normal, organic and classic tree supports, and checks that
the lowest support layer sits on the belt beneath its own lines.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Removed, with the keys added to handle_legacy()'s ignore list so saved
profiles and 3MFs keep loading:
- belt_slice_rotation_global and preslice_remap_global. Both were only
consulted when belt_preslice_global ("Global mesh transforms") was off,
which no profile does; belt_preslice_global is now the single global
mode and is presumed on everywhere the old flags were ORed in
(PrintObjectSlice, BeltBackTransform, BeltGCode, Print::process,
PrintApply). The Belt tilt row is axis + angle only.
- preslice_remap_x/y/z. No profile used the pre-slice axis remap; the belt
tilt axis plus the G-code axis remap cover the machines that exist, and
its implementation only agreed with itself for a plain swap (matrix
columns vs remap_bbox rows). BeltTransformPipeline::build_preslice_remap,
remap_bbox and has_preslice_remap are gone, the forward transform is the
rotation, and the G-code header no longer carries the remap.
- belt_support_z_offset_mode. Saved and invalidated steps, but no support
generator read it.
- first_layer_plane and first_layer_plane_offset, with FirstLayerPlane.cpp.
On every shipped configuration the band is measured from the belt
surface (GCode::belt_height_above_floor) and the evaluator was only
reached for an explicit XY/YZ/XZ choice or a non-zero offset, which
nobody set. first_layer_plane_thickness stays as the band unit,
relabelled "First layer band thickness".
UI: the Machine frame transforms group is five single-option rows (G-code
remap X / Y / Z, Decouple machine-frame tilt, Machine-frame tilt angle;
the angle row is shown only when decoupled) instead of two multi-column
lines, and the remap fields carry full labels.
Also carries the phong.fs struct fix from #16226 so the worktree build
links its shaders.
libslic3r_tests and fff_print_tests pass; clang-tidy diff check clean;
orca_profile_tool.py check clean.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The clang-tidy job on #14394 fails on 129 misc-include-cleaner findings:
the belt sources and tests use std::, Eigen, Point/PrintConfig and
BeltBrim symbols without including the header that provides them, which
only compiled because the precompiled header supplied it. Every include
the job names is added, in each file's existing include style ("../" in
the GCode/ and Support/ subdirectories, quoted libslic3r/ paths in the
GUI and tests). No code changes.
Verified with scripts/clang_tidy_diff.py -p build-tidy --base eb5b9a77b9
(SLIC3R_PCH=OFF compile database, clang-tidy 22.1.8): no findings left.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01L6Kg5igmmMU2YLoK6HrsWV
* Remove Unused Project Includes and Forward-Declare Where a Type Is Only Referenced
Generated with include-what-you-use and applied conservatively. Only OrcaSlicer's own headers, the ones under src/ and tests/, are removed or forward-declared; standard-library and third-party includes are left alone. An include is removed only when both the Release and the Debug configuration leave it unused, never from inside a conditional block, and never from a file with platform-specific blocks, which only gain includes. Files whose only use of a header sits behind a feature or debug macro (libvgcode's OpenGL ES and marker code, the ARACHNE/TESTS_EXPORT_SVGS debug output) keep their includes.
clonable_ptr.hpp gains #pragma once; it had no include guard and was only safe while Config.hpp was its sole includer.
* Remove Unused Project Includes From Files With Platform-Specific Code
A Linux include-what-you-use run cannot see the code inside _WIN32, __APPLE__ or __linux__ blocks, so its verdict is only taken where nothing the removed header declares, directly or through what it includes, is named inside those blocks. Removals also have to hold in both the Release and Debug configuration and never touch a line inside a conditional block.
* Restore the libslic3r Precompiled Header and Direct Includes Lost in the Platform Pass
The platform-file pass treated pchheader.hpp as an ordinary header and
emptied it, and left GUI_Preview.hpp and 14 other files relying on
headers they no longer reached directly.
* Restore MainFrame.hpp in ParamsDialog.cpp for the Windows-Only Reparent Call
* Include Headers That Files Reached Through Ones the Cleanup Removed
* Drop Includes Duplicated by the Cleanup or by Main's Own Additions
* Leave PreciseSeam.cpp as Main Has It After the Precise Seam Rework
Brings belt-printer up to main 4b4a261787. Resolutions:
- G-code header (#15897, #15915): main moved the header, config and
thumbnail block later in _do_export; write_belt_header() moves with it,
still after the thumbnails and outside the BTT_TFT gate.
- _extrude: first-layer acceleration keeps the per-path first-layer plane
test with main's cached nozzle index (#16028); main's set_speed out-param
form (#16108) everywhere else.
