Rollup merge of #118419 - compiler-errors:await-span2, r=cjgillot

Eagerly return `ExprKind::Err` on `yield`/`await` in wrong coroutine context

This PR does 2 things:
1. Refuses to lower `.await` or `yield` when we are outside of the right coroutine context for the operator. Instead, we lower to `hir::ExprKind::Err`, to silence subsequent redundant errors.
2. Reworks a bit of the span tracking in `LoweringContext` to fix a bad span when we have something like `let x = [0; async_fn().await]` where the `await` is inside of an anon const. The span for the "item" still kinda sucks, since it overlaps with the `await` span, but at least it's accurate.

1 files changed, 0 insertions, 9 deletions

diff --git a/compiler/rustc_passes/src/errors.rs b/compiler/rustc_passes/src/errors.rs
index 411c9410195..58127445322 100644
--- a/compiler/rustc_passes/src/errors.rs
+++ b/compiler/rustc_passes/src/errors.rs
@@ -1005,15 +1005,6 @@ pub struct FeaturePreviouslyDeclared<'a, 'b> {
     pub prev_declared: &'b str,
 }
 
-#[derive(Diagnostic)]
-#[diag(passes_expr_not_allowed_in_context, code = "E0744")]
-pub struct ExprNotAllowedInContext<'a> {
-    #[primary_span]
-    pub span: Span,
-    pub expr: String,
-    pub context: &'a str,
-}
-
 pub struct BreakNonLoop<'a> {
     pub span: Span,
     pub head: Option<Span>,