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Auto merge of #16124 - ohno418:call-expr-missing-arg, r=Veykril
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.
---
Fixes https://github.com/rust-lang/rust-analyzer/issues/15683.
16 files changed, 267 insertions, 30 deletions
diff --git a/crates/parser/src/grammar.rs b/crates/parser/src/grammar.rs index 53fda3ae4f..34715628f1 100644 --- a/crates/parser/src/grammar.rs +++ b/crates/parser/src/grammar.rs @@ -393,11 +393,26 @@ fn delimited( bra: SyntaxKind, ket: SyntaxKind, delim: SyntaxKind, + unexpected_delim_message: impl Fn() -> String, first_set: TokenSet, mut parser: impl FnMut(&mut Parser<'_>) -> bool, ) { p.bump(bra); while !p.at(ket) && !p.at(EOF) { + if p.at(delim) { + // Recover if an argument is missing and only got a delimiter, + // e.g. `(a, , b)`. + + // Wrap the erroneous delimiter in an error node so that fixup logic gets rid of it. + // FIXME: Ideally this should be handled in fixup in a structured way, but our list + // nodes currently have no concept of a missing node between two delimiters. + // So doing it this way is easier. + let m = p.start(); + p.error(unexpected_delim_message()); + p.bump(delim); + m.complete(p, ERROR); + continue; + } if !parser(p) { break; } diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs index e99c111d39..f40c515fa0 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!['('])); @@ -624,8 +625,9 @@ fn arg_list(p: &mut Parser<'_>) { T!['('], T![')'], T![,], + || "expected expression".into(), EXPR_FIRST.union(ATTRIBUTE_FIRST), - |p: &mut Parser<'_>| expr(p).is_some(), + |p| expr(p).is_some(), ); m.complete(p, ARG_LIST); } diff --git a/crates/parser/src/grammar/generic_args.rs b/crates/parser/src/grammar/generic_args.rs index 211af98e6e..249be2a333 100644 --- a/crates/parser/src/grammar/generic_args.rs +++ b/crates/parser/src/grammar/generic_args.rs @@ -1,5 +1,7 @@ use super::*; +// test_err generic_arg_list_recover +// type T = T<0, ,T>; pub(super) fn opt_generic_arg_list(p: &mut Parser<'_>, colon_colon_required: bool) { let m; if p.at(T![::]) && p.nth(2) == T![<] { @@ -11,7 +13,15 @@ pub(super) fn opt_generic_arg_list(p: &mut Parser<'_>, colon_colon_required: boo return; } - delimited(p, T![<], T![>], T![,], GENERIC_ARG_FIRST, generic_arg); + delimited( + p, + T![<], + T![>], + T![,], + || "expected generic argument".into(), + GENERIC_ARG_FIRST, + generic_arg, + ); m.complete(p, GENERIC_ARG_LIST); } diff --git a/crates/parser/src/grammar/generic_params.rs b/crates/parser/src/grammar/generic_params.rs index 29d9b05d3f..3c577aa3cb 100644 --- a/crates/parser/src/grammar/generic_params.rs +++ b/crates/parser/src/grammar/generic_params.rs @@ -10,16 +10,27 @@ pub(super) fn opt_generic_param_list(p: &mut Parser<'_>) { // test generic_param_list // fn f<T: Clone>() {} + +// test_err generic_param_list_recover +// fn f<T: Clone,, U:, V>() {} fn generic_param_list(p: &mut Parser<'_>) { assert!(p.at(T![<])); let m = p.start(); - delimited(p, T![<], T![>], T![,], GENERIC_PARAM_FIRST.union(ATTRIBUTE_FIRST), |p| { - // test generic_param_attribute - // fn foo<#[lt_attr] 'a, #[t_attr] T>() {} - let m = p.start(); - attributes::outer_attrs(p); - generic_param(p, m) - }); + delimited( + p, + T![<], + T![>], + T![,], + || "expected generic parameter".into(), + GENERIC_PARAM_FIRST.union(ATTRIBUTE_FIRST), + |p| { + // test generic_param_attribute + // fn foo<#[lt_attr] 'a, #[t_attr] T>() {} + let m = p.start(); + attributes::outer_attrs(p); + generic_param(p, m) + }, + ); m.complete(p, GENERIC_PARAM_LIST); } diff --git a/crates/parser/src/grammar/items/adt.rs b/crates/parser/src/grammar/items/adt.rs index 17f41b8e13..21078175c0 100644 --- a/crates/parser/src/grammar/items/adt.rs +++ b/crates/parser/src/grammar/items/adt.rs @@ -146,28 +146,39 @@ pub(crate) fn record_field_list(p: &mut Parser<'_>) { const TUPLE_FIELD_FIRST: TokenSet = types::TYPE_FIRST.union(ATTRIBUTE_FIRST).union(VISIBILITY_FIRST); +// test_err tuple_field_list_recovery +// struct S(struct S; +// struct S(A,,B); fn tuple_field_list(p: &mut Parser<'_>) { assert!