- GCodeWriter (#16108): the arc-to-polyline fallback for machine mappings
that cannot express G2/G3 now runs in the out-param extrude_arc_to_xy,
which is the overload GCode calls, and appends to the caller's string.
- GCodeProcessorResult: the belt fields join main's forwarding assign.
- Clipper2 (#15969): belt arrange helpers take Slic3r::Point; the tree
support join types lose their ClipperLib qualifier.
- CLI arrange (#15837): belt printers still reserve no wipe tower.
- Wipe tower options (#15841): the two new sparse-layer toggles are hidden
for belt printers like the rest of the tower options.
- Keyboard shortcuts (#15706): main's registry replaces the old key switch;
the belt view toggle is re-registered in the next commit.
- Print::process: the belt purge-plan undo runs before main's SliceStarted
event.
- scripts/filament_id_snapshot.json: deleted on main (a77209af8f).
- Includes and appended tests: union of both sides.
Every file that included STEP.hpp, directly or not, got namespace fs = boost::filesystem at global scope, and 29 sources and three headers relied on it without saying so. Headers now spell out boost::filesystem, and each source that uses fs declares the alias itself.
The purge plan snaps every object onto one layer grid after the brim is built;
the per-layer brim bands follow their layers but the apron bands below the
first layer carry their own print_z and were left behind, which is why a brim
was refused next to a purge tower object. The shift now moves them too and the
combination is accepted again.
* Add Missing Includes Across src/libslic3r
Every libslic3r source and header now directly includes the headers declaring what it uses, rather than relying on the precompiled header or transitive includes. Generated with clang-tidy misc-include-cleaner, with libslic3r headers spelled libslic3r/... so they resolve outside the library's private include paths. MultiMaterialSegmentation.hpp, Support/SupportParameters.hpp and Format/STEP.hpp are made self-contained by hand.
* Make the libslic3r Headers Compile on Their Own
Each now includes, or forward-declares, what it uses instead of relying on what its includers happened to include first. Left out: I18N.hpp, which errors on purpose when included from GUI code, and VoxelizeCSGMesh.hpp and SLA/bicubic.h, which nothing includes and which no longer compile at all.
* Add the Includes Missing From the Hand-Fixed libslic3r Headers
clang-tidy would not edit these headers while they failed to compile on their own, so the first pass skipped them. With the headers now self-contained, a second pass adds the rest.
* Keep Windows Setup Ahead of the Added libslic3r Includes
Print.cpp and Thread.cpp open with a _WIN32 block that has to come first; without the precompiled header, Print.cpp otherwise reaches windows.h through OCCT with NONLS defined and boost/regex fails. OpenVDBUtils.cpp and SLA/SupportTreeBuilder.cpp had includes inside #ifndef NOMINMAX, which libslic3r defines on Windows, so those were skipped there. .clang-tidy also ignores the MSVC STL and UCRT internals, Boost.Multiprecision's fwd.hpp and CPython's Windows include directory.
* Re-Add libslic3r Includes After the Clipper2 2.0.1 Migration
Rebasing onto main took main's version of the files the Clipper2 migration rewrote, so their added includes are restored here, along with includes for main's new code. Clipper2's individual headers are now ignored by clang-tidy: they only build the Z variant through clipper2_z.hpp, which defines USINGZ first, so including clipper.core.h and the like directly broke ClipperZUtils.cpp.
The purge plan moves objects onto a common layer grid after the brim bands are
built, so the two cannot share a print. The prime tower setting alone still does
not block a brim. The missing-prism warning now counts the filaments the objects
use, as the GUI does.
The purge tower is a model object the GUI creates and sizes, and libslic3r
only purges into one that exists. A multi-filament belt project sliced from
the CLI without it changed filament with nowhere to purge, silently.
Raised in Hanif Koh's review of #14394.
enable_prime_tower stays on for any multi-filament project, but a belt
printer never prints the classic tower and the belt purge prism is an
ordinary object that never takes a brim, so every brim on a multi-filament
belt print was refused for nothing.
Raised in Hanif Koh's review of #14394.
validate() skipped the build-volume height check whenever the machine-frame
transform was active, which is every shipped belt profile, so a 400 mm
object passed on a 300 mm printable_height. The transform only changes how
the height is written to G-code; the clearance check from f682ab5cd3
applies regardless.
Raised in Hanif Koh's review of #14394.
Brings in upstream/belt-printer (the Sept 14 main merge) plus Hanif Koh's
21 review-fix commits from PR #15685, on top of the MachineKinematics
refactor and the purge-prism / tree-support / first-layer-speed fixes.
