Auto merge of #133818 - matthiaskrgr:rollup-iav1wq7, r=matthiaskrgr

Rollup of 7 pull requests

Successful merges:

 - #132937 (a release operation synchronizes with an acquire operation)
 - #133681 (improve TagEncoding::Niche docs, sanity check, and UB checks)
 - #133726 (Add `core::arch::breakpoint` and test)
 - #133768 (Remove `generic_associated_types_extended` feature gate)
 - #133811 ([AIX] change AIX default codemodel=large)
 - #133812 (Update wasm-component-ld to 0.5.11)
 - #133813 (compiletest: explain that UI tests are expected not to compile by default)

r? `@ghost`
`@rustbot` modify labels: rollup

tests/fail/breakpoint.rs

@@ -1,7 +1,5 @@
 #![feature(core_intrinsics)]
 
 fn main() {
-    unsafe {
-        core::intrinsics::breakpoint() //~ ERROR: trace/breakpoint trap
-    };
+    core::intrinsics::breakpoint(); //~ ERROR: trace/breakpoint trap
 }

tests/fail/breakpoint.stderr

@@ -1,8 +1,8 @@
 error: abnormal termination: trace/breakpoint trap
   --> tests/fail/breakpoint.rs:LL:CC
    |
-LL |         core::intrinsics::breakpoint()
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trace/breakpoint trap
+LL |     core::intrinsics::breakpoint();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ trace/breakpoint trap
    |
    = note: BACKTRACE:
    = note: inside `main` at tests/fail/breakpoint.rs:LL:CC

tests/fail/enum-untagged-variant-invalid-encoding.rs

@@ -0,0 +1,27 @@
+// Validity makes this fail at the wrong place.
+//@compile-flags: -Zmiri-disable-validation
+use std::mem;
+
+// This enum has untagged variant idx 1, with niche_variants being 0..=2
+// and niche_start being 2.
+// That means the untagged variants is in the niche variant range!
+// However, using the corresponding value (2+1 = 3) is not a valid encoding of this variant.
+#[derive(Copy, Clone, PartialEq)]
+enum Foo {
+    Var1,
+    Var2(bool),
+    Var3,
+}
+
+fn main() {
+    unsafe {
+        assert!(Foo::Var2(false) == mem::transmute(0u8));
+        assert!(Foo::Var2(true) == mem::transmute(1u8));
+        assert!(Foo::Var1 == mem::transmute(2u8));
+        assert!(Foo::Var3 == mem::transmute(4u8));
+
+        let invalid: Foo = mem::transmute(3u8);
+        assert!(matches!(invalid, Foo::Var2(_)));
+        //~^ ERROR: invalid tag
+    }
+}

tests/fail/enum-untagged-variant-invalid-encoding.stderr

@@ -0,0 +1,15 @@
+error: Undefined Behavior: enum value has invalid tag: 0x03
+  --> tests/fail/enum-untagged-variant-invalid-encoding.rs:LL:CC
+   |
+LL |         assert!(matches!(invalid, Foo::Var2(_)));
+   |                          ^^^^^^^ enum value has invalid tag: 0x03
+   |
+   = help: this indicates a bug in the program: it performed an invalid operation, and caused Undefined Behavior
+   = help: see https://doc.rust-lang.org/nightly/reference/behavior-considered-undefined.html for further information
+   = note: BACKTRACE:
+   = note: inside `main` at tests/fail/enum-untagged-variant-invalid-encoding.rs:LL:CC
+
+note: some details are omitted, run with `MIRIFLAGS=-Zmiri-backtrace=full` for a verbose backtrace
+
+error: aborting due to 1 previous error
+