Auto merge of #18119 - ChayimFriedman2:signed-const, r=HKalbasi

fix: Fix printing of constants greater than `i128::MAX`

Fixes #18116.

2 files changed, 27 insertions, 3 deletions

diff --git a/src/tools/rust-analyzer/crates/hir/src/lib.rs b/src/tools/rust-analyzer/crates/hir/src/lib.rs
index e3bd7562083..176c059bf62 100644
--- a/src/tools/rust-analyzer/crates/hir/src/lib.rs
+++ b/src/tools/rust-analyzer/crates/hir/src/lib.rs
@@ -80,7 +80,7 @@ use nameres::diagnostics::DefDiagnosticKind;
 use rustc_hash::FxHashSet;
 use smallvec::SmallVec;
 use span::{Edition, EditionedFileId, FileId, MacroCallId, SyntaxContextId};
-use stdx::{impl_from, never};
+use stdx::{format_to, impl_from, never};
 use syntax::{
     ast::{self, HasAttrs as _, HasGenericParams, HasName},
     format_smolstr, AstNode, AstPtr, SmolStr, SyntaxNode, SyntaxNodePtr, TextRange, ToSmolStr, T,
@@ -2578,10 +2578,16 @@ impl Const {
                         let value = u128::from_le_bytes(mir::pad16(b, false));
                         let value_signed =
                             i128::from_le_bytes(mir::pad16(b, matches!(s, Scalar::Int(_))));
+                        let mut result = if let Scalar::Int(_) = s {
+                            value_signed.to_string()
+                        } else {
+                            value.to_string()
+                        };
                         if value >= 10 {
-                            return Ok(format!("{value_signed} ({value:#X})"));
+                            format_to!(result, " ({value:#X})");
+                            return Ok(result);
                         } else {
-                            return Ok(format!("{value_signed}"));
+                            return Ok(result);
                         }
                     }
                 }
diff --git a/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs b/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
index f2e5d24fcc6..8805ead818a 100644
--- a/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
+++ b/src/tools/rust-analyzer/crates/ide/src/hover/tests.rs
@@ -1497,6 +1497,24 @@ const foo$0: u32 = {
 }
 
 #[test]
+fn hover_unsigned_max_const() {
+    check(
+        r#"const $0A: u128 = -1_i128 as u128;"#,
+        expect![[r#"
+            *A*
+
+            ```rust
+            test
+            ```
+
+            ```rust
+            const A: u128 = 340282366920938463463374607431768211455 (0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF)
+            ```
+        "#]],
+    );
+}
+
+#[test]
 fn hover_eval_complex_constants() {
     check(
         r#"