Auto merge of rust-lang#15438 - Veykril:eager-parser-stuck, r=Veykril

fix: Fix parser being stuck in eager macro inputs

Fixes rust-lang/rust-analyzer#15437

Author: bors

crates/hir-def/src/body/lower.rs

@@ -505,6 +505,9 @@ impl ExprCollector<'_> {
                 let mut args = Vec::new();
                 let mut arg_types = Vec::new();
                 if let Some(pl) = e.param_list() {
+                    let num_params = pl.params().count();
+                    args.reserve_exact(num_params);
+                    arg_types.reserve_exact(num_params);
                     for param in pl.params() {
                         let pat = this.collect_pat_top(param.pat());
                         let type_ref =

crates/hir-def/src/macro_expansion_tests/builtin_fn_macro.rs

@@ -238,7 +238,7 @@ fn main() {
     /* error: expected expression */;
     /* error: expected expression, expected COMMA */;
     /* error: expected expression */::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::ArgumentV1::new(&(), ::core::fmt::Display::fmt), ]);
-    /* error: expected expression, expected expression */;
+    /* error: expected expression, expected R_PAREN */;
     ::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::ArgumentV1::new(&(5), ::core::fmt::Display::fmt), ]);
 }
 "##]],

crates/hir-def/src/macro_expansion_tests/mbe/regression.rs

@@ -936,3 +936,41 @@ fn main() {
 "##]],
     );
 }
+
+#[test]
+fn eager_regression_154032() {
+    check(
+        r#"
+#[rustc_builtin_macro]
+#[macro_export]
+macro_rules! format_args {}
+
+fn main() {
+    format_args /* +errors */ !("{}", &[0 2]);
+}
+
+"#,
+        expect![[r##"
+#[rustc_builtin_macro]
+#[macro_export]
+macro_rules! format_args {}
+
+fn main() {
+    /* error: expected COMMA, expected R_BRACK, expected COMMA, expected COMMA, expected expression, expected R_PAREN *//* parse error: expected COMMA */
+/* parse error: expected R_BRACK */
+/* parse error: expected COMMA */
+/* parse error: expected COMMA */
+/* parse error: expected expression */
+/* parse error: expected R_PAREN */
+/* parse error: expected R_PAREN */
+/* parse error: expected expression, item or let statement */
+/* parse error: expected expression, item or let statement */
+/* parse error: expected expression, item or let statement */
+/* parse error: expected expression, item or let statement */
+/* parse error: expected expression, item or let statement */
+::core::fmt::Arguments::new_v1(&["", ], &[::core::fmt::ArgumentV1::new(&(&[0 2]), ::core::fmt::Display::fmt), ]);
+}
+
+"##]],
+    );
+}

crates/parser/src/grammar.rs

@@ -184,7 +184,9 @@ pub(crate) mod entry {
             };
             p.bump_any();
             while !p.at(EOF) && !p.at(closing_paren_kind) {
-                expressions::expr(p);
+                if expressions::expr(p).is_none() {
+                    break;
+                }
                 if !p.at(EOF) && !p.at(closing_paren_kind) {
                     p.expect(T![,]);
                 }