A braced initialiser does not allow a narrowing conversion unless the value
is a constant expression the compiler can prove fits. Every site here holds a
runtime value: WORLD_COLS is the global guiWorldCols, the laptop screen
coordinates are built from iScreenWidthOffset, the sector limits come from the
externalised options. MSVC accepts all of it silently; clang rejects it, and
it is ill-formed.
Nothing about the generated code changes. MSVC was already performing these
conversions; the casts only say so out loud, at the 73 places where it was
happening implicitly.
The invariant: each site is wrapped in a static_cast to the element type the
initialiser already had, and nothing else is touched. No type is widened, no
expression is reassociated, no value is clamped or checked. static_cast rather
than a C-style cast so that a later reader can grep for the narrowings, and so
that none of these can quietly become a reinterpret_cast if a type changes.
Verification:
# every changed line differs only by inserted casts and their parentheses
git show HEAD -U0 | grep '^[+-][^+-]' |
sed -E 's/static_cast<[A-Za-z0-9_]+>//g; s/[()]//g; s/^[+-]//' |
sort | uniq -c | awk '$1 % 2' # no output
git show HEAD -U0 | grep -c '^+[^+]' # 38 lines, 73 casts
ninja -C build parse # narrowing class gone: 129 -> 91 sites
ninja -C build -k 0 # Release, four applications, green
ninja -C build-debug -k 0 # Debug, four applications, green
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
BeatAroundTheBuscherandGitHub
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