Add test cases

tests/ui/inline-const/cross_const_control_flow.rs

@@ -0,0 +1,46 @@
+//@edition:2021
+
+fn foo() {
+    const { return }
+    //~^ ERROR: return statement outside of function body
+}
+
+fn labelled_block_break() {
+    'a: { const { break 'a } }
+    //~^ ERROR: `break` outside of a loop or labeled block
+    //~| ERROR: use of unreachable label
+}
+
+fn loop_break() {
+    loop {
+        const { break }
+        //~^ ERROR: `break` outside of a loop or labeled block
+    }
+}
+
+fn continue_to_labelled_block() {
+    'a: { const { continue 'a } }
+    //~^ ERROR: `continue` outside of a loop
+    //~| ERROR: use of unreachable label
+}
+
+fn loop_continue() {
+    loop {
+        const { continue }
+        //~^ ERROR: `continue` outside of a loop
+    }
+}
+
+async fn await_across_const_block() {
+    const { async {}.await }
+    //~^ ERROR: `await` is only allowed inside `async` functions and blocks
+}
+
+fn reference_to_non_constant_in_const_block() {
+    let x = 1;
+    const { &x };
+    //~^ ERROR: attempt to use a non-constant value in a constant
+}
+
+
+fn main() {}

tests/ui/inline-const/cross_const_control_flow.stderr

@@ -0,0 +1,78 @@
+error[E0767]: use of unreachable label `'a`
+  --> $DIR/cross_const_control_flow.rs:9:25
+   |
+LL |     'a: { const { break 'a } }
+   |     --                  ^^ unreachable label `'a`
+   |     |
+   |     unreachable label defined here
+   |
+   = note: labels are unreachable through functions, closures, async blocks and modules
+
+error[E0767]: use of unreachable label `'a`
+  --> $DIR/cross_const_control_flow.rs:22:28
+   |
+LL |     'a: { const { continue 'a } }
+   |     --                     ^^ unreachable label `'a`
+   |     |
+   |     unreachable label defined here
+   |
+   = note: labels are unreachable through functions, closures, async blocks and modules
+
+error[E0435]: attempt to use a non-constant value in a constant
+  --> $DIR/cross_const_control_flow.rs:41:14
+   |
+LL |     const { &x };
+   |              ^ non-constant value
+   |
+help: consider using `const` instead of `let`
+   |
+LL |     const x: /* Type */ = 1;
+   |     ~~~~~  ++++++++++++
+
+error[E0728]: `await` is only allowed inside `async` functions and blocks
+  --> $DIR/cross_const_control_flow.rs:35:22
+   |
+LL |     const { async {}.await }
+   |           -----------^^^^^--
+   |           |          |
+   |           |          only allowed inside `async` functions and blocks
+   |           this is not `async`
+
+error[E0268]: `break` outside of a loop or labeled block
+  --> $DIR/cross_const_control_flow.rs:9:19
+   |
+LL |     'a: { const { break 'a } }
+   |                   ^^^^^^^^ cannot `break` outside of a loop or labeled block
+
+error[E0268]: `break` outside of a loop or labeled block
+  --> $DIR/cross_const_control_flow.rs:16:17
+   |
+LL |         const { break }
+   |                 ^^^^^ cannot `break` outside of a loop or labeled block
+
+error[E0268]: `continue` outside of a loop
+  --> $DIR/cross_const_control_flow.rs:22:19
+   |
+LL |     'a: { const { continue 'a } }
+   |                   ^^^^^^^^^^^ cannot `continue` outside of a loop
+
+error[E0268]: `continue` outside of a loop
+  --> $DIR/cross_const_control_flow.rs:29:17
+   |
+LL |         const { continue }
+   |                 ^^^^^^^^ cannot `continue` outside of a loop
+
+error[E0572]: return statement outside of function body
+  --> $DIR/cross_const_control_flow.rs:4:13
+   |
+LL | / fn foo() {
+LL | |     const { return }
+   | |           --^^^^^^-- the return is part of this body...
+LL | |
+LL | | }
+   | |_- ...not the enclosing function body
+
+error: aborting due to 9 previous errors
+
+Some errors have detailed explanations: E0268, E0435, E0572, E0728, E0767.
+For more information about an error, try `rustc --explain E0268`.