From 2e81955d9cf6660585d9567792f79d9214c1d293 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sun, 23 Mar 2025 15:50:51 +0300
Subject: [PATCH 1/2] compiletest: Support matching on diagnostics without a
 span

---
 src/tests/ui.md | 26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)

diff --git a/src/tests/ui.md b/src/tests/ui.md
index c8536b00..98bb9dee 100644
--- a/src/tests/ui.md
+++ b/src/tests/ui.md
@@ -202,6 +202,9 @@ several ways to match the message with the line (see the examples below):
 * `~|`: Associates the error level and message with the *same* line as the
   *previous comment*. This is more convenient than using multiple carets when
   there are multiple messages associated with the same line.
+* `~?`: Used to match error levels and messages with errors not having line
+  information. These can be placed on any line in the test file, but are
+  conventionally placed at the end.
 
 Example:
 
@@ -270,10 +273,23 @@ fn main() {
 //~| ERROR this pattern has 1 field, but the corresponding tuple struct has 3 fields [E0023]
 ```
 
+#### Error without line information
+
+Use `//~?` to match an error without line information.
+`//~?` is precise and will not match errors if their line information is available.
+It should be preferred to using `error-pattern`, which is imprecise and non-exhaustive.
+
+```rust,ignore
+//@ compile-flags: --print yyyy
+
+//~? ERROR unknown print request: `yyyy`
+```
+
 ### `error-pattern`
 
-The `error-pattern` [directive](directives.md) can be used for messages that don't
-have a specific span.
+The `error-pattern` [directive](directives.md) can be used for runtime messages, which don't
+have a specific span, or for compile time messages if imprecise matching is required due to
+multi-line platform specific diagnostics.
 
 Let's think about this test:
 
@@ -300,7 +316,9 @@ fn main() {
 }
 ```
 
-But for strict testing, try to use the `ERROR` annotation as much as possible.
+But for strict testing, try to use the `ERROR` annotation as much as possible,
+including `//~?` annotations for diagnostics without span.
+For compile time diagnostics `error-pattern` should very rarely be necessary.
 
 ### Error levels
 
@@ -353,7 +371,7 @@ would be a `.mir.stderr` and `.thir.stderr` file with the different outputs of
 the different revisions.
 
 > Note: cfg revisions also work inside the source code with `#[cfg]` attributes.
-> 
+>
 > By convention, the `FALSE` cfg is used to have an always-false config.
 
 ## Controlling pass/fail expectations

From 628eb7064d7aaea62521e11d6cc6b7306f51c248 Mon Sep 17 00:00:00 2001
From: Vadim Petrochenkov <vadim.petrochenkov@gmail.com>
Date: Sat, 29 Mar 2025 12:52:10 +0300
Subject: [PATCH 2/2] compiletest: Support matching diagnostics on lines below

---
 src/tests/ui.md | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/tests/ui.md b/src/tests/ui.md
index 98bb9dee..1190c264 100644
--- a/src/tests/ui.md
+++ b/src/tests/ui.md
@@ -202,6 +202,9 @@ several ways to match the message with the line (see the examples below):
 * `~|`: Associates the error level and message with the *same* line as the
   *previous comment*. This is more convenient than using multiple carets when
   there are multiple messages associated with the same line.
+* `~v`: Associates the error level and message with the *next* error
+  annotation line. Each symbol (`v`) that you add adds a line to this, so `~vvv`
+  is three lines below the error annotation line.
 * `~?`: Used to match error levels and messages with errors not having line
   information. These can be placed on any line in the test file, but are
   conventionally placed at the end.
@@ -273,6 +276,18 @@ fn main() {
 //~| ERROR this pattern has 1 field, but the corresponding tuple struct has 3 fields [E0023]
 ```
 
+#### Positioned above error line
+
+Use the `//~v` idiom with number of v's in the string to indicate the number
+of lines below. This is typically used in lexer or parser tests matching on errors like unclosed
+delimiter or unclosed literal happening at the end of file.
+
+```rust,ignore
+// ignore-tidy-trailing-newlines
+//~v ERROR this file contains an unclosed delimiter
+fn main((ؼ
+```
+
 #### Error without line information
 
 Use `//~?` to match an error without line information.