Rollup merge of #105147 - nbdd0121:inline_const_unsafe, r=oli-obk

Allow unsafe through inline const

Handle similar to closures.

Address https://github.com/rust-lang/rust/pull/104087#issuecomment-1324173328

Note that this PR does not fix the issue for `unsafe { [0; function_requiring_unsafe()] }`. This is fundamentally unfixable for MIR unsafeck IMO.

This PR also does not fix unsafety checking for inline const in pattern position. It actually breaks it, allowing unsafe functions to be used in inline const in pattern position without unsafe blocks. Inline const in pattern position is not visible in MIR so ignored by MIR unsafety checking (currently it is also not checked by borrow checker, which is the reason why it's considered an incomplete feature).

`@rustbot` label: +T-lang +F-inline_const

8 files changed, 119 insertions, 0 deletions

diff --git a/src/test/ui/inline-const/expr-unsafe-err.mir.stderr b/src/test/ui/inline-const/expr-unsafe-err.mir.stderr
new file mode 100644
index 00000000000..1bec41e2efa
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe-err.mir.stderr
@@ -0,0 +1,11 @@
+error[E0133]: call to unsafe function is unsafe and requires unsafe function or block
+  --> $DIR/expr-unsafe-err.rs:8:9
+   |
+LL |         require_unsafe();
+   |         ^^^^^^^^^^^^^^^^ call to unsafe function
+   |
+   = note: consult the function's documentation for information on how to avoid undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/inline-const/expr-unsafe-err.rs b/src/test/ui/inline-const/expr-unsafe-err.rs
new file mode 100644
index 00000000000..adf05d352ea
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe-err.rs
@@ -0,0 +1,11 @@
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+#![feature(inline_const)]
+const unsafe fn require_unsafe() -> usize { 1 }
+
+fn main() {
+    const {
+        require_unsafe();
+        //~^ ERROR [E0133]
+    }
+}
diff --git a/src/test/ui/inline-const/expr-unsafe-err.thir.stderr b/src/test/ui/inline-const/expr-unsafe-err.thir.stderr
new file mode 100644
index 00000000000..c971e8afb35
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe-err.thir.stderr
@@ -0,0 +1,11 @@
+error[E0133]: call to unsafe function `require_unsafe` is unsafe and requires unsafe function or block
+  --> $DIR/expr-unsafe-err.rs:8:9
+   |
+LL |         require_unsafe();
+   |         ^^^^^^^^^^^^^^^^ call to unsafe function
+   |
+   = note: consult the function's documentation for information on how to avoid undefined behavior
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0133`.
diff --git a/src/test/ui/inline-const/expr-unsafe.mir.stderr b/src/test/ui/inline-const/expr-unsafe.mir.stderr
new file mode 100644
index 00000000000..1ab6e42fba0
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe.mir.stderr
@@ -0,0 +1,14 @@
+warning: unnecessary `unsafe` block
+  --> $DIR/expr-unsafe.rs:12:13
+   |
+LL |             unsafe {}
+   |             ^^^^^^ unnecessary `unsafe` block
+   |
+note: the lint level is defined here
+  --> $DIR/expr-unsafe.rs:4:9
+   |
+LL | #![warn(unused_unsafe)]
+   |         ^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/inline-const/expr-unsafe.rs b/src/test/ui/inline-const/expr-unsafe.rs
new file mode 100644
index 00000000000..d71efd33db1
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe.rs
@@ -0,0 +1,16 @@
+// check-pass
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+#![warn(unused_unsafe)]
+#![feature(inline_const)]
+const unsafe fn require_unsafe() -> usize { 1 }
+
+fn main() {
+    unsafe {
+        const {
+            require_unsafe();
+            unsafe {}
+            //~^ WARNING unnecessary `unsafe` block
+        }
+    }
+}
diff --git a/src/test/ui/inline-const/expr-unsafe.thir.stderr b/src/test/ui/inline-const/expr-unsafe.thir.stderr
new file mode 100644
index 00000000000..4737444fb61
--- /dev/null
+++ b/src/test/ui/inline-const/expr-unsafe.thir.stderr
@@ -0,0 +1,17 @@
+warning: unnecessary `unsafe` block
+  --> $DIR/expr-unsafe.rs:12:13
+   |
+LL |     unsafe {
+   |     ------ because it's nested under this `unsafe` block
+...
+LL |             unsafe {}
+   |             ^^^^^^ unnecessary `unsafe` block
+   |
+note: the lint level is defined here
+  --> $DIR/expr-unsafe.rs:4:9
+   |
+LL | #![warn(unused_unsafe)]
+   |         ^^^^^^^^^^^^^
+
+warning: 1 warning emitted
+
diff --git a/src/test/ui/inline-const/pat-unsafe-err.rs b/src/test/ui/inline-const/pat-unsafe-err.rs
new file mode 100644
index 00000000000..e290b438c51
--- /dev/null
+++ b/src/test/ui/inline-const/pat-unsafe-err.rs
@@ -0,0 +1,17 @@
+// ignore-test This is currently broken
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
+#![allow(incomplete_features)]
+#![feature(inline_const_pat)]
+
+const unsafe fn require_unsafe() -> usize { 1 }
+
+fn main() {
+    match () {
+        const {
+            require_unsafe();
+            //~^ ERROR [E0133]
+        } => (),
+    }
+}
diff --git a/src/test/ui/inline-const/pat-unsafe.rs b/src/test/ui/inline-const/pat-unsafe.rs
new file mode 100644
index 00000000000..bcf7f6e0180
--- /dev/null
+++ b/src/test/ui/inline-const/pat-unsafe.rs
@@ -0,0 +1,22 @@
+// ignore-test This is currently broken
+// check-pass
+// revisions: mir thir
+// [thir]compile-flags: -Z thir-unsafeck
+
+#![allow(incomplete_features)]
+#![warn(unused_unsafe)]
+#![feature(inline_const_pat)]
+
+const unsafe fn require_unsafe() -> usize { 1 }
+
+fn main() {
+    unsafe {
+        match () {
+            const {
+                require_unsafe();
+                unsafe {}
+                //~^ WARNING unnecessary `unsafe` block
+            } => (),
+        }
+    }
+}