From dca52ac835f8c87dfc3167606d1146ce6b9bba11 Mon Sep 17 00:00:00 2001
From: Tshepang Mbambo <tshepang@gmail.com>
Date: Fri, 24 Feb 2023 23:37:10 +0200
Subject: [PATCH] make "proc macro panicked" translatable

---
 compiler/rustc_expand/locales/en-US.ftl |  4 ++++
 compiler/rustc_expand/src/errors.rs     | 15 +++++++++++++++
 compiler/rustc_expand/src/proc_macro.rs | 12 +++++++-----
 3 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/compiler/rustc_expand/locales/en-US.ftl b/compiler/rustc_expand/locales/en-US.ftl
index dbd80954382db..b475d285f6b7e 100644
--- a/compiler/rustc_expand/locales/en-US.ftl
+++ b/compiler/rustc_expand/locales/en-US.ftl
@@ -129,3 +129,7 @@ expand_module_multiple_candidates =
     .help = delete or rename one of them to remove the ambiguity
 
 expand_trace_macro = trace_macro
+
+expand_proc_macro_panicked =
+    proc macro panicked
+    .help = message: {$message}
diff --git a/compiler/rustc_expand/src/errors.rs b/compiler/rustc_expand/src/errors.rs
index d9b2b5f4802c8..70ab222b48470 100644
--- a/compiler/rustc_expand/src/errors.rs
+++ b/compiler/rustc_expand/src/errors.rs
@@ -375,3 +375,18 @@ pub struct TraceMacro {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(expand_proc_macro_panicked)]
+pub(crate) struct ProcMacroPanicked {
+    #[primary_span]
+    pub span: Span,
+    #[subdiagnostic]
+    pub message: Option<ProcMacroPanickedHelp>,
+}
+
+#[derive(Subdiagnostic)]
+#[help(expand_help)]
+pub(crate) struct ProcMacroPanickedHelp {
+    pub message: String,
+}
diff --git a/compiler/rustc_expand/src/proc_macro.rs b/compiler/rustc_expand/src/proc_macro.rs
index e9a6919206894..cef64a1047902 100644
--- a/compiler/rustc_expand/src/proc_macro.rs
+++ b/compiler/rustc_expand/src/proc_macro.rs
@@ -1,4 +1,5 @@
 use crate::base::{self, *};
+use crate::errors;
 use crate::proc_macro_server;
 
 use rustc_ast as ast;
@@ -60,11 +61,12 @@ impl base::BangProcMacro for BangProcMacro {
         let strategy = exec_strategy(ecx);
         let server = proc_macro_server::Rustc::new(ecx);
         self.client.run(&strategy, server, input, proc_macro_backtrace).map_err(|e| {
-            let mut err = ecx.struct_span_err(span, "proc macro panicked");
-            if let Some(s) = e.as_str() {
-                err.help(&format!("message: {}", s));
-            }
-            err.emit()
+            ecx.sess.emit_err(errors::ProcMacroPanicked {
+                span,
+                message: e
+                    .as_str()
+                    .map(|message| errors::ProcMacroPanickedHelp { message: message.into() }),
+            })
         })
     }
 }