use the AST pretty printer (crate rustc_ast_pretty), rustc_ast_pretty::pprust::attribute_to_string to figure the full no_mangle attribute for the error message

Author: sassman

Cargo.lock

@@ -3442,6 +3442,7 @@ dependencies = [
  "rustc_abi",
  "rustc_arena",
  "rustc_ast",
+ "rustc_ast_pretty",
  "rustc_attr",
  "rustc_data_structures",
  "rustc_errors",

compiler/rustc_codegen_ssa/Cargo.toml

@@ -17,6 +17,7 @@ regex = "1.4"
 rustc_abi = { path = "../rustc_abi" }
 rustc_arena = { path = "../rustc_arena" }
 rustc_ast = { path = "../rustc_ast" }
+rustc_ast_pretty = { path = "../rustc_ast_pretty" }
 rustc_attr = { path = "../rustc_attr" }
 rustc_data_structures = { path = "../rustc_data_structures" }
 rustc_errors = { path = "../rustc_errors" }
@@ -54,8 +55,18 @@ libc = "0.2.50"
 [dependencies.object]
 version = "0.36.2"
 default-features = false
-features = ["read_core", "elf", "macho", "pe", "xcoff", "unaligned", "archive", "write", "wasm"]
+features = [
+    "read_core",
+    "elf",
+    "macho",
+    "pe",
+    "xcoff",
+    "unaligned",
+    "archive",
+    "write",
+    "wasm",
+]
 
 [target.'cfg(windows)'.dependencies.windows]
 version = "0.57.0"
-features = ["Win32_Globalization"]
+features = ["Win32_Globalization"]

compiler/rustc_codegen_ssa/messages.ftl

@@ -190,10 +190,10 @@ codegen_ssa_missing_memory_ordering = Atomic intrinsic missing memory ordering
 codegen_ssa_missing_query_depgraph =
     found CGU-reuse attribute but `-Zquery-dep-graph` was not specified
 
-codegen_ssa_mixed_export_name_and_no_mangle = the `#[{$no_mangle_attr_name}]` attribute may not be used in combination with `#[export_name]`
-    .label = `#[{$no_mangle_attr_name}]` is ignored
+codegen_ssa_mixed_export_name_and_no_mangle = the `{$no_mangle_attr_name}` attribute may not be used in combination with `#[export_name]`
+    .label = `{$no_mangle_attr_name}` is ignored
     .note = `#[export_name]` takes precedence
-    .suggestion = remove the `#[{$no_mangle_attr_name}]` attribute
+    .suggestion = remove the `{$no_mangle_attr_name}` attribute
 
 codegen_ssa_msvc_missing_linker = the msvc targets depend on the msvc linker but `link.exe` was not found
 

compiler/rustc_codegen_ssa/src/codegen_attrs.rs

@@ -120,7 +120,7 @@ fn codegen_fn_attrs(tcx: TyCtxt<'_>, did: LocalDefId) -> CodegenFnAttrs {
                     mixed_export_name_no_mangle_lint_state.track_no_mangle(
                         attr.span,
                         tcx.local_def_id_to_hir_id(did),
-                        name.to_ident_string().into(),
+                        rustc_ast_pretty::pprust::attribute_to_string(attr),
                     );
                 } else {
                     tcx.dcx()

tests/ui/attributes/mixed_export_name_and_no_mangle.fixed

@@ -3,13 +3,12 @@
 //@ check-pass
 
 #![warn(unused_attributes)]
-//~^ WARN the `#[no_mangle]` attribute may not be used in combination with `#[export_name]`
+//~^ WARN the `#[no_mangle]` attribute may not be used in combination with `#[export_name]` [unused_attributes]
 #[export_name = "foo"]
 pub fn bar() {}
 
-//~^ WARN the `#[unsafe(no_mangle)]` attribute may not be used in combination with `#[export_name]`
+//~^ WARN the `#[unsafe(no_mangle)]` attribute may not be used in combination with `#[export_name]` [unused_attributes]
 #[export_name = "baz"]
 pub fn bak() {}
 
-
 fn main() {}

tests/ui/attributes/mixed_export_name_and_no_mangle.rs

@@ -4,14 +4,13 @@
 
 #![warn(unused_attributes)]
 #[no_mangle]
-//~^ WARN the `#[no_mangle]` attribute may not be used in combination with `#[export_name]`
+//~^ WARN the `#[no_mangle]` attribute may not be used in combination with `#[export_name]` [unused_attributes]
 #[export_name = "foo"]
 pub fn bar() {}
 
 #[unsafe(no_mangle)]
-//~^ WARN the `#[unsafe(no_mangle)]` attribute may not be used in combination with `#[export_name]`
+//~^ WARN the `#[unsafe(no_mangle)]` attribute may not be used in combination with `#[export_name]` [unused_attributes]
 #[export_name = "baz"]
 pub fn bak() {}
 
-
 fn main() {}

tests/ui/attributes/mixed_export_name_and_no_mangle.stderr

@@ -19,20 +19,21 @@ help: remove the `#[no_mangle]` attribute
 LL - #[no_mangle]
    |
 
-warning: the `#[unsafe(no_mangle)]` attribute may not be used in combination with `#[export_name]`
+warning: the `#[no_mangle]` attribute may not be used in combination with `#[export_name]`
   --> $DIR/mixed_export_name_and_no_mangle.rs:11:1
    |
 LL | #[unsafe(no_mangle)]
-   | ^^^^^^^^^^^^^^^^^^^^ #[unsafe(no_mangle)]` is ignored
+   | ^^^^^^^^^^^^^^^^^^^^ `#[no_mangle]` is ignored
    |
 note: `#[export_name]` takes precedence
   --> $DIR/mixed_export_name_and_no_mangle.rs:13:1
    |
 LL | #[export_name = "baz"]
    | ^^^^^^^^^^^^^^^^^^^^^^
-help: remove the #[unsafe(no_mangle)]` attribute
+help: remove the `#[no_mangle]` attribute
    |
 LL - #[unsafe(no_mangle)]
    |
 
 warning: 2 warnings emitted
+