Conflict resolution:
- BeltGCodeWriter is gone (kinematics refactor), so Hanif's plate-offset
fix for it is ported into GCodeWriter: the first-layer-plane checks in
travel_to_xy / travel_to_xyz / _travel_to_z now evaluate the plate-local
point, and BeltGCode::init_belt_writer hands the stored plate origin to
the writer it installs.
- init_belt_writer(Print&) takes Hanif's signature; the BBL flag is set on
the surviving writer by GCode::_do_export.
- The shared emit_belt_brim_bands() loop keeps the BeltFloorObjectGuard the
local branch added, so apron bands classify first-layer height against
their own object.
- eager_lift keeps effective_type: it now carries set_force_normal_lift().
- GCodeWriter's initializer list follows Hanif's member order with
m_kinematics in its declared position.
- TreeSupport::detect_overhangs uses Hanif's clamped build_plate_tilt_slope()
for the non-belt path and the belt shear for the belt path.
Fan speeds, multi-tool ramming, the tower interface and flush temperature
fallbacks and the custom G-code placeholders now use the extruder variant a
filament prints with on each layer, instead of reading by filament id.
Pressure advance, adaptive pressure advance and its model can now take a
different value for each extruder variant of a filament, such as Standard and
High Flow nozzles, like the other per-variant filament settings. Projects
saved with one value per filament apply it to every variant of that filament,
and the addnorth BBL filaments in the Orca Filament Library are updated to the
per-variant layout.
# Description
Extruder variants (Standard, High Flow, extra high flow) now work on any
printer. Any vendor profile can declare them, and a multi-variant
filament picks up the right variant on every printer. In the sidebar,
users can switch the printer variant and set the nozzle volume type of
each extruder on multi-extruder printers. This also fixes a later
filament printing at the first filament's temperature on a P1S or X1C
with a High Flow nozzle. The profile checks now reject variant arrays of
the wrong size and outdated variant strings. Every shipped vendor
profile passes them, and the orca-profiles skill documents the rules.
Slicing output changes only where the wrong variant was used before.
# Screenshots/Recordings/Graphs
<img width="393" height="218" alt="Screenshot 2026-09-28 at 11 28 07 PM"
src="https://github.com/user-attachments/assets/8bee4b0e-c38c-4039-8c11-096ace6fbad0"
/>
<img width="448" height="267" alt="Screenshot 2026-09-28 at 11 28 37 PM"
src="https://github.com/user-attachments/assets/e767cd97-a5d0-4728-b010-c8ea2bc94ca7"
/>
<img width="746" height="603" alt="Screenshot 2026-09-28 at 11 28 54 PM"
src="https://github.com/user-attachments/assets/23c8af3b-c679-46e5-9fd0-2e43df0449b3"
/>
https://github.com/user-attachments/assets/10d75d72-86a3-42e8-8a95-b1627bd58e91
## Tests
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> Please describe the tests that you have conducted to verify the
changes made in this PR.
-->
<!--
> A guide for users on how to download the artifacts from this PR.
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[How to Download Pull Requests Artifacts for
Testing](https://www.orcaslicer.com/wiki/how_to_download_pr_artifacts)
G-code generation collects errors raised per object, such as an empty
first layer, into one SlicingErrors exception whose own message is just
"Errors". The CLI's generic handler printed that word and recorded the
generic slicing error text, so a headless caller had nothing to act on.
Let Print render the per-object messages with each object's name, and have
the CLI catch SlicingErrors ahead of the generic handler, print that text
and record it as the result's error string. The exit code is unchanged. A
unit test lifts a cube off the bed and checks the message names the object.
* Toolchange Cyclic Order
* Apply cyclic order to first layer
* Unit test
* Copilot fixes
---------
Co-authored-by: Rodrigo Faselli <162915171+RF47@users.noreply.github.com>
gcode_back_transform, first_layer_plane* and belt_printer_infinite_y fell through to invalidate_all_steps(), which re-ran tool ordering, skirt/brim and G-code export on toggles that only affect G-code export.
Merge origin/main (00429da739) into belt-printer.
Conflicts resolved:
- src/CMakeLists.txt: keep both wxInspector workarounds.
- GCodeProcessor.cpp: keep the belt compare_pos / z_for_height lines.
- PrintObjectSlice.cpp: the belt bbox-Z guard also covers main's
printable_region_ids bookkeeping.
- TreeSupport.cpp: the belt-floor check runs before main's PendingNode
queueing.
- Tab.hpp: keep the belt fields, drop the removed upload description
fields.
- tests/libslic3r/CMakeLists.txt: keep both test files.
