From 887ed5b9e999db0f6c5d0419b47fc4801803484f Mon Sep 17 00:00:00 2001
From: Christoffer Lerno <christoffer@aegik.com>
Date: Mon, 24 Nov 2025 12:46:31 +0100
Subject: [PATCH] - `String.to_integer` does not correctly return in some cases
 where it should #2590.

---
 lib/std/core/string.c3                 |  8 ++---
 releasenotes.md                        |  1 +
 test/unit/stdlib/core/string_to_int.c3 | 42 ++++++++++++++++++++++++++
 3 files changed, 45 insertions(+), 6 deletions(-)
 create mode 100644 test/unit/stdlib/core/string_to_int.c3

diff --git a/lib/std/core/string.c3 b/lib/std/core/string.c3
index 7ffb8e7e7..d0be62551 100644
--- a/lib/std/core/string.c3
+++ b/lib/std/core/string.c3
@@ -1067,14 +1067,10 @@ macro String.to_integer(self, $Type, int base = 10)
 		{
 			if (is_negative)
 			{
-				$Type new_value = value * base_used - c;
-				if (new_value > value) return INTEGER_OVERFLOW?;
-				value = new_value;
+				value = value.overflow_mul(base_used).overflow_sub(c) ?? INTEGER_OVERFLOW?!;
 				break;
 			}
-			$Type new_value = value * base_used + c;
-			if (new_value < value) return INTEGER_OVERFLOW?;
-			value = new_value;
+			value = value.overflow_mul(base_used).overflow_add(c) ?? INTEGER_OVERFLOW?!;
 		};
 	}
 	return value;
diff --git a/releasenotes.md b/releasenotes.md
index b51566536..60ba46ad9 100644
--- a/releasenotes.md
+++ b/releasenotes.md
@@ -39,6 +39,7 @@
 - With project.json, when overriding with an empty list the base settings would still be used. #2583
 - Add sigsegv stacktrace in test and regular errors for Darwin Arm64. #1105
 - Incorrect error message when using generic type that isn't imported #2589
+- `String.to_integer` does not correctly return in some cases where it should #2590.
 
 ### Stdlib changes
 - Add `CGFloat` `CGPoint` `CGSize` `CGRect` types to core_foundation (macOS).
diff --git a/test/unit/stdlib/core/string_to_int.c3 b/test/unit/stdlib/core/string_to_int.c3
new file mode 100644
index 000000000..7248accdc
--- /dev/null
+++ b/test/unit/stdlib/core/string_to_int.c3
@@ -0,0 +1,42 @@
+module string_to_int;
+import std::io, std::math;
+
+const N = 2560;
+macro String[] m() @const
+{
+    var $strings = {};
+    $foreach $i : math::iota(int[N]):
+        $strings +++= @sprintf("%s", $i);
+    $endforeach
+    return $strings;
+}
+
+macro String[] m2() @const
+{
+    var $strings = {};
+    $foreach $i : math::iota(int[N]):
+        $strings +++= @sprintf("%s", -$i);
+    $endforeach
+    return $strings;
+}
+
+fn void string_to_char() @test
+{
+	int valid = 0;
+    foreach (str : m())
+    {
+        char? x = str.to_integer(char);
+        if (try x) valid++;
+    }
+    assert(valid == 256);
+}
+fn void string_to_ichar() @test
+{
+	int valid = 0;
+    foreach (str : m2())
+    {
+        ichar? x = str.to_integer(ichar);
+        if (try x) valid++;
+    }
+    assert(valid == 129);
+}
\ No newline at end of file