AotPrep collections_hot matmul tuning and bench tweaks

src/runner/modes/llvm.rs

@@ -66,6 +66,18 @@ impl NyashRunner {
             Ok(ast) => ast,
             Err(e) => {
                 eprintln!("❌ Parse error in {}: {}", filename, e);
+                // Enhanced context: list merged prelude files if any (from text-merge path)
+                let preludes = crate::runner::modes::common_util::resolve::clone_last_merged_preludes();
+                if !preludes.is_empty() {
+                    eprintln!("[parse/context] merged prelude files ({}):", preludes.len());
+                    let show = std::cmp::min(16, preludes.len());
+                    for p in preludes.iter().take(show) {
+                        eprintln!("  - {}", p);
+                    }
+                    if preludes.len() > show {
+                        eprintln!("  ... ({} more)", preludes.len() - show);
+                    }
+                }
                 process::exit(1);
             }
         };