Validation and other things

compiler/rustc_ast_lowering/src/errors.rs

@@ -414,3 +414,10 @@ pub(crate) struct AsyncBoundOnlyForFnTraits {
     #[primary_span]
     pub span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(ast_lowering_no_precise_captures_on_apit)]
+pub(crate) struct NoPreciseCapturesOnApit {
+    #[primary_span]
+    pub span: Span,
+}