From 504acf876035fa2b944c64d01f6fe66b30acf1e4 Mon Sep 17 00:00:00 2001
From: Martin Nordholts <enselic@gmail.com>
Date: Mon, 24 Jul 2023 14:40:44 +0200
Subject: [PATCH] Make `--error-format human-annotate-rs` handle multiple files

---
 .../src/annotate_snippet_emitter_writer.rs    | 20 ++++++++++++-------
 .../annotate-snippet/auxiliary/other_file.rs  |  6 ++++++
 tests/ui/annotate-snippet/multiple-files.rs   |  8 ++++++++
 .../ui/annotate-snippet/multiple-files.stderr | 11 ++++++++++
 4 files changed, 38 insertions(+), 7 deletions(-)
 create mode 100644 tests/ui/annotate-snippet/auxiliary/other_file.rs
 create mode 100644 tests/ui/annotate-snippet/multiple-files.rs
 create mode 100644 tests/ui/annotate-snippet/multiple-files.stderr

diff --git a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
index 9872b3bda1e..a88fba6dae6 100644
--- a/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
+++ b/compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs
@@ -157,10 +157,8 @@ fn emit_messages_default(
             {
                 annotated_files.swap(0, pos);
             }
-            // owned: line source, line index, annotations
-            type Owned = (String, usize, Vec<crate::snippet::Annotation>);
-            let filename = source_map.filename_for_diagnostics(&primary_lo.file.name);
-            let origin = filename.to_string_lossy();
+            // owned: file name, line source, line index, annotations
+            type Owned = (String, String, usize, Vec<crate::snippet::Annotation>);
             let annotated_files: Vec<Owned> = annotated_files
                 .into_iter()
                 .flat_map(|annotated_file| {
@@ -169,7 +167,15 @@ fn emit_messages_default(
                         .lines
                         .into_iter()
                         .map(|line| {
-                            (source_string(file.clone(), &line), line.line_index, line.annotations)
+                            // Ensure the source file is present before we try
+                            // to load a string from it.
+                            source_map.ensure_source_file_source_present(file.clone());
+                            (
+                                format!("{}", source_map.filename_for_diagnostics(&file.name)),
+                                source_string(file.clone(), &line),
+                                line.line_index,
+                                line.annotations,
+                            )
                         })
                         .collect::<Vec<Owned>>()
                 })
@@ -192,11 +198,11 @@ fn emit_messages_default(
                 },
                 slices: annotated_files
                     .iter()
-                    .map(|(source, line_index, annotations)| {
+                    .map(|(file_name, source, line_index, annotations)| {
                         Slice {
                             source,
                             line_start: *line_index,
-                            origin: Some(&origin),
+                            origin: Some(&file_name),
                             // FIXME(#59346): Not really sure when `fold` should be true or false
                             fold: false,
                             annotations: annotations
diff --git a/tests/ui/annotate-snippet/auxiliary/other_file.rs b/tests/ui/annotate-snippet/auxiliary/other_file.rs
new file mode 100644
index 00000000000..6f5f412d086
--- /dev/null
+++ b/tests/ui/annotate-snippet/auxiliary/other_file.rs
@@ -0,0 +1,6 @@
+pub struct WithPrivateMethod;
+
+impl WithPrivateMethod {
+    /// Private to get an error involving two files
+    fn private_method(&self) {}
+}
diff --git a/tests/ui/annotate-snippet/multiple-files.rs b/tests/ui/annotate-snippet/multiple-files.rs
new file mode 100644
index 00000000000..981cdbb10a9
--- /dev/null
+++ b/tests/ui/annotate-snippet/multiple-files.rs
@@ -0,0 +1,8 @@
+// aux-build:other_file.rs
+// compile-flags: --error-format human-annotate-rs -Z unstable-options
+
+extern crate other_file;
+
+fn main() {
+    other_file::WithPrivateMethod.private_method();
+}
diff --git a/tests/ui/annotate-snippet/multiple-files.stderr b/tests/ui/annotate-snippet/multiple-files.stderr
new file mode 100644
index 00000000000..4236ec811d0
--- /dev/null
+++ b/tests/ui/annotate-snippet/multiple-files.stderr
@@ -0,0 +1,11 @@
+error[E0624]: method `private_method` is private
+  --> $DIR/multiple-files.rs:7:35
+   |
+LL |     other_file::WithPrivateMethod.private_method();
+   |                                   ^^^^^^^^^^^^^^ private method
+   |
+  ::: $DIR/auxiliary/other_file.rs:5:5
+   |
+LL |     fn private_method(&self) {}
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^ private method defined here
+   |