ignore assertions-on-constants in const contexts

Author: tesuji

clippy_lints/src/assertions_on_constants.rs

@@ -1,5 +1,6 @@
 use clippy_utils::consts::{constant_with_source, Constant, ConstantSource};
 use clippy_utils::diagnostics::span_lint_and_help;
+use clippy_utils::is_inside_always_const_context;
 use clippy_utils::macros::{find_assert_args, root_macro_call_first_node, PanicExpn};
 use rustc_hir::{Expr, Item, ItemKind, Node};
 use rustc_lint::{LateContext, LateLintPass};
@@ -31,6 +32,10 @@ declare_lint_pass!(AssertionsOnConstants => [ASSERTIONS_ON_CONSTANTS]);
 
 impl<'tcx> LateLintPass<'tcx> for AssertionsOnConstants {
     fn check_expr(&mut self, cx: &LateContext<'tcx>, e: &'tcx Expr<'_>) {
+        if is_inside_always_const_context(cx.tcx, e.hir_id) {
+            return;
+        }
+
         let Some(macro_call) = root_macro_call_first_node(cx, e) else {
             return;
         };

tests/ui/assertions_on_constants.rs

@@ -47,7 +47,6 @@ fn main() {
     assert!(!CFG_FLAG);
 
     const _: () = assert!(true);
-    //~^ ERROR: `assert!(true)` will be optimized out by the compiler
 
     // Don't lint if the value is dependent on a defined constant:
     const N: usize = 1024;

tests/ui/assertions_on_constants.stderr

@@ -72,29 +72,5 @@ LL |     debug_assert!(true);
    |
    = help: remove it
 
-error: `assert!(true)` will be optimized out by the compiler
-  --> tests/ui/assertions_on_constants.rs:49:19
-   |
-LL |     const _: () = assert!(true);
-   |                   ^^^^^^^^^^^^^
-   |
-   = help: remove it
-
-error: `assert!(true)` will be optimized out by the compiler
-  --> tests/ui/assertions_on_constants.rs:59:5
-   |
-LL |     assert!(true);
-   |     ^^^^^^^^^^^^^
-   |
-   = help: remove it
-
-error: `assert!(true)` will be optimized out by the compiler
-  --> tests/ui/assertions_on_constants.rs:60:5
-   |
-LL |     assert!(8 == (7 + 1));
-   |     ^^^^^^^^^^^^^^^^^^^^^
-   |
-   = help: remove it
-
-error: aborting due to 12 previous errors
+error: aborting due to 9 previous errors