From 91eb4dad4e539551c8ab050de32f61acb7fc4409 Mon Sep 17 00:00:00 2001
From: Geoffrey White <40627776+geoffw0@users.noreply.github.com>
Date: Wed, 13 Aug 2025 12:22:52 +0100
Subject: [PATCH] Rust: Add a type inference test case resembling
 PathBuf.canonicalize.

---
 .../test/library-tests/type-inference/main.rs | 51 ++++++++++++++++++-
 .../type-inference/type-inference.expected    | 48 +++++++++++++++--
 2 files changed, 93 insertions(+), 6 deletions(-)

diff --git a/rust/ql/test/library-tests/type-inference/main.rs b/rust/ql/test/library-tests/type-inference/main.rs
index 1006fd207c8a..d18d37b92c8f 100644
--- a/rust/ql/test/library-tests/type-inference/main.rs
+++ b/rust/ql/test/library-tests/type-inference/main.rs
@@ -2515,7 +2515,7 @@ pub mod pattern_matching_experimental {
 }
 
 pub mod exec {
-    // a *greatly* simplified model of `MySqlConnection.execute` in SQLX
+    // a highly simplified model of `MySqlConnection.execute` in SQLx
 
     trait Connection {}
 
@@ -2551,6 +2551,54 @@ pub mod exec {
     }
 }
 
+pub mod path_buf {
+    // a highly simplified model of `PathBuf::canonicalize`
+
+    pub struct Path {
+    }
+
+    impl Path {
+        pub const fn new() -> Path {
+            Path { }
+        }
+
+        pub fn canonicalize(&self) -> Result<PathBuf, ()> {
+            Ok(PathBuf::new()) // $ target=new
+        }
+    }
+
+    pub struct PathBuf {
+    }
+
+    impl PathBuf {
+        pub const fn new() -> PathBuf {
+            PathBuf { }
+        }
+    }
+
+    // `PathBuf` provides `canonicalize` via `Deref`:
+    impl std::ops::Deref for PathBuf {
+        type Target = Path;
+
+        #[inline]
+        fn deref(&self) -> &Path {
+            // (very much not a real implementation)
+            static path : Path = Path::new(); // $ target=new
+            &path
+        }
+    }
+
+    pub fn f() {
+        let path1 = Path::new(); // $ target=new type=path1:Path
+        let path2 = path1.canonicalize(); // $ target=canonicalize
+        let path3 = path2.unwrap(); // $ target=unwrap type=path3:PathBuf
+
+        let pathbuf1 = PathBuf::new(); // $ target=new type=pathbuf1:PathBuf
+        let pathbuf2 = pathbuf1.canonicalize(); // $ MISSING: target=canonicalize
+        let pathbuf3 = pathbuf2.unwrap(); // $ MISSING: target=unwrap type=pathbuf3:PathBuf
+    }
+}
+
 mod closure;
 mod dereference;
 mod dyn_type;
@@ -2583,6 +2631,7 @@ fn main() {
     method_determined_by_argument_type::f(); // $ target=f
     tuples::f(); // $ target=f
     exec::f(); // $ target=f
+    path_buf::f(); // $ target=f
     dereference::test(); // $ target=test
     pattern_matching::test_all_patterns(); // $ target=test_all_patterns
     pattern_matching_experimental::box_patterns(); // $ target=box_patterns
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 5b8bf2e4f301..a33342d3ee81 100644
--- a/rust/ql/test/library-tests/type-inference/type-inference.expected
+++ b/rust/ql/test/library-tests/type-inference/type-inference.expected
@@ -4934,11 +4934,49 @@ inferType
 | main.rs:2550:44:2550:44 | c |  | main.rs:2537:5:2537:29 | MySqlConnection |
 | main.rs:2550:47:2550:67 | "SELECT * FROM users" |  | file://:0:0:0:0 | & |
 | main.rs:2550:47:2550:67 | "SELECT * FROM users" | &T | {EXTERNAL LOCATION} | str |
-| main.rs:2560:5:2560:20 | ...::f(...) |  | main.rs:72:5:72:21 | Foo |
-| main.rs:2561:5:2561:60 | ...::g(...) |  | main.rs:72:5:72:21 | Foo |
-| main.rs:2561:20:2561:38 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
-| main.rs:2561:41:2561:59 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
