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Merged
merged 2 commits into from
Oct 9, 2025
Merged

Improve parsing error for static and const #20805

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216db6d
Improve parsing error for `static` and `const`
A4-Tacks Oct 6, 2025
2707cf7
Allow generic_param_list for `static` items
A4-Tacks Oct 9, 2025
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27 changes: 17 additions & 10 deletions crates/parser/src/grammar/items/consts.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -25,21 +25,28 @@ fn const_or_static(p: &mut Parser<'_>, m: Marker, is_const: bool) {
}

// FIXME: Recover on statics with generic params/where clause.
if is_const {
// test generic_const
// const C<i32>: u32 = 0;
// impl Foo {
// const C<'a>: &'a () = &();
// }
generic_params::opt_generic_param_list(p);
if !is_const && p.at(T![<]) {
// test_err generic_static
// static C<i32>: u32 = 0;
p.error("`static` may not have generic parameters");
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I think it's preferable to eat generic params here, or even better, call opt_generic_params() unconditionally, and just err before for statics. This will also allow us to simplify the next if.

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@A4-Tacks A4-Tacks Oct 9, 2025 •
edited
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Should the AST of a static item contain GENERIC_PARAM_LIST?

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It causes no harm.

}
// test_err generic_static
// static C<i32>: u32 = 0;
// test generic_const
// const C<i32>: u32 = 0;
// impl Foo {
// const C<'a>: &'a () = &();
// }
generic_params::opt_generic_param_list(p);

if p.at(T![:]) {
types::ascription(p);
} else if is_const {
// test_err missing_const_type
// const C = 0;
p.error("missing type for `const`");
} else {
p.error("missing type for `const` or `static`");
// test_err missing_static_type
// static C = 0;
p.error("missing type for `static`");
}
if p.eat(T![=]) {
expressions::expr(p);
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8 changes: 8 additions & 0 deletions crates/parser/test_data/generated/runner.rs
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Expand Up @@ -824,10 +824,18 @@ mod err {
run_and_expect_errors("test_data/parser/inline/err/misplaced_label_err.rs");
}
#[test]
fn missing_const_type() {
run_and_expect_errors("test_data/parser/inline/err/missing_const_type.rs");
}
#[test]
fn missing_fn_param_type() {
run_and_expect_errors("test_data/parser/inline/err/missing_fn_param_type.rs");
}
#[test]
fn missing_static_type() {
run_and_expect_errors("test_data/parser/inline/err/missing_static_type.rs");
}
#[test]
fn path_item_without_excl() {
run_and_expect_errors("test_data/parser/inline/err/path_item_without_excl.rs");
}
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2 changes: 1 addition & 1 deletion crates/parser/test_data/parser/err/0044_item_modifiers.rast
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Expand Up @@ -42,7 +42,7 @@ SOURCE_FILE
WHITESPACE "\n"
error 6: expected fn, trait or impl
error 38: expected a name
error 40: missing type for `const` or `static`
error 40: missing type for `const`
error 40: expected SEMICOLON
error 44: expected an item
error 44: expected an item
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47 changes: 16 additions & 31 deletions crates/parser/test_data/parser/inline/err/generic_static.rast
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Expand Up @@ -4,39 +4,24 @@ SOURCE_FILE
WHITESPACE " "
NAME
IDENT "C"
ERROR
L_ANGLE "<"
ERROR
PATH
PATH_SEGMENT
NAME_REF
GENERIC_PARAM_LIST
L_ANGLE "<"
TYPE_PARAM
NAME
IDENT "i32"
ERROR
R_ANGLE ">"
ERROR
R_ANGLE ">"
COLON ":"
WHITESPACE " "
ERROR
PATH
PATH_SEGMENT
NAME_REF
IDENT "u32"
WHITESPACE " "
ERROR
WHITESPACE " "
PATH_TYPE
PATH
PATH_SEGMENT
NAME_REF
IDENT "u32"
WHITESPACE " "
EQ "="
WHITESPACE " "
ERROR
INT_NUMBER "0"
ERROR
WHITESPACE " "
LITERAL
INT_NUMBER "0"
SEMICOLON ";"
WHITESPACE "\n"
error 8: missing type for `const` or `static`
error 8: expected SEMICOLON
error 8: expected an item
error 12: expected an item
error 12: expected an item
error 13: expected an item
error 18: expected an item
error 19: expected an item
error 21: expected an item
error 22: expected an item
error 8: `static` may not have generic parameters
14 changes: 14 additions & 0 deletions crates/parser/test_data/parser/inline/err/missing_const_type.rast
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@@ -0,0 +1,14 @@
SOURCE_FILE
CONST
CONST_KW "const"
WHITESPACE " "
NAME
IDENT "C"
WHITESPACE " "
EQ "="
WHITESPACE " "
LITERAL
INT_NUMBER "0"
SEMICOLON ";"
WHITESPACE "\n"
error 7: missing type for `const`
1 change: 1 addition & 0 deletions crates/parser/test_data/parser/inline/err/missing_const_type.rs
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@@ -0,0 +1 @@
const C = 0;
14 changes: 14 additions & 0 deletions crates/parser/test_data/parser/inline/err/missing_static_type.rast
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@@ -0,0 +1,14 @@
SOURCE_FILE
STATIC
STATIC_KW "static"
WHITESPACE " "
NAME
IDENT "C"
WHITESPACE " "
EQ "="
WHITESPACE " "
LITERAL
INT_NUMBER "0"
SEMICOLON ";"
WHITESPACE "\n"
error 8: missing type for `static`
1 change: 1 addition & 0 deletions crates/parser/test_data/parser/inline/err/missing_static_type.rs
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@@ -0,0 +1 @@
static C = 0;