Rollup merge of #150886 - mgca-test, r=BoxyUwU

Added mGCA related tests

Add regression tests for subsequent mGCA tasks

edit:

resolve: https://github.com/rust-lang/rust/issues/147415 `tests\ui\const-generics\mgca\size-of-generic-ptr-in-array-len.rs`
resolve: https://github.com/rust-lang/rust/issues/141014 `tests\ui\const-generics\mgca\assoc-const-projection-in-bound.rs`

and crashes: 138226, 138226-2, 149809, 150960

tests/crashes/138226-2.rs

@@ -0,0 +1,13 @@
+//@ known-bug: #138226
+//@ needs-rustc-debug-assertions
+#![feature(min_generic_const_args)]
+#![feature(inherent_associated_types)]
+struct Bar<const N: usize>;
+impl<const N: usize> Bar<N> {
+    #[type_const]
+    const LEN: usize = 4;
+
+    fn bar() {
+        let _ = [0; Self::LEN];
+    }
+}

tests/crashes/138226.rs

@@ -0,0 +1,13 @@
+//@ known-bug: #138226
+//@ needs-rustc-debug-assertions
+#![feature(min_generic_const_args)]
+#![feature(inherent_associated_types)]
+struct Foo<A, B>(A, B);
+impl<A, B> Foo<A, B> {
+    #[type_const]
+    const LEN: usize = 4;
+
+    fn foo() {
+        let _ = [5; Self::LEN];
+    }
+}

tests/crashes/149809.rs

@@ -0,0 +1,13 @@
+//@ known-bug: #149809
+#![feature(min_generic_const_args)]
+#![feature(inherent_associated_types)]
+struct Qux<'a> {
+    x: &'a (),
+}
+impl<'a> Qux<'a> {
+    #[type_const]
+    const LEN: usize = 4;
+    fn foo(_: [u8; Qux::LEN]) {}
+}
+
+fn main() {}

tests/crashes/150960.rs

@@ -0,0 +1,11 @@
+//@ known-bug: #150960
+#![feature(min_generic_const_args)]
+struct Baz;
+impl Baz {
+    #[type_const]
+    const LEN: usize = 4;
+
+    fn baz() {
+        let _ = [0; const { Self::LEN }];
+    }
+}

tests/ui/const-generics/mgca/assoc-const-projection-in-bound.rs

@@ -0,0 +1,27 @@
+//! regression test for <https://github.com/rust-lang/rust/issues/141014>
+//@ run-pass
+#![expect(incomplete_features)]
+#![feature(min_generic_const_args)]
+#![allow(dead_code)]
+
+trait Abc {}
+
+trait A {
+    #[type_const]
+    const VALUE: usize;
+}
+
+impl<T: Abc> A for T {
+    #[type_const]
+    const VALUE: usize = 0;
+}
+
+trait S<const K: usize> {}
+
+trait Handler<T: Abc>
+where
+    (): S<{ <T as A>::VALUE }>,
+{
+}
+
+fn main() {}

tests/ui/const-generics/mgca/size-of-generic-ptr-in-array-len.rs

@@ -0,0 +1,12 @@
+//! regression test for <https://github.com/rust-lang/rust/issues/147415>
+#![expect(incomplete_features)]
+#![feature(min_generic_const_args)]
+
+fn foo<T>() {
+    [0; size_of::<*mut T>()];
+    //~^ ERROR: tuple constructor with invalid base path
+    [0; const { size_of::<*mut T>() }];
+    //~^ ERROR: generic parameters may not be used in const operations
+}
+
+fn main() {}

tests/ui/const-generics/mgca/size-of-generic-ptr-in-array-len.stderr

@@ -0,0 +1,14 @@
+error: tuple constructor with invalid base path
+  --> $DIR/size-of-generic-ptr-in-array-len.rs:6:9
+   |
+LL |     [0; size_of::<*mut T>()];
+   |         ^^^^^^^^^^^^^^^^^^^
+
+error: generic parameters may not be used in const operations
+  --> $DIR/size-of-generic-ptr-in-array-len.rs:8:32
+   |
+LL |     [0; const { size_of::<*mut T>() }];
+   |                                ^
+
+error: aborting due to 2 previous errors
+