Auto merge of #88400 - Mark-Simulacrum:beta-next, r=Mark-Simulacrum

[beta] backports

This PR rolls up a number of beta backports:

* Split critical edge targeting the start block #88124
* Make BuildHasher object safe #88031
* Fix Windows Command::env("PATH") #87863
* Do not ICE on HIR based WF check when involving lifetimes #87811
* Update compiler_builtins to fix i128 shift/mul on thumbv6m #87633

3 files changed, 80 insertions, 0 deletions

diff --git a/src/test/ui/codegen/issue-88043-bb-does-not-have-terminator.rs b/src/test/ui/codegen/issue-88043-bb-does-not-have-terminator.rs
new file mode 100644
index 00000000000..38dfca347c8
--- /dev/null
+++ b/src/test/ui/codegen/issue-88043-bb-does-not-have-terminator.rs
@@ -0,0 +1,35 @@
+// build-pass
+// compile-flags: -Copt-level=0
+
+// Regression test for #88043: LLVM crash when the RemoveZsts mir-opt pass is enabled.
+// We should not see the error:
+// `Basic Block in function '_ZN4main10take_until17h0067b8a660429bc9E' does not have terminator!`
+
+fn bump() -> Option<usize> {
+    unreachable!()
+}
+
+fn take_until(terminate: impl Fn() -> bool) {
+    loop {
+        if terminate() {
+            return;
+        } else {
+            bump();
+        }
+    }
+}
+
+// CHECK-LABEL: @main
+fn main() {
+    take_until(|| true);
+    f(None);
+}
+
+fn f(_a: Option<String>) -> Option<u32> {
+    loop {
+        g();
+        ()
+    }
+}
+
+fn g() -> Option<u32> { None }
diff --git a/src/test/ui/wf/hir-wf-check-erase-regions.rs b/src/test/ui/wf/hir-wf-check-erase-regions.rs
new file mode 100644
index 00000000000..bb398e5698a
--- /dev/null
+++ b/src/test/ui/wf/hir-wf-check-erase-regions.rs
@@ -0,0 +1,14 @@
+// Regression test for #87549.
+// compile-flags: -C incremental=tmp/wf/hir-wf-check-erase-regions
+
+pub struct Table<T, const N: usize>([Option<T>; N]);
+
+impl<'a, T, const N: usize> IntoIterator for &'a Table<T, N> {
+    type IntoIter = std::iter::Flatten<std::slice::Iter<'a, T>>; //~ ERROR `&T` is not an iterator
+    type Item = &'a T;
+
+    fn into_iter(self) -> Self::IntoIter { //~ ERROR `&T` is not an iterator
+        unimplemented!()
+    }
+}
+fn main() {}
diff --git a/src/test/ui/wf/hir-wf-check-erase-regions.stderr b/src/test/ui/wf/hir-wf-check-erase-regions.stderr
new file mode 100644
index 00000000000..203f09994e6
--- /dev/null
+++ b/src/test/ui/wf/hir-wf-check-erase-regions.stderr
@@ -0,0 +1,31 @@
+error[E0277]: `&T` is not an iterator
+  --> $DIR/hir-wf-check-erase-regions.rs:7:5
+   |
+LL |     type IntoIter = std::iter::Flatten<std::slice::Iter<'a, T>>;
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ `&T` is not an iterator
+   | 
+  ::: $SRC_DIR/core/src/iter/adapters/flatten.rs:LL:COL
+   |
+LL | pub struct Flatten<I: Iterator<Item: IntoIterator>> {
+   |                                      ------------ required by this bound in `Flatten`
+   |
+   = help: the trait `Iterator` is not implemented for `&T`
+   = note: required because of the requirements on the impl of `IntoIterator` for `&T`
+
+error[E0277]: `&T` is not an iterator
+  --> $DIR/hir-wf-check-erase-regions.rs:10:27
+   |
+LL |     fn into_iter(self) -> Self::IntoIter {
+   |                           ^^^^^^^^^^^^^^ `&T` is not an iterator
+   | 
+  ::: $SRC_DIR/core/src/iter/adapters/flatten.rs:LL:COL
+   |
+LL | pub struct Flatten<I: Iterator<Item: IntoIterator>> {
+   |                                      ------------ required by this bound in `Flatten`
+   |
+   = help: the trait `Iterator` is not implemented for `&T`
+   = note: required because of the requirements on the impl of `IntoIterator` for `&T`
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0277`.