Runtime Validation

In addition to the auto-generated cargo test checks, wgsl-rs exposes runtime validation APIs that let you validate shader source on demand — useful for instantiated templates, dynamically composed pipelines, and CI scripts that want to fail fast on bad WGSL.

WGSL_SOURCE.validate()

Every #[wgsl] module exposes a pub static WGSL_SOURCE: &str containing the transpiled WGSL. When the validation feature is enabled, calling .validate() on it runs naga and returns a Result:

#![allow(unused)]
fn main() {
use example::hello_triangle::WGSL_SOURCE;

WGSL_SOURCE.validate().expect("hello_triangle failed validation");
}

This is exactly what the auto-generated __validate_wgsl test calls. See Auto-generated Tests.

module.validate()

For template modules you instantiate at runtime, the returned ir::Module also has a .validate() method (with the validation feature):

#![allow(unused)]
fn main() {
use example::hello_triangle_generic as tmpl;
use wgsl_rs::ir;

let module: ir::Module = tmpl::instantiate::<f32, f32>();
module.validate().expect("instantiated template failed validation");
let source: String = module.to_wgsl();
}

module.validate() runs naga over the substituted, concrete WGSL — the same path the validate_with_instantiation_types attribute uses at test time, but driven from your own code.

validate_with_instantiation_types at Runtime

The validate_with_instantiation_types(T1, T2, ...) helper is also callable as a runtime function on a template module:

#![allow(unused)]
fn main() {
use example::hello_triangle_generic as tmpl;

tmpl::validate_with_instantiation_types(f32, f32)
    .expect("template validation failed");
}

This is convenient when you want to validate several instantiations of the same template from a single test or application entry point. The argument list mirrors the template's declared type parameters.

The validation Feature

Both WGSL_SOURCE.validate() and module.validate() require the validation feature on the wgsl-rs crate. It is enabled by default. If you turn it off (see Disabling Validation), those methods are removed and any call site will fail to compile — there is no stub that silently returns Ok.

Error Reporting

Validation errors surface naga's diagnostics directly. A typical failure looks like:

WGSL validation failed: SomeWrongSnafu { ... }
  in module `hello_triangle`
  at @vertex fn vtx_main(...)

The error includes the offending module name (or the instantiated template's type arguments) and the naga span where available. For template modules, validate after instantiation so the error points at concrete WGSL rather than TypeParam placeholders.