[vello_shaders] Use thiserror::Error for the library Error type

vello_shaders/Cargo.toml

@@ -5,13 +5,15 @@ edition = "2021"
 
 [features]
 default = ["compile", "wgsl", "msl"]
-compile = ["naga"]
+compile = ["naga", "thiserror"]
 wgsl = []
 msl = []
 
 [dependencies]
 naga = { git = "https://github.com/gfx-rs/naga", features = ["wgsl-in", "msl-out", "validate"], optional = true }
+thiserror = { version = "1.0.40", optional = true }
 
 [build-dependencies]
 naga = { git = "https://github.com/gfx-rs/naga", features = ["wgsl-in", "msl-out", "validate"] }
+thiserror = "1.0.40"
 

vello_shaders/src/compile/mod.rs

@@ -1,12 +1,14 @@
-use naga::{
+use {
+    naga::{
         front::wgsl,
         valid::{Capabilities, ModuleInfo, ValidationError, ValidationFlags},
         AddressSpace, ImageClass, Module, StorageAccess, WithSpan,
-};
+    },
-
+    std::{
-use std::{
         collections::{HashMap, HashSet},
         path::Path,
+    },
+    thiserror::Error,
 };
 
 pub mod permutations;
@@ -16,25 +18,18 @@ pub mod msl;
 
 use crate::types::{BindType, BindingInfo};
 
-#[derive(Debug)]
+#[derive(Error, Debug)]
 pub enum Error {
-    Parse(wgsl::ParseError),
+    #[error("failed to parse shader: {0}")]
-    Validate(WithSpan<ValidationError>),
+    Parse(#[from] wgsl::ParseError),
+
+    #[error("failed to validate shader: {0}")]
+    Validate(#[from] WithSpan<ValidationError>),
+
+    #[error("missing entry point function")]
     EntryPointNotFound,
 }
 
-impl From<wgsl::ParseError> for Error {
-    fn from(e: wgsl::ParseError) -> Self {
-        Self::Parse(e)
-    }
-}
-
-impl From<WithSpan<ValidationError>> for Error {
-    fn from(e: WithSpan<ValidationError>) -> Self {
-        Self::Validate(e)
-    }
-}
-
 #[derive(Debug)]
 pub struct ShaderInfo {
     pub source: String,