From 838f3b90e714b908cafdc43f3884fdc28747b2f7 Mon Sep 17 00:00:00 2001
From: Tom Hvitved <hvitved@github.com>
Date: Thu, 5 Mar 2026 20:49:58 +0100
Subject: [PATCH] Rust: Add type inference test

---
 .../type-inference/regressions.rs             | 42 ++++++++++++++++
 .../type-inference/type-inference.expected    | 48 +++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/rust/ql/test/library-tests/type-inference/regressions.rs b/rust/ql/test/library-tests/type-inference/regressions.rs
index 17475d50166..17a3d121c32 100644
--- a/rust/ql/test/library-tests/type-inference/regressions.rs
+++ b/rust/ql/test/library-tests/type-inference/regressions.rs
@@ -32,3 +32,45 @@ mod regression1 {
         opt_e.unwrap() // $ target=unwrap
     }
 }
+
+mod regression2 {
+    use std::ops::Sub;
+
+    #[derive(Copy, Clone)]
+    struct S1;
+    #[derive(Copy, Clone)]
+    struct S2;
+
+    impl Sub for S1 {
+        type Output = Self;
+
+        // S1SubS1
+        fn sub(self, _rhs: Self) -> Self::Output {
+            S1
+        }
+    }
+
+    impl Sub<S2> for S1 {
+        type Output = S2;
+
+        // S1SubS2
+        fn sub(self, _rhs: S2) -> Self::Output {
+            S2
+        }
+    }
+
+    impl Sub<&S2> for S1 {
+        type Output = <S1 as Sub<S2>>::Output;
+
+        // S1SubRefS2
+        fn sub(self, other: &S2) -> <S1 as Sub<S2>>::Output {
+            Sub::sub(self, *other) // $ target=S1SubS2 target=deref
+        }
+    }
+
+    fn foo() {
+        let s1 = S1;
+        let s2 = S2;
+        let x = s1 - &s2; // $ target=S1SubRefS2 type=x:S2 $ SPURIOUS: type=x:S1
+    }
+}
diff --git a/rust/ql/test/library-tests/type-inference/type-inference.expected b/rust/ql/test/library-tests/type-inference/type-inference.expected
index 5d0b167074a..fb302784b64 100644
--- a/rust/ql/test/library-tests/type-inference/type-inference.expected
+++ b/rust/ql/test/library-tests/type-inference/type-inference.expected
@@ -4947,6 +4947,22 @@ inferCertainType
 | regressions.rs:27:37:27:41 | vec_e |  | {EXTERNAL LOCATION} | Vec |
 | regressions.rs:27:37:27:41 | vec_e | A | {EXTERNAL LOCATION} | Global |
 | regressions.rs:28:9:30:9 | { ... } |  | {EXTERNAL LOCATION} | () |
+| regressions.rs:48:16:48:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:48:22:48:25 | _rhs |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:48:50:50:9 | { ... } |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:57:16:57:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:57:22:57:25 | _rhs |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:57:48:59:9 | { ... } |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:66:16:66:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:66:22:66:26 | other |  | {EXTERNAL LOCATION} | & |
+| regressions.rs:66:22:66:26 | other | TRef | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:66:61:68:9 | { ... } |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:66:61:68:9 | { ... } |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:67:22:67:25 | self |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:67:29:67:33 | other |  | {EXTERNAL LOCATION} | & |
+| regressions.rs:67:29:67:33 | other | TRef | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:71:14:75:5 | { ... } |  | {EXTERNAL LOCATION} | () |
+| regressions.rs:74:22:74:24 | &s2 |  | {EXTERNAL LOCATION} | & |
 inferType
 | associated_types.rs:5:15:5:18 | SelfParam |  | associated_types.rs:1:1:2:21 | Wrapper |
 | associated_types.rs:5:15:5:18 | SelfParam | A | associated_types.rs:4:6:4:6 | A |
@@ -14789,4 +14805,36 @@ inferType
 | regressions.rs:32:9:32:13 | opt_e |  | {EXTERNAL LOCATION} | Option |
 | regressions.rs:32:9:32:13 | opt_e | T | regressions.rs:5:5:7:5 | E |
 | regressions.rs:32:9:32:22 | opt_e.unwrap() |  | regressions.rs:5:5:7:5 | E |
+| regressions.rs:48:16:48:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:48:22:48:25 | _rhs |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:48:50:50:9 | { ... } |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:49:13:49:14 | S1 |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:57:16:57:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:57:22:57:25 | _rhs |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:57:48:59:9 | { ... } |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:58:13:58:14 | S2 |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:66:16:66:19 | SelfParam |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:66:22:66:26 | other |  | {EXTERNAL LOCATION} | & |
+| regressions.rs:66:22:66:26 | other | TRef | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:66:61:68:9 | { ... } |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:66:61:68:9 | { ... } |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:67:13:67:34 | ...::sub(...) |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:67:13:67:34 | ...::sub(...) |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:67:22:67:25 | self |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:67:28:67:33 | * ... |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:67:29:67:33 | other |  | {EXTERNAL LOCATION} | & |
+| regressions.rs:67:29:67:33 | other | TRef | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:71:14:75:5 | { ... } |  | {EXTERNAL LOCATION} | () |
+| regressions.rs:72:13:72:14 | s1 |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:72:18:72:19 | S1 |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:73:13:73:14 | s2 |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:73:18:73:19 | S2 |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:74:13:74:13 | x |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:74:13:74:13 | x |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:74:17:74:18 | s1 |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:74:17:74:24 | ... - ... |  | regressions.rs:39:5:40:14 | S1 |
+| regressions.rs:74:17:74:24 | ... - ... |  | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:74:22:74:24 | &s2 |  | {EXTERNAL LOCATION} | & |
+| regressions.rs:74:22:74:24 | &s2 | TRef | regressions.rs:41:5:42:14 | S2 |
+| regressions.rs:74:23:74:24 | s2 |  | regressions.rs:41:5:42:14 | S2 |
 testFailures