Unnamed repository; edit this file 'description' to name the repository.
fix: Recover from missing argument in call expressions
Previously, when parsing an argument list with a missing argument (e.g.,
`(a, , b)` in `foo(a, , b)`), the parser would stop upon an unexpected
token (at the second comma in the example), resulting in an incorrect
parse tree.
This commit improves error handling in such cases, ensuring a more
accurate parse tree is built.
4 files changed, 53 insertions, 22 deletions
diff --git a/crates/hir-expand/src/fixup.rs b/crates/hir-expand/src/fixup.rs index a3b2c700ff..ed29411a6b 100644 --- a/crates/hir-expand/src/fixup.rs +++ b/crates/hir-expand/src/fixup.rs @@ -632,20 +632,6 @@ fn foo () {a . b ; bar () ;} } #[test] - fn extraneous_comma() { - check( - r#" -fn foo() { - bar(,); -} -"#, - expect![[r#" -fn foo () {__ra_fixup ;} -"#]], - ) - } - - #[test] fn fixup_if_1() { check( r#" diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs index e99c111d39..52a08c4fb1 100644 --- a/crates/parser/src/grammar/expressions.rs +++ b/crates/parser/src/grammar/expressions.rs @@ -611,6 +611,7 @@ fn cast_expr(p: &mut Parser<'_>, lhs: CompletedMarker) -> CompletedMarker { // foo(bar::); // foo(bar:); // foo(bar+); +// foo(a, , b); // } fn arg_list(p: &mut Parser<'_>) { assert!(p.at(T!['('])); @@ -619,14 +620,30 @@ fn arg_list(p: &mut Parser<'_>) { // fn main() { // foo(#[attr] 92) // } - delimited( - p, - T!['('], - T![')'], - T![,], - EXPR_FIRST.union(ATTRIBUTE_FIRST), - |p: &mut Parser<'_>| expr(p).is_some(), - ); + p.bump(T!['(']); + while !p.at(T![')']) && !p.at(EOF) { + if p.at(T![,]) { + // Recover if an argument is missing and only got a delimiter, + // e.g. `(a, , b)`. + p.error("expected expression"); + p.bump(T![,]); + continue; + } + + if expr(p).is_none() { + break; + } + if !p.at(T![,]) { + if p.at_ts(EXPR_FIRST.union(ATTRIBUTE_FIRST)) { + p.error(format!("expected {:?}", T![,])); + } else { + break; + } + } else { + p.bump(T![,]); + } + } + p.expect(T![')']); m.complete(p, ARG_LIST); } diff --git a/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rast b/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rast index 5d0fe859c2..85def9e148 100644 --- a/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rast +++ b/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rast @@ -68,6 +68,32 @@ SOURCE_FILE PLUS "+" R_PAREN ")" SEMICOLON ";" + WHITESPACE "\n " + EXPR_STMT + CALL_EXPR + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "foo" + ARG_LIST + L_PAREN "(" + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + COMMA "," + WHITESPACE " " + COMMA "," + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + R_PAREN ")" + SEMICOLON ";" WHITESPACE "\n" R_CURLY "}" WHITESPACE "\n" @@ -75,3 +101,4 @@ error 25: expected identifier error 39: expected COMMA error 39: expected expression error 55: expected expression +error 68: expected expression diff --git a/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rs b/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rs index 0e7ac9cc30..175a31f8b5 100644 --- a/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rs +++ b/crates/parser/test_data/parser/inline/err/0015_arg_list_recovery.rs @@ -2,4 +2,5 @@ fn main() { foo(bar::); foo(bar:); foo(bar+); + foo(a, , b); } |