Rollup merge of rust-lang#65191 - varkor:const-generics-test-cases, r…

…=nikomatsakis

Add some regression tests

- Add a test for rust-lang#62187.
- Clean up the directory structure in `src/test/ui/const-generics`
- Closes rust-lang#64792.
- Closes rust-lang#57399.
- Closes rust-lang#57271.

src/test/ui/const-generics/issues/issue-62187-encountered-polymorphic-const.rs

@@ -0,0 +1,16 @@
+// run-pass
+
+#![feature(const_generics)]
+//~^ WARN the feature `const_generics` is incomplete and may cause the compiler to crash
+
+pub trait BitLen: Sized {
+    const BIT_LEN: usize;
+}
+
+impl<const L: usize> BitLen for [u8; L] {
+    const BIT_LEN: usize = 8 * L;
+}
+
+fn main() {
+    let foo = <[u8; 2]>::BIT_LEN;
+}

src/test/ui/const-generics/issues/issue-62187-encountered-polymorphic-const.stderr

@@ -0,0 +1,16 @@
+warning: the feature `const_generics` is incomplete and may cause the compiler to crash
+  --> $DIR/issue-62187-encountered-polymorphic-const.rs:3:12
+   |
+LL | #![feature(const_generics)]
+   |            ^^^^^^^^^^^^^^
+   |
+   = note: `#[warn(incomplete_features)]` on by default
+
+warning: unused variable: `foo`
+  --> $DIR/issue-62187-encountered-polymorphic-const.rs:15:9
+   |
+LL |     let foo = <[u8; 2]>::BIT_LEN;
+   |         ^^^ help: consider prefixing with an underscore: `_foo`
+   |
+   = note: `#[warn(unused_variables)]` on by default
+

src/test/ui/issues/auxiliary/issue-57271-lib.rs

@@ -0,0 +1,11 @@
+#[derive(Copy, Clone, Debug, Eq, PartialEq, Hash)]
+pub enum BaseType {
+    Byte,
+    Char,
+    Double,
+    Float,
+    Int,
+    Long,
+    Short,
+    Boolean,
+}

src/test/ui/issues/issue-57271.rs

@@ -0,0 +1,24 @@
+// aux-build:issue-57271-lib.rs
+
+extern crate issue_57271_lib;
+
+use issue_57271_lib::BaseType;
+
+pub enum ObjectType { //~ ERROR recursive type `ObjectType` has infinite size
+    Class(ClassTypeSignature),
+    Array(TypeSignature),
+    TypeVariable(()),
+}
+
+pub struct ClassTypeSignature {
+    pub package: (),
+    pub class: (),
+    pub inner: (),
+}
+
+pub enum TypeSignature { //~ ERROR recursive type `TypeSignature` has infinite size
+    Base(BaseType),
+    Object(ObjectType),
+}
+
+fn main() {}

src/test/ui/issues/issue-57271.stderr

@@ -0,0 +1,25 @@
+error[E0072]: recursive type `ObjectType` has infinite size
+  --> $DIR/issue-57271.rs:7:1
+   |
+LL | pub enum ObjectType {
+   | ^^^^^^^^^^^^^^^^^^^ recursive type has infinite size
+LL |     Class(ClassTypeSignature),
+LL |     Array(TypeSignature),
+   |           ------------- recursive without indirection
+   |
+   = help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `ObjectType` representable
+
+error[E0072]: recursive type `TypeSignature` has infinite size
+  --> $DIR/issue-57271.rs:19:1
+   |
+LL | pub enum TypeSignature {
+   | ^^^^^^^^^^^^^^^^^^^^^^ recursive type has infinite size
+LL |     Base(BaseType),
+LL |     Object(ObjectType),
+   |            ---------- recursive without indirection
+   |
+   = help: insert indirection (e.g., a `Box`, `Rc`, or `&`) at some point to make `TypeSignature` representable
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0072`.

src/test/ui/issues/issue-57399-self-return-impl-trait.rs

@@ -0,0 +1,22 @@
+// run-pass
+
+trait T {
+    type T;
+}
+
+impl T for i32 {
+    type T = u32;
+}
+
+struct S<A> {
+    a: A,
+}
+
+
+impl From<u32> for S<<i32 as T>::T> {
+    fn from(a: u32) -> Self {
+        Self { a }
+    }
+}
+
+fn main() {}

src/test/ui/issues/issue-57399-self-return-impl-trait.stderr

@@ -0,0 +1,8 @@
+warning: field is never used: `a`
+  --> $DIR/issue-57399-self-return-impl-trait.rs:12:5
+   |
+LL |     a: A,
+   |     ^^^^
+   |
+   = note: `#[warn(dead_code)]` on by default
+

src/test/ui/issues/issue-64792-bad-unicode-ctor.rs

@@ -0,0 +1,5 @@
+struct X {}
+
+const Y: X = X("ö"); //~ ERROR expected function, found struct `X`
+
+fn main() {}

src/test/ui/issues/issue-64792-bad-unicode-ctor.stderr

@@ -0,0 +1,15 @@
+error[E0423]: expected function, found struct `X`
+  --> $DIR/issue-64792-bad-unicode-ctor.rs:3:14
+   |
+LL | struct X {}
+   | ----------- `X` defined here
+LL | 
+LL | const Y: X = X("ö");
+   |              ^
+   |              |
+   |              did you mean `X { /* fields */ }`?
+   |              help: a constant with a similar name exists: `Y`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0423`.