Cancel emitting FCW lint if it is an edition fixing lint

Author: rylev

compiler/rustc_middle/src/lint.rs

@@ -272,11 +272,13 @@ pub fn struct_lint_level<'s, 'd>(
             // emit shouldn't be automatically fixed by rustfix.
             err.allow_suggestions(false);
 
-            // If this is a future incompatible lint it'll become a hard error, so
-            // we have to emit *something*. Also, if this lint occurs in the
-            // expansion of a macro from an external crate, allow individual lints
-            // to opt-out from being reported.
-            if future_incompatible.is_none() && !lint.report_in_external_macro {
+            // If this is a future incompatible that is not an edition fixing lint
+            // it'll become a hard error, so we have to emit *something*. Also,
+            // if this lint occurs in the expansion of a macro from an external crate,
+            // allow individual lints to opt-out from being reported.
+            let not_future_incompatible =
+                future_incompatible.map(|f| f.edition.is_some()).unwrap_or(true);
+            if not_future_incompatible && !lint.report_in_external_macro {
                 err.cancel();
                 // Don't continue further, since we don't want to have
                 // `diag_span_note_once` called for a diagnostic that isn't emitted.