basic lint v2 implemented

compiler/rustc_lint/src/lints.rs

@@ -900,6 +900,12 @@ pub struct QueryInstability {
     pub query: Symbol,
 }
 
+#[derive(LintDiagnostic)]
+#[diag(lint_span_use_eq_ctxt)]
+pub struct SpanUseEqCtxtDiag<'a> {
+    pub msg: &'a str,
+}
+
 #[derive(LintDiagnostic)]
 #[diag(lint_tykind_kind)]
 pub struct TykindKind {