Also included:
- eSUN PLA belt presets declare their own filament_id (OFkrxQC4) and
scripts/filament_id_snapshot.json is regenerated, as main's filament_id
check requires.
- Custom.json version bumped to 02.04.00.05 so the belt entries reach
existing installs.
- Fix the ambiguous WithinRel call in the belt apron width test, which
otherwise breaks the fff_print build.
Two independent leaks of filament on the belt purge prism, plus the
replan safety net the second one needs.
1. The early-truncation scan bounded itself with the prism's own
toolchanges. ToolOrdering covers the whole print and the prism is a
printed object in it, so the "last toolchange" the scan found was on
the prism's own top layers -- it runs past every model object by
design -- and the truncation cancelled nothing. Bound the scan at the
tallest non-prism object (support layers included; on a belt they can
top the object). On MCTEST5 that was 197 toolchanges over 39.4 mm of
tower that no swap ever needed.
2. On a layer with no toolchange, the prism's entire fill printed as
solid infill in its own filament. Drop the fills no toolchange
claimed, right after the purge marking and before
ensure_perimeters_infills_order() force-overrides whatever is left.
Perimeters stay so the bar keeps a continuous wall. An earlier version
of this deleted the entities and had to be reverted: psWipeTower can
rerun without regenerating infill, and a later tool ordering may claim
what this one did not. The entities are now stashed with their layer,
region and index and put back exactly, the same reversibility contract
layer truncation already had.
3. Both stashes go stale if an object step reruns: make_fills() clears
and regenerates fills over m_layers only, so a stale stash would put
old fills back next to new ones, and truncated layers would keep old
perimeters/fills. Undo the plan's edits at the top of Print::process()
whenever psWipeTower is not done. Every object-step invalidation also
invalidates psWipeTower, so that condition is exactly "some object
step may rerun"; when it is done nothing regenerates and the edits
must stay. This also covers a prism left behind after belt mode is
turned off, which previously stayed truncated forever.
WipingExtrusions::is_entity_overridden() becomes public so the prism can
tell claimed fills from unclaimed ones.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01SsuY8Laiyh7q2zPVVKV3HZ
The preview brim, the placement margin and the pre-generation validation
warning each decided on their own whether the tower has a Type2 cone
base, reading the wall type and cone angle three different ways. The
preview's read cast the preset's enum to ConfigOptionEnum<T>, which a
preset-shaped config never holds, so the cone base was never previewed.
estimate_wipe_tower_first_layer_outline now answers that question once,
beside the footprint estimate, from the config and the resolved planner;
all three sites take the outline from it. The libslic3r case reads the
outline off a preset-shaped config, where the old cast came back empty.
The clamps and validation work from estimates. Once the tower is
generated, _make_wipe_tower re-tests the exact first-layer footprint,
brim and cone base included, against the printable area and the
exclusion zone, so an off-plate tower fails with a clear error instead
of exporting unprintable G-code. The rectangle-wall mesh footprint
learns the Type2 cone base so that check and the post-generation
validation see the real outline.
Pre-generation, validation hard-checks the body plus an explicit brim
and warns on the estimated auto brim and cone base with the existing
"may collide" strings, so the user hears about a marginal position on
the first slice rather than only at generation time.
Two fff_print fixtures that print a tower at the default position move
it onto the 200 mm test bed, as the multifilament fixtures already do:
the shipped default y of 220 is off that bed, and the backstop now says
so instead of exporting the tower.
The shared estimate reserved every tower with one volume-per-purge rule
and the stability floor. Both planners do more: WipeTower (Type1) wipes
each filament's own prime volume in whole lines, one block per
adhesiveness category sized by its worst layer, rams the leaving
filament at every nozzle change, and squares a rib tower from the
planned depth; WipeTower2 (Type2) spaces its lines by
wipe_tower_extra_spacing, not the Type1-only infill gap, and its extra
flow cancels out of the depth. Both extend the ribs rather than the body
below the stability minimum, size every layer including a thinner first
one, and lay the brim in whole loops, WipeTower reporting half a spacing
of line width on top.
All of that now lives in estimate_wipe_tower_footprint, fed the planner
(resolve_wipe_tower_type mirrors Print::wipe_tower_type and the CLI's
Bambu Lab detection) and the filament ids rather than a count. Print
passes its own tool set; the PartPlate adapter derives the plate's ids
from the passed config and treats an explicit count as a floor, so the
CLI's count-only callers size per filament too. The placement clamp also
reserves a Type2 cone's base bulge, which the body box does not cover.