-| main.rs:2577:5:2577:15 | ...::f(...) |  | {EXTERNAL LOCATION} | trait Future |
+| main.rs:2561:36:2563:9 | { ... } |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2562:13:2562:20 | Path {...} |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2565:29:2565:33 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:2565:29:2565:33 | SelfParam | &T | main.rs:2557:5:2558:5 | Path |
+| main.rs:2565:59:2567:9 | { ... } |  | {EXTERNAL LOCATION} | Result |
+| main.rs:2565:59:2567:9 | { ... } | E | file://:0:0:0:0 | () |
+| main.rs:2565:59:2567:9 | { ... } | T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2566:13:2566:30 | Ok(...) |  | {EXTERNAL LOCATION} | Result |
+| main.rs:2566:13:2566:30 | Ok(...) | E | file://:0:0:0:0 | () |
+| main.rs:2566:13:2566:30 | Ok(...) | T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2566:16:2566:29 | ...::new(...) |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2574:39:2576:9 | { ... } |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2575:13:2575:23 | PathBuf {...} |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2584:18:2584:22 | SelfParam |  | file://:0:0:0:0 | & |
+| main.rs:2584:18:2584:22 | SelfParam | &T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2584:34:2588:9 | { ... } |  | file://:0:0:0:0 | & |
+| main.rs:2584:34:2588:9 | { ... } | &T | main.rs:2557:5:2558:5 | Path |
+| main.rs:2586:34:2586:44 | ...::new(...) |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2587:13:2587:17 | &path |  | file://:0:0:0:0 | & |
+| main.rs:2587:13:2587:17 | &path | &T | main.rs:2557:5:2558:5 | Path |
+| main.rs:2587:14:2587:17 | path |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2592:13:2592:17 | path1 |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2592:21:2592:31 | ...::new(...) |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2593:13:2593:17 | path2 |  | {EXTERNAL LOCATION} | Result |
+| main.rs:2593:13:2593:17 | path2 | E | file://:0:0:0:0 | () |
+| main.rs:2593:13:2593:17 | path2 | T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2593:21:2593:25 | path1 |  | main.rs:2557:5:2558:5 | Path |
+| main.rs:2593:21:2593:40 | path1.canonicalize() |  | {EXTERNAL LOCATION} | Result |
+| main.rs:2593:21:2593:40 | path1.canonicalize() | E | file://:0:0:0:0 | () |
+| main.rs:2593:21:2593:40 | path1.canonicalize() | T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2594:13:2594:17 | path3 |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2594:21:2594:25 | path2 |  | {EXTERNAL LOCATION} | Result |
+| main.rs:2594:21:2594:25 | path2 | E | file://:0:0:0:0 | () |
+| main.rs:2594:21:2594:25 | path2 | T | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2594:21:2594:34 | path2.unwrap() |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2596:13:2596:20 | pathbuf1 |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2596:24:2596:37 | ...::new(...) |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2597:24:2597:31 | pathbuf1 |  | main.rs:2570:5:2571:5 | PathBuf |
+| main.rs:2608:5:2608:20 | ...::f(...) |  | main.rs:72:5:72:21 | Foo |
+| main.rs:2609:5:2609:60 | ...::g(...) |  | main.rs:72:5:72:21 | Foo |
+| main.rs:2609:20:2609:38 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
+| main.rs:2609:41:2609:59 | ...::Foo {...} |  | main.rs:72:5:72:21 | Foo |
+| main.rs:2625:5:2625:15 | ...::f(...) |  | {EXTERNAL LOCATION} | trait Future |
 | pattern_matching.rs:13:26:133:1 | { ... } |  | {EXTERNAL LOCATION} | Option |
 | pattern_matching.rs:13:26:133:1 | { ... } | T | file://:0:0:0:0 | () |
 | pattern_matching.rs:14:9:14:13 | value |  | {EXTERNAL LOCATION} | Option |