From a809ec96f3cf5f5a73db24129392e64c8285bda8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E8=AE=B8=E6=9D=B0=E5=8F=8B=20Jieyou=20Xu=20=28Joe=29?=
 <jieyouxu@outlook.com>
Date: Mon, 8 Apr 2024 21:18:51 +0000
Subject: [PATCH] test: check that `?` suggestion has local span

This can cause rustfix to crash because the `?` suggestion previously
could point into non-local spans, such as into the stdlib.
---
 .../question-mark-operator-suggestion-span.rs | 22 +++++++++++++
 ...stion-mark-operator-suggestion-span.stderr | 31 +++++++++++++++++++
 2 files changed, 53 insertions(+)
 create mode 100644 tests/ui/typeck/question-mark-operator-suggestion-span.rs
 create mode 100644 tests/ui/typeck/question-mark-operator-suggestion-span.stderr

diff --git a/tests/ui/typeck/question-mark-operator-suggestion-span.rs b/tests/ui/typeck/question-mark-operator-suggestion-span.rs
new file mode 100644
index 00000000000..7aea6e63dd1
--- /dev/null
+++ b/tests/ui/typeck/question-mark-operator-suggestion-span.rs
@@ -0,0 +1,22 @@
+// Check that we don't construct a span for `?` suggestions that point into non-local macros
+// like into the stdlib where the user has no control over.
+//
+// FIXME(jieyouxu): this test is currently NOT run-rustfix because there are conflicting
+// MaybeIncorrect suggestions:
+//
+// 1. adding `return ... ;`, and
+// 2. adding `?`.
+//
+// When rustfix puts those together, the fixed file now contains uncompilable code.
+
+#![crate_type = "lib"]
+
+pub fn bug_report<W: std::fmt::Write>(w: &mut W) -> std::fmt::Result {
+    if true {
+        writeln!(w, "`;?` here ->")?;
+    } else {
+        writeln!(w, "but not here")
+        //~^ ERROR mismatched types
+    }
+    Ok(())
+}
diff --git a/tests/ui/typeck/question-mark-operator-suggestion-span.stderr b/tests/ui/typeck/question-mark-operator-suggestion-span.stderr
new file mode 100644
index 00000000000..089b3bcd198
--- /dev/null
+++ b/tests/ui/typeck/question-mark-operator-suggestion-span.stderr
@@ -0,0 +1,31 @@
+error[E0308]: mismatched types
+  --> $DIR/question-mark-operator-suggestion-span.rs:18:9
+   |
+LL | /     if true {
+LL | |         writeln!(w, "`;?` here ->")?;
+LL | |     } else {
+LL | |         writeln!(w, "but not here")
+   | |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `()`, found `Result<(), Error>`
+LL | |
+LL | |     }
+   | |_____- expected this to be `()`
+   |
+   = note: expected unit type `()`
+                   found enum `Result<(), std::fmt::Error>`
+   = note: this error originates in the macro `writeln` (in Nightly builds, run with -Z macro-backtrace for more info)
+help: consider using a semicolon here
+   |
+LL |     };
+   |      +
+help: you might have meant to return this value
+   |
+LL |         return writeln!(w, "but not here");
+   |         ++++++                            +
+help: use the `?` operator to extract the `Result<(), std::fmt::Error>` value, propagating a `Result::Err` value to the caller
+   |
+LL |         writeln!(w, "but not here")?
+   |                                    +
+
+error: aborting due to 1 previous error
+
+For more information about this error, try `rustc --explain E0308`.