The planner-mirroring helpers sit beside the planners in WipeTower and
WipeTower2 so the two stay in sync; the libslic3r cases pin them to
footprints measured from generated G-code.
Validation grows the estimated body by the brim before the tower is
generated, so a tower whose brim leaves the bed is rejected up front
instead of at export. The scene reload re-clamps the stored position,
since set_default_wipe_tower_pos_for_plate does not rerun when painting
changes the filament count. The rectangle-wall footprint polygon gets its
two missing brim corners (it was a skewed quad), so the post-generation
check covers the whole brim.
A raft is not a reason to reserve a tower. Print::apply runs
normalize_fdm_2, which clears enable_prime_tower for a plate that purges
one filament unless smooth timelapse or wrapping detection is on, so a
single-filament plate with a raft prints no tower at all and the estimate
was reserving bed area for one. Drop the input; need_wipe_tower is now
exactly the two exceptions normalize_fdm_2 honours, named there so the
next reason added has to be checked against it.
The GUI preview and the validation containment check each re-derived
"is a tower printed here" from the filament count instead of reading the
estimate, so both missed the towers printed with no tool change to purge
for. They now take the answer from the footprint, which is the drift this
shared estimate exists to remove. A tower that is not printed estimates to
zero, so its hull is degenerate and every check on it passes trivially -
the containment check needs no gate of its own.
WipeTowerData::width was written only by the pre-generation estimate and
left at zero for the whole post-generation life of the Print, while its
neighbour depth held the real value. Set it from the generator in both
branches.
The plate's height scan transformed every model part's full mesh per
instance on each scene reload, discarding all but the z extent. The
cached convex hull has the same z extent.
A plate loaded from a sliced .gcode.3mf holds no objects and its filaments
live in slice_filaments_info; the config-taking get_extruders overload
returned an empty list for it, which sized the tower for a placeholder two
filaments. It now answers the way the wx overload does, without reaching
the plater.
Also drop estimate_wipe_tower_size, which has no callers.
* build: enable /Zc:lambda for MSVC
MSVC keeps its legacy lambda processor under /std:c++17, which rejects
reading a constexpr constant inside a lambda that does not capture it
(C3493). No other compiler requires that capture, and clang reports it as
an unused one, so the two cannot both be satisfied without the flag.
/Zc:lambda selects the conforming lambda parser that clang and GCC
already use. It is implied by /std:c++20 and /permissive-, so it is only
needed while we are on C++17. clang-cl is conforming already and does not
take the flag.
It requires VS2019 16.8, so build_release_vs.bat now says 16.8+.
* build: clear 237 unused lambda capture warnings
236 captures across 81 files, 142 of them `this`. Removing an unused
capture changes no behavior; clang does not report a capture whose type
has a non-trivial destructor, so nothing held only to extend an object's
lifetime is in this set.
Nine of them are the second half of the warning, "is not required to be
captured for this use", where the capture is a const or constexpr value
the body does read. Those depend on the /Zc:lambda change in the previous
commit. One of them, in FillRectilinear.cpp, had been worked around with
an #ifndef __APPLE__ guard around the capture list, which is now gone.
GUI_ObjectTableSettings.cpp captured its reset button only to read it
inside #ifdef __WXOSX_MAC__. That branch now takes the button from the
event it is already handling.
* build: fail configure on MSVC older than 19.28 instead of dropping /Zc:lambda
cl.exe answers an unrecognized /Zc: sub-option with warning D9002 and keeps
going, so on VS2019 before 16.8 the flag is silently ignored and the build
instead dies with C3493 in FillRectilinear.cpp, nowhere near the cause.
* fix: delete three locals that are now unused
Their only remaining use was the lambda capture this branch removed. The
Clang builds set -Wno-unused-variable, so the build never flagged them.
---------
Co-authored-by: Rodrigo Faselli <162915171+RF47@users.noreply.github.com>
* build: remove std::move that blocks copy elision
std::move wrapped around a temporary, or around a local being returned,
stops the compiler constructing it in place. Each edit is the fix clang
suggests, which is to delete the std::move call and keep its argument.
Three of the 39 sites save a move, the two return std::move(local) in
Print.cpp and TreeSupport.cpp:2749. The rest are equivalent either way
and match how the codebase already writes this elsewhere.
Clears 39 -Wpessimizing-move warnings.
* build: drop null checks on references and this
A reference cannot be bound to null and this cannot be null, so the
compiler folds these conditions to true and drops the guard. Seven are
if (&bitmap && bitmap.IsOk()), where IsOk() already does the work; two
test this directly. The guarded code runs either way, so removing the
dead operand changes nothing.
Clears 11 -Wundefined-bool-conversion warnings.
