moved renamed docs stderr formatted | destructure-trait-ref.rs

Author: Kivooeo

tests/ui/destructure-trait-ref.rs

@@ -0,0 +1,29 @@
+//! Regression test for destructuring trait references (`&dyn T`/`Box<dyn T>`).
+//! Checks cases where number of `&`/`Box` patterns (n) matches/doesn't match references (m).
+//!
+//! Issue: https://github.com/rust-lang/rust/issues/15031
+
+#![feature(box_patterns)]
+
+trait T {
+    fn foo(&self) {}
+}
+
+impl T for isize {}
+
+fn main() {
+    // Valid cases: n < m (can dereference)
+    let &x = &(&1isize as &dyn T);
+    let &x = &&(&1isize as &dyn T);
+    let &&x = &&(&1isize as &dyn T);
+
+    // Error cases: n == m (cannot dereference trait object)
+    let &x = &1isize as &dyn T; //~ ERROR type `&dyn T` cannot be dereferenced
+    let &&x = &(&1isize as &dyn T); //~ ERROR type `&dyn T` cannot be dereferenced
+    let box x = Box::new(1isize) as Box<dyn T>; //~ ERROR type `Box<dyn T>` cannot be dereferenced
+
+    // Error cases: n > m (type mismatch)
+    let &&x = &1isize as &dyn T; //~ ERROR mismatched types
+    let &&&x = &(&1isize as &dyn T); //~ ERROR mismatched types
+    let box box x = Box::new(1isize) as Box<dyn T>; //~ ERROR mismatched types
+}

tests/ui/traits/trait-object-destructure.rs

@@ -1,23 +1,23 @@
 error[E0033]: type `&dyn T` cannot be dereferenced
-  --> $DIR/destructure-trait-ref.rs:28:9
+  --> $DIR/trait-object-destructure.rs:21:9
    |
 LL |     let &x = &1isize as &dyn T;
    |         ^^ type `&dyn T` cannot be dereferenced
 
 error[E0033]: type `&dyn T` cannot be dereferenced
-  --> $DIR/destructure-trait-ref.rs:29:10
+  --> $DIR/trait-object-destructure.rs:22:10
    |
 LL |     let &&x = &(&1isize as &dyn T);
    |          ^^ type `&dyn T` cannot be dereferenced
 
 error[E0033]: type `Box<dyn T>` cannot be dereferenced
-  --> $DIR/destructure-trait-ref.rs:30:9
+  --> $DIR/trait-object-destructure.rs:23:9
    |
 LL |     let box x = Box::new(1isize) as Box<dyn T>;
    |         ^^^^^ type `Box<dyn T>` cannot be dereferenced
 
 error[E0308]: mismatched types
-  --> $DIR/destructure-trait-ref.rs:34:10
+  --> $DIR/trait-object-destructure.rs:26:10
    |
 LL |     let &&x = &1isize as &dyn T;
    |          ^^   ----------------- this expression has type `&dyn T`
@@ -33,7 +33,7 @@ LL +     let &x = &1isize as &dyn T;
    |
 
 error[E0308]: mismatched types
-  --> $DIR/destructure-trait-ref.rs:38:11
+  --> $DIR/trait-object-destructure.rs:27:11
    |
 LL |     let &&&x = &(&1isize as &dyn T);
    |           ^^   -------------------- this expression has type `&&dyn T`
@@ -49,7 +49,7 @@ LL +     let &&x = &(&1isize as &dyn T);
    |
 
 error[E0308]: mismatched types
-  --> $DIR/destructure-trait-ref.rs:42:13
+  --> $DIR/trait-object-destructure.rs:28:13
    |
 LL |     let box box x = Box::new(1isize) as Box<dyn T>;
    |             ^^^^^   ------------------------------ this expression has type `Box<dyn T>`