Rust: Add more type inference tests

Author: hvitved

rust/ql/test/library-tests/type-inference/overloading.rs

@@ -400,3 +400,52 @@ mod from_default {
         x
     }
 }
+
+mod inherent_before_trait {
+    struct S<T>(T);
+
+    trait Trait {
+        fn foo(&self);
+        fn bar(&self);
+    }
+
+    impl S<i32> {
+        // S<i32>::foo
+        fn foo(x: &Self) {}
+
+        // S<i32>::bar
+        fn bar(&self) {}
+    }
+
+    impl Trait for S<i32> {
+        // <S<i32>_as_Trait>::foo
+        fn foo(&self) {
+            S::foo(self); // $ MISSING: target=S<i32>::foo
+            S::<i32>::foo(self); // $ MISSING: target=S<i32>::foo
+            self.foo() // $ target=<S<i32>_as_Trait>::foo
+        }
+
+        // <S<i32>_as_Trait>::bar
+        fn bar(&self) {
+            S::bar(self); // $ target=S<i32>::bar
+            S::<i32>::bar(self); // $ target=S<i32>::bar
+            self.bar() // $ target=S<i32>::bar
+        }
+    }
+
+    impl Trait for S<i64> {
+        // <S<i64>_as_Trait>::foo
+        fn foo(&self) {
+            // `S::foo(self);` is not valid
+            S::<i64>::foo(self); // $ MISSING: target=<S<i64>_as_Trait>::foo
+            self.foo() // $ target=<S<i64>_as_Trait>::foo
+        }
+
+        // <S<i64>_as_Trait>::bar
+        fn bar(&self) {
+            // `S::bar(self);` is not valid
+            S::<i64>::bar(self); // $ target=<S<i64>_as_Trait>::bar
+            self.bar() // $ target=<S<i64>_as_Trait>::bar
+        }
+    }
+}

rust/ql/test/library-tests/type-inference/regressions.rs

@@ -74,3 +74,35 @@ mod regression2 {
         let x = s1 - &s2; // $ target=S1SubRefS2 type=x:S2
     }
 }
+
+mod regression3 {
+    trait SomeTrait {}
+
+    trait MyFrom<T> {
+        fn my_from(value: T) -> Self;
+    }
+
+    impl<T> MyFrom<T> for T {
+        fn my_from(s: T) -> Self {
+            s
+        }
+    }
+
+    impl<T> MyFrom<T> for Option<T> {
+        fn my_from(val: T) -> Option<T> {
+            Some(val)
+        }
+    }
+
+    pub struct S<Ts>(Ts);
+
+    pub fn f<T1, T2>(x: T2) -> T2
+    where
+        T2: SomeTrait + MyFrom<Option<T1>>,
+        Option<T1>: MyFrom<T2>,
+    {
+        let y = MyFrom::my_from(x); // $ target=my_from
+        let z = MyFrom::my_from(y); // $ target=my_from
+        z
+    }
+}