From 6a834b4df8a45fafea84761b6e25ccdf75cec007 Mon Sep 17 00:00:00 2001
From: Jubilee Young <workingjubilee@gmail.com>
Date: Thu, 17 Oct 2024 12:59:04 -0700
Subject: [PATCH] compiler: Adopt rust-analyzer impls for
 `LayoutCalculatorError`

---
 compiler/rustc_abi/src/layout.rs | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/compiler/rustc_abi/src/layout.rs b/compiler/rustc_abi/src/layout.rs
index 6e1299944a0..5ce5f14ce57 100644
--- a/compiler/rustc_abi/src/layout.rs
+++ b/compiler/rustc_abi/src/layout.rs
@@ -39,7 +39,7 @@ enum NicheBias {
     End,
 }
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 pub enum LayoutCalculatorError<F> {
     /// An unsized type was found in a location where a sized type was expected.
     ///
@@ -56,6 +56,31 @@ pub enum LayoutCalculatorError<F> {
     EmptyUnion,
 }
 
+impl<F> LayoutCalculatorError<F> {
+    pub fn without_payload(&self) -> LayoutCalculatorError<()> {
+        match self {
+            LayoutCalculatorError::UnexpectedUnsized(_) => {
+                LayoutCalculatorError::UnexpectedUnsized(())
+            }
+            LayoutCalculatorError::SizeOverflow => LayoutCalculatorError::SizeOverflow,
+            LayoutCalculatorError::EmptyUnion => LayoutCalculatorError::EmptyUnion,
+        }
+    }
+
+    /// Format an untranslated diagnostic for this type
+    ///
+    /// Intended for use by rust-analyzer, as neither it nor `rustc_abi` depend on fluent infra.
+    pub fn fallback_fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.write_str(match self {
+            LayoutCalculatorError::UnexpectedUnsized(_) => {
+                "an unsized type was found where a sized type was expected"
+            }
+            LayoutCalculatorError::SizeOverflow => "size overflow",
+            LayoutCalculatorError::EmptyUnion => "type is a union with no fields",
+        })
+    }
+}
+
 type LayoutCalculatorResult<FieldIdx, VariantIdx, F> =
     Result<LayoutS<FieldIdx, VariantIdx>, LayoutCalculatorError<F>>;