(p.at(T!['('])); let m = p.start(); - delimited(p, T!['('], T![')'], T![,], TUPLE_FIELD_FIRST, |p| { - let m = p.start(); - // test tuple_field_attrs - // struct S (#[attr] f32); - attributes::outer_attrs(p); - let has_vis = opt_visibility(p, true); - if !p.at_ts(types::TYPE_FIRST) { - p.error("expected a type"); - if has_vis { - m.complete(p, ERROR); - } else { - m.abandon(p); + delimited( + p, + T!['('], + T![')'], + T![,], + || "expected tuple field".into(), + TUPLE_FIELD_FIRST, + |p| { + let m = p.start(); + // test tuple_field_attrs + // struct S (#[attr] f32); + attributes::outer_attrs(p); + let has_vis = opt_visibility(p, true); + if !p.at_ts(types::TYPE_FIRST) { + p.error("expected a type"); + if has_vis { + m.complete(p, ERROR); + } else { + m.abandon(p); + } + return false; } - return false; - } - types::type_(p); - m.complete(p, TUPLE_FIELD); - true - }); + types::type_(p); + m.complete(p, TUPLE_FIELD); + true + }, + ); m.complete(p, TUPLE_FIELD_LIST); } diff --git a/crates/parser/src/grammar/items/use_item.rs b/crates/parser/src/grammar/items/use_item.rs index f689c06b31..675a1fd465 100644 --- a/crates/parser/src/grammar/items/use_item.rs +++ b/crates/parser/src/grammar/items/use_item.rs @@ -93,9 +93,16 @@ pub(crate) fn use_tree_list(p: &mut Parser<'_>) { // use b; // struct T; // fn test() {} - delimited(p, T!['{'], T!['}'], T![,], USE_TREE_LIST_FIRST_SET, |p: &mut Parser<'_>| { - use_tree(p, false) || p.at_ts(USE_TREE_LIST_RECOVERY_SET) - }); + // use {a ,, b}; + delimited( + p, + T!['{'], + T!['}'], + T![,], + || "expected use tree".into(), + USE_TREE_LIST_FIRST_SET, + |p: &mut Parser<'_>| use_tree(p, false) || p.at_ts(USE_TREE_LIST_RECOVERY_SET), + ); m.complete(p, USE_TREE_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..cd5aa680c6 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 +68,33 @@ 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 " " + ERROR + COMMA "," + WHITESPACE " " + PATH_EXPR + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + R_PAREN ")" + SEMICOLON ";" WHITESPACE "\n" R_CURLY "}" WHITESPACE "\n" @@ -75,3 +102,4 @@ error 25: expected identifier error 39: expected COMMA error 39: expected expression error 55: expected expression +error 69: 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); } diff --git a/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rast b/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rast index cb90b093ba..b576d872e1 100644 --- a/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rast +++ b/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rast @@ -43,4 +43,29 @@ SOURCE_FILE L_CURLY "{" R_CURLY "}" WHITESPACE "\n" + USE + USE_KW "use" + WHITESPACE " " + USE_TREE + USE_TREE_LIST + L_CURLY "{" + USE_TREE + PATH + PATH_SEGMENT + NAME_REF + IDENT "a" + WHITESPACE " " + COMMA "," + ERROR + COMMA "," + WHITESPACE " " + USE_TREE + PATH + PATH_SEGMENT + NAME_REF + IDENT "b" + R_CURLY "}" + SEMICOLON ";" + WHITESPACE "\n" error 6: expected R_CURLY +error 46: expected use tree diff --git a/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rs b/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rs index f16959c25f..9885e6ab27 100644 --- a/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rs +++ b/crates/parser/test_data/parser/inline/err/0026_use_tree_list_err_recovery.rs @@ -2,3 +2,4 @@ use {a; use b; struct T; fn test() {} +use {a ,, b}; diff --git a/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rast b/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rast new file mode 100644 index 0000000000..6b0bfa007e --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rast @@ -0,0 +1,44 @@ +SOURCE_FILE + STRUCT + STRUCT_KW "struct" + WHITESPACE " " + NAME + IDENT "S" + TUPLE_FIELD_LIST + L_PAREN "(" + STRUCT + STRUCT_KW "struct" + WHITESPACE " " + NAME + IDENT "S" + SEMICOLON ";" + WHITESPACE "\n" + STRUCT + STRUCT_KW "struct" + WHITESPACE " " + NAME + IDENT "S" + TUPLE_FIELD_LIST + L_PAREN "(" + TUPLE_FIELD + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "A" + COMMA "," + ERROR + COMMA "," + TUPLE_FIELD + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "B" + R_PAREN ")" + SEMICOLON ";" + WHITESPACE "\n" +error 9: expected a type +error 9: expected R_PAREN +error 9: expected SEMICOLON +error 30: expected tuple field diff --git a/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rs b/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rs new file mode 100644 index 0000000000..ecb4d8bda1 --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0029_tuple_field_list_recovery.rs @@ -0,0 +1,2 @@ +struct S(struct S; +struct S(A,,B); diff --git a/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rast b/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rast new file mode 100644 index 0000000000..4cf5a3386b --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rast @@ -0,0 +1,33 @@ +SOURCE_FILE + TYPE_ALIAS + TYPE_KW "type" + WHITESPACE " " + NAME + IDENT "T" + WHITESPACE " " + EQ "=" + WHITESPACE " " + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "T" + GENERIC_ARG_LIST + L_ANGLE "<" + CONST_ARG + LITERAL + INT_NUMBER "0" + COMMA "," + WHITESPACE " " + ERROR + COMMA "," + TYPE_ARG + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "T" + R_ANGLE ">" + SEMICOLON ";" + WHITESPACE "\n" +error 14: expected generic argument diff --git a/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rs b/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rs new file mode 100644 index 0000000000..7d849aa1be --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0030_generic_arg_list_recover.rs @@ -0,0 +1 @@ +type T = T<0, ,T>; diff --git a/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rast b/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rast new file mode 100644 index 0000000000..0a1ed01fbe --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rast @@ -0,0 +1,45 @@ +SOURCE_FILE + FN + FN_KW "fn" + WHITESPACE " " + NAME + IDENT "f" + GENERIC_PARAM_LIST + L_ANGLE "<" + TYPE_PARAM + NAME + IDENT "T" + COLON ":" + WHITESPACE " " + TYPE_BOUND_LIST + TYPE_BOUND + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "Clone" + COMMA "," + ERROR + COMMA "," + WHITESPACE " " + TYPE_PARAM + NAME + IDENT "U" + COLON ":" + TYPE_BOUND_LIST + COMMA "," + WHITESPACE " " + TYPE_PARAM + NAME + IDENT "V" + R_ANGLE ">" + PARAM_LIST + L_PAREN "(" + R_PAREN ")" + WHITESPACE " " + BLOCK_EXPR + STMT_LIST + L_CURLY "{" + R_CURLY "}" + WHITESPACE "\n" +error 14: expected generic parameter diff --git a/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rs b/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rs new file mode 100644 index 0000000000..2b5149bb0d --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0031_generic_param_list_recover.rs @@ -0,0 +1 @@ +fn f<T: Clone,, U:, V>() {} |