Delay initial cache priming until proc-macros are loaded

Author: Veykril

crates/rust-analyzer/src/main_loop.rs

@@ -452,7 +452,11 @@ impl GlobalState {
                     // Project has loaded properly, kick off initial flycheck
                     self.flycheck.iter().for_each(|flycheck| flycheck.restart_workspace(None));
                 }
-                if self.config.prefill_caches() {
+                // delay initial cache priming until proc macros are loaded, or we will load up a bunch of garbage into salsa
+                let proc_macros_loaded = self.config.prefill_caches()
+                    && !self.config.expand_proc_macros()
+                    || self.fetch_proc_macros_queue.last_op_result().copied().unwrap_or(false);
+                if proc_macros_loaded {
                     self.prime_caches_queue.request_op("became quiescent".to_owned(), ());
                 }
             }