Make naga span methods take path as generic AsRef Path

CHANGELOG.md

@@ -54,6 +54,7 @@ Bottom level categories:
 #### Naga
 
 - When emitting GLSL, Uniform and Storage Buffer memory layouts are now emitted even if no explicit binding is given. By @cloone8 in [#7579](https://github.com/gfx-rs/wgpu/pull/7579).
+- Diagnostic rendering methods (i.e., `naga::{front::wgsl::ParseError,WithSpan}::emit_error_to_string_with_path`) now accept more types for their `path` argument via a new sealed `AsDiagnosticFilePath` trait. By @atlv24 and @ErichDonGubler in [#7643](https://github.com/gfx-rs/wgpu/pull/7643).
 
 ### Bug Fixes
 

naga/Cargo.toml

@@ -23,6 +23,7 @@ default = []
 dot-out = []
 glsl-in = ["dep:pp-rs"]
 glsl-out = []
+std = []
 
 ## Enables outputting to the Metal Shading Language (MSL).
 ##

naga/src/as_diagnostic_file_path.rs

@@ -0,0 +1,76 @@
+//! [`AsDiagnosticFilePath`] and its supporting items.
+
+use alloc::borrow::Cow;
+
+#[cfg(feature = "std")]
+use std::path::Path;
+
+#[cfg(not(feature = "std"))]
+use alloc::string::String;
+
+mod sealed {
+    pub trait Sealed {}
+}
+
+/// A trait that abstracts over types accepted for conversion to the most
+/// featureful path representation possible; that is:
+///
+/// - When `no_std` is active, this represents types can be converted to `Cow<'_, str>`.
+/// - Otherwise, types that implement `AsRef<Path>` (to extract a `&Path`).
+///
+/// This type is used as the type bounds for various diagnostic rendering methods, i.e.,
+/// [`WithSpan::emit_to_string_with_path`](crate::span::WithSpan::emit_to_string_with_path).
+pub trait AsDiagnosticFilePath: sealed::Sealed {
+    fn to_string_lossy(&self) -> Cow<'_, str>;
+}
+
+#[cfg(feature = "std")]
+impl<T: AsRef<Path> + ?Sized> AsDiagnosticFilePath for T {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        self.as_ref().to_string_lossy()
+    }
+}
+
+#[cfg(feature = "std")]
+impl<T: AsRef<Path> + ?Sized> sealed::Sealed for T {}
+
+#[cfg(not(feature = "std"))]
+impl AsDiagnosticFilePath for String {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self.as_str())
+    }
+}
+
+#[cfg(not(feature = "std"))]
+impl sealed::Sealed for String {}
+
+#[cfg(not(feature = "std"))]
+impl AsDiagnosticFilePath for str {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        Cow::Borrowed(self)
+    }
+}
+
+#[cfg(not(feature = "std"))]
+impl sealed::Sealed for str {}
+
+#[cfg(not(feature = "std"))]
+impl AsDiagnosticFilePath for Cow<'_, str> {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        use core::borrow::Borrow;
+        Cow::Borrowed(self.borrow())
+    }
+}
+
+#[cfg(not(feature = "std"))]
+impl sealed::Sealed for Cow<'_, str> {}
+
+#[cfg(not(feature = "std"))]
+impl<T: AsDiagnosticFilePath + ?Sized> AsDiagnosticFilePath for &T {
+    fn to_string_lossy(&self) -> Cow<'_, str> {
+        (*self).to_string_lossy()
+    }
+}
+
+#[cfg(not(feature = "std"))]
+impl<T: AsDiagnosticFilePath + ?Sized> sealed::Sealed for &T {}

naga/src/lib.rs

@@ -106,6 +106,7 @@ extern crate std;
 extern crate alloc;
 
 mod arena;
+mod as_diagnostic_file_path;
 pub mod back;
 pub mod common;
 #[cfg(feature = "compact")]

naga/src/span.rs

@@ -6,7 +6,7 @@ use alloc::{
 };
 use core::{error::Error, fmt, ops::Range};
 
-use crate::{Arena, Handle, UniqueArena};
+use crate::{as_diagnostic_file_path::AsDiagnosticFilePath, Arena, Handle, UniqueArena};
 
 /// A source code span, used for error reporting.
 #[derive(Clone, Copy, Debug, PartialEq, Default)]
@@ -283,12 +283,14 @@ impl<E> WithSpan<E> {
 
     /// Emits a summary of the error to standard error stream.
     #[cfg(feature = "stderr")]
-    pub fn emit_to_stderr_with_path(&self, source: &str, path: &str)
+    pub fn emit_to_stderr_with_path<P>(&self, source: &str, path: P)
     where
         E: Error,
+        P: AsDiagnosticFilePath,
     {
         use codespan_reporting::{files, term};
 
+        let path = path.to_string_lossy();
         let files = files::SimpleFile::new(path, source);
         let config = term::Config::default();
 
@@ -313,12 +315,14 @@ impl<E> WithSpan<E> {
     }
 
     /// Emits a summary of the error to a string.
-    pub fn emit_to_string_with_path(&self, source: &str, path: &str) -> String
+    pub fn emit_to_string_with_path<P>(&self, source: &str, path: P) -> String
     where
         E: Error,
+        P: AsDiagnosticFilePath,
     {
         use codespan_reporting::{files, term};
 
+        let path = path.to_string_lossy();
         let files = files::SimpleFile::new(path, source);
         let config = term::Config::default();