warn on deprecated itemlist imports

Cargo.toml

@@ -8,11 +8,12 @@ repository = "https://github.com/bevyengine/naga_oil/"
 readme = "README.md"
 
 [features]
-default = ["test_shader"]
+default = ["test_shader", "warn_deprecated"]
 # enable tests that need a graphical card
 test_shader = []
 prune = []
 override_any = []
+warn_deprecated = []
 
 [dependencies]
 naga = { version = "0.13", features = ["wgsl-in", "wgsl-out", "glsl-in", "glsl-out", "clone", "span"] }

src/compose/parse_imports.rs

@@ -1,5 +1,7 @@
 use std::collections::HashMap;
 
+use tracing::warn;
+
 use super::{
     tokenizer::{Token, Tokenizer},
     Composer, ImportDefWithOffset, ImportDefinition,
@@ -44,6 +46,9 @@ pub fn parse_imports<'a>(
 
                 // support deprecated #import mod item
                 if let Some(Token::Identifier(..)) = tokens.peek() {
+                    #[cfg(feature="warn_deprecated")]
+                    warn!("item list imports are deprecated, please use `rust::style::item_imports;`\n| {}", input);
+
                     is_deprecated_itemlist = true;
                     stack.push(format!("{}::", current));
                     current = String::default();