Add Utility Trait to Convert from u32 to usize

[florianhartung]

Because Wasm uses u32s for indexing and Rust uses usizes, we have to convert a lot of u32s to usizes.

In Rust it is generally not recommended to use the as keyword to cast between numerical types, because they might result in unexpected errors, imprecision or other unexpected sign extension behaviors. Normally, the From/Into traits should be used instead. However Rust does not provide a From<u32> for usize implementation.

Therefore, this PR adds a new utility trait to convert from a u32 to a usize.

While we might want to support targets with a 16 bit pointer width in the future, this is a small and easy solution for now.

Checks

• Using Nix
  • Ran nix fmt
  • Ran nix flake check '.?submodules=1'
• Using Rust tooling
  • Ran cargo fmt
  • Ran cargo test
  • Ran cargo check
  • Ran cargo build
  • Ran cargo doc

[codecov]

Codecov Report

❌ Patch coverage is 78.48837% with 37 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/validation/code.rs	26.82%	0 Missing and 30 partials ⚠️
src/execution/store/mod.rs	71.42%	2 Missing ⚠️
src/validation/read_constant_expression.rs	0.00%	0 Missing and 2 partials ⚠️
src/core/reader/types/mod.rs	50.00%	0 Missing and 1 partial ⚠️
src/validation/data.rs	0.00%	0 Missing and 1 partial ⚠️
src/validation/mod.rs	66.66%	0 Missing and 1 partial ⚠️

Files with missing lines	Coverage Δ
src/core/reader/section_header.rs	96.29% <100.00%> (ø)
src/core/reader/types/element.rs	87.61% <100.00%> (ø)
src/core/reader/types/export.rs	40.00% <100.00%> (ø)
src/core/reader/types/import.rs	90.32% <100.00%> (ø)
src/core/reader/types/values.rs	73.83% <100.00%> (ø)
src/core/rw_spinlock.rs	90.76% <100.00%> (ø)
src/core/utils.rs	100.00% <100.00%> (ø)
src/execution/const_interpreter_loop.rs	76.25% <100.00%> (ø)
src/execution/interpreter_loop.rs	76.32% <100.00%> (+0.04%)	⬆️
src/execution/store/instances.rs	84.90% <100.00%> (ø)
... and 8 more

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[github-actions]

PR Preview Action v1.4.7
Preview removed because the pull request was closed.
2026-02-18 14:51 UTC