Don't emit unexpected cfgs in proc-macros

Author: daxpedda

crates/backend/Cargo.toml

@@ -25,3 +25,6 @@ proc-macro2 = "1.0"
 quote = '1.0'
 syn = { version = '2.0', features = ['full'] }
 wasm-bindgen-shared = { path = "../shared", version = "=0.2.95" }
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(wasm_bindgen_unstable_test_coverage)'] }

crates/backend/src/codegen.rs

@@ -223,6 +223,11 @@ impl ToTokens for ast::Struct {
         let free_fn = Ident::new(&shared::free_function(&name_str), Span::call_site());
         let unwrap_fn = Ident::new(&shared::unwrap_function(&name_str), Span::call_site());
         let wasm_bindgen = &self.wasm_bindgen;
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
         (quote! {
             #[automatically_derived]
             impl #wasm_bindgen::describe::WasmDescribe for #name {
@@ -299,7 +304,7 @@ impl ToTokens for ast::Struct {
                 #[doc(hidden)]
                 // `allow_delayed` is whether it's ok to not actually free the `ptr` immediately
                 // if it's still borrowed.
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 pub unsafe extern "C" fn #free_fn(ptr: u32, allow_delayed: u32) {
                     use #wasm_bindgen::__rt::alloc::rc::Rc;
 
@@ -475,6 +480,11 @@ impl ToTokens for ast::StructField {
             quote! { assert_copy::<#ty>() }
         };
         let maybe_assert_copy = respan(maybe_assert_copy, ty);
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
 
         // Split this out so that it isn't affected by `quote_spanned!`.
         //
@@ -495,7 +505,7 @@ impl ToTokens for ast::StructField {
             const _: () = {
                 #[cfg_attr(all(target_arch = "wasm32", target_os = "unknown"), no_mangle)]
                 #[doc(hidden)]
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 pub unsafe extern "C" fn #getter(js: u32)
                     -> #wasm_bindgen::convert::WasmRet<<#ty as #wasm_bindgen::convert::IntoWasmAbi>::Abi>
                 {
@@ -537,7 +547,7 @@ impl ToTokens for ast::StructField {
             const _: () = {
                 #[no_mangle]
                 #[doc(hidden)]
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 pub unsafe extern "C" fn #setter(
                     js: u32,
                     #(#args,)*
@@ -786,6 +796,12 @@ impl TryToTokens for ast::Export {
             quote! {}
         };
 
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
+
         (quote! {
             #[automatically_derived]
             const _: () = {
@@ -794,7 +810,7 @@ impl TryToTokens for ast::Export {
                     all(target_arch = "wasm32", target_os = "unknown"),
                     export_name = #export_name,
                 )]
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 pub unsafe extern "C" fn #generated_name(#(#args),*) -> #wasm_bindgen::convert::WasmRet<#projection::Abi> {
                     #start_check
 
@@ -1155,6 +1171,12 @@ impl ToTokens for ast::StringEnum {
         let hole = variant_count + 1;
         let attrs = &self.rust_attrs;
 
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
+
         let invalid_to_str_msg = format!(
             "Converting an invalid string enum ({}) back to a string is currently not supported",
             enum_name
@@ -1241,7 +1263,7 @@ impl ToTokens for ast::StringEnum {
 
             #[automatically_derived]
             impl #wasm_bindgen::describe::WasmDescribe for #enum_name {
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 fn describe() {
                     use #wasm_bindgen::describe::*;
                     inform(STRING_ENUM);
@@ -1535,6 +1557,11 @@ impl ToTokens for ast::Enum {
         let name_len = name_str.len() as u32;
         let name_chars = name_str.chars().map(|c| c as u32);
         let hole = &self.hole;
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
         let underlying = if self.signed {
             quote! { i32 }
         } else {
@@ -1587,7 +1614,7 @@ impl ToTokens for ast::Enum {
 
             #[automatically_derived]
             impl #wasm_bindgen::describe::WasmDescribe for #enum_name {
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 fn describe() {
                     use #wasm_bindgen::describe::*;
                     inform(ENUM);
@@ -1813,6 +1840,12 @@ impl<'a, T: ToTokens> ToTokens for Descriptor<'a, T> {
             return;
         }
 
+        let maybe_no_coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+            Some(quote! { #[coverage(off)] })
+        } else {
+            None
+        };
+
         let name = Ident::new(&format!("__wbindgen_describe_{}", ident), ident.span());
         let inner = &self.inner;
         let attrs = &self.attrs;
@@ -1824,7 +1857,7 @@ impl<'a, T: ToTokens> ToTokens for Descriptor<'a, T> {
                 #(#attrs)*
                 #[no_mangle]
                 #[doc(hidden)]
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #maybe_no_coverage
                 pub extern "C" fn #name() {
                     use #wasm_bindgen::describe::*;
                     // See definition of `link_mem_intrinsics` for what this is doing

crates/test-macro/src/lib.rs

@@ -109,12 +109,17 @@ pub fn wasm_bindgen_test(
     // main test harness. This is the entry point for all tests.
     let name = format_ident!("__wbgt_{}_{}", ident, CNT.fetch_add(1, Ordering::SeqCst));
     let wasm_bindgen_path = attributes.wasm_bindgen_path;
+    let coverage = if cfg!(wasm_bindgen_unstable_test_coverage) {
+        Some(quote! { #[coverage(off)] })
+    } else {
+        None
+    };
     tokens.extend(
         quote! {
             const _: () = {
                 #[no_mangle]
                 #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
-                #[cfg_attr(wasm_bindgen_unstable_test_coverage, coverage(off))]
+                #coverage
                 pub extern "C" fn #name(cx: &#wasm_bindgen_path::__rt::Context) {
                     let test_name = ::core::concat!(::core::module_path!(), "::", ::core::stringify!(#ident));
                     #test_body