This warnings don't give much benefits for developers. Code completion
UI tends to show them unusable. But usually, developers can modify the
context to accept async calls, e.g. by wrapping it with `Task { }`
rdar://126737530
Store whether a result is async in the `ContextFreeCodeCompletionResult` and determine whether an async method is used in a sync context when promoting the context free result to a contextual result.
rdar://78317170
Generating diagnostics for "not recommended" items requires an
associated declaration. However, cases like this:
func test(fn: (Int) async -> Void) {
fn(#^HERE^#)
}
For the function call pattern item, there's no associated decl because
the callee is an expression. Ideally it should emit a diagnostic, but
for now, to avoid the crash, don't emit diagnostics unless the item has
the associated decl.
rdar://95306033
* Implement 'getDiagnosticSeverity()' and 'getDiagnosticMessage()' on
'CodeCompletionResult'
* Differentiate 'RedundantImportIndirect' from 'RedundantImport'
* Make non-Sendable check respects '-warn-concurrency'
rdar://76129658
