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Auto merge of #15212 - lowr:patch/recover-from-incomplete-assoc-ty, r=HKalbasi
Recover from missing associated items and generic const defaults
Fixes #15129
6 files changed, 113 insertions, 3 deletions
diff --git a/crates/parser/src/grammar/generic_args.rs b/crates/parser/src/grammar/generic_args.rs index e589b69934..211af98e6e 100644 --- a/crates/parser/src/grammar/generic_args.rs +++ b/crates/parser/src/grammar/generic_args.rs @@ -32,6 +32,9 @@ const GENERIC_ARG_FIRST: TokenSet = TokenSet::new(&[ ]) .union(types::TYPE_FIRST); +// Despite its name, it can also be used for generic param list. +const GENERIC_ARG_RECOVERY_SET: TokenSet = TokenSet::new(&[T![>], T![,]]); + // test generic_arg // type T = S<i32>; fn generic_arg(p: &mut Parser<'_>) -> bool { @@ -55,6 +58,15 @@ fn generic_arg(p: &mut Parser<'_>) -> bool { // test assoc_type_eq // type T = StreamingIterator<Item<'a> = &'a T>; types::type_(p); + } else if p.at_ts(GENERIC_ARG_RECOVERY_SET) { + // Although `const_arg()` recovers as expected, we want to + // handle those here to give the following message because + // we don't know whether this associated item is a type or + // const at this point. + + // test_err recover_from_missing_assoc_item_binding + // fn f() -> impl Iterator<Item = , Item = > {} + p.error("missing associated item binding"); } else { // test assoc_const_eq // fn foo<F: Foo<N=3>>() {} @@ -141,12 +153,17 @@ pub(super) fn const_arg_expr(p: &mut Parser<'_>) { expressions::literal(p); lm.complete(p, PREFIX_EXPR); } - _ => { + _ if paths::is_use_path_start(p) => { // This shouldn't be hit by `const_arg` let lm = p.start(); paths::use_path(p); lm.complete(p, PATH_EXPR); } + _ => { + // test_err recover_from_missing_const_default + // struct A<const N: i32 = , const M: i32 =>; + p.err_recover("expected a generic const argument", GENERIC_ARG_RECOVERY_SET); + } } } diff --git a/crates/parser/src/grammar/generic_params.rs b/crates/parser/src/grammar/generic_params.rs index 7fcf938bab..8ed1c84c4c 100644 --- a/crates/parser/src/grammar/generic_params.rs +++ b/crates/parser/src/grammar/generic_params.rs @@ -79,10 +79,9 @@ fn const_param(p: &mut Parser<'_>, m: Marker) { p.error("missing type for const parameter"); } - if p.at(T![=]) { + if p.eat(T![=]) { // test const_param_default_literal // struct A<const N: i32 = -1>; - p.bump(T![=]); // test const_param_default_expression // struct A<const N: i32 = { 1 }>; diff --git a/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rast b/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rast new file mode 100644 index 0000000000..fc59db84e7 --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rast @@ -0,0 +1,48 @@ +SOURCE_FILE + FN + FN_KW "fn" + WHITESPACE " " + NAME + IDENT "f" + PARAM_LIST + L_PAREN "(" + R_PAREN ")" + WHITESPACE " " + RET_TYPE + THIN_ARROW "->" + WHITESPACE " " + IMPL_TRAIT_TYPE + IMPL_KW "impl" + WHITESPACE " " + TYPE_BOUND_LIST + TYPE_BOUND + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "Iterator" + GENERIC_ARG_LIST + L_ANGLE "<" + ASSOC_TYPE_ARG + NAME_REF + IDENT "Item" + WHITESPACE " " + EQ "=" + WHITESPACE " " + COMMA "," + WHITESPACE " " + ASSOC_TYPE_ARG + NAME_REF + IDENT "Item" + WHITESPACE " " + EQ "=" + WHITESPACE " " + R_ANGLE ">" + WHITESPACE " " + BLOCK_EXPR + STMT_LIST + L_CURLY "{" + R_CURLY "}" + WHITESPACE "\n" +error 30: missing associated item binding +error 39: missing associated item binding diff --git a/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rs b/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rs new file mode 100644 index 0000000000..e484e433a0 --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0021_recover_from_missing_assoc_item_binding.rs @@ -0,0 +1 @@ +fn f() -> impl Iterator<Item = , Item = > {} diff --git a/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rast b/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rast new file mode 100644 index 0000000000..809ad1b8d5 --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rast @@ -0,0 +1,44 @@ +SOURCE_FILE + STRUCT + STRUCT_KW "struct" + WHITESPACE " " + NAME + IDENT "A" + GENERIC_PARAM_LIST + L_ANGLE "<" + CONST_PARAM + CONST_KW "const" + WHITESPACE " " + NAME + IDENT "N" + COLON ":" + WHITESPACE " " + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "i32" + WHITESPACE " " + EQ "=" + WHITESPACE " " + COMMA "," + WHITESPACE " " + CONST_PARAM + CONST_KW "const" + WHITESPACE " " + NAME + IDENT "M" + COLON ":" + WHITESPACE " " + PATH_TYPE + PATH + PATH_SEGMENT + NAME_REF + IDENT "i32" + WHITESPACE " " + EQ "=" + R_ANGLE ">" + SEMICOLON ";" + WHITESPACE "\n" +error 23: expected a generic const argument +error 40: expected a generic const argument diff --git a/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rs b/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rs new file mode 100644 index 0000000000..5bab13da92 --- /dev/null +++ b/crates/parser/test_data/parser/inline/err/0022_recover_from_missing_const_default.rs @@ -0,0 +1 @@ +struct A<const N: i32 = , const M: i32 =>; 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