a0215d8e46
Fundamentally, we have *three* disjoint categories of functions: 1. const-stable functions 2. private/unstable functions that are meant to be callable from const-stable functions 3. functions that can make use of unstable const features This PR implements the following system: - `#[rustc_const_stable]` puts functions in the first category. It may only be applied to `#[stable]` functions. - `#[rustc_const_unstable]` by default puts functions in the third category. The new attribute `#[rustc_const_stable_indirect]` can be added to such a function to move it into the second category. - `const fn` without a const stability marker are in the second category if they are still unstable. They automatically inherit the feature gate for regular calls, it can now also be used for const-calls. Also, several holes in recursive const stability checking are being closed. There's still one potential hole that is hard to avoid, which is when MIR building automatically inserts calls to a particular function in stable functions -- which happens in the panic machinery. Those need to *not* be `rustc_const_unstable` (or manually get a `rustc_const_stable_indirect`) to be sure they follow recursive const stability. But that's a fairly rare and special case so IMO it's fine. The net effect of this is that a `#[unstable]` or unmarked function can be constified simply by marking it as `const fn`, and it will then be const-callable from stable `const fn` and subject to recursive const stability requirements. If it is publicly reachable (which implies it cannot be unmarked), it will be const-unstable under the same feature gate. Only if the function ever becomes `#[stable]` does it need a `#[rustc_const_unstable]` or `#[rustc_const_stable]` marker to decide if this should also imply const-stability. Adding `#[rustc_const_unstable]` is only needed for (a) functions that need to use unstable const lang features (including intrinsics), or (b) `#[stable]` functions that are not yet intended to be const-stable. Adding `#[rustc_const_stable]` is only needed for functions that are actually meant to be directly callable from stable const code. `#[rustc_const_stable_indirect]` is used to mark intrinsics as const-callable and for `#[rustc_const_unstable]` functions that are actually called from other, exposed-on-stable `const fn`. No other attributes are required.
125 lines
4.0 KiB
Plaintext
125 lines
4.0 KiB
Plaintext
attr_cfg_predicate_identifier =
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`cfg` predicate key must be an identifier
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attr_deprecated_item_suggestion =
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suggestions on deprecated items are unstable
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.help = add `#![feature(deprecated_suggestion)]` to the crate root
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.note = see #94785 for more details
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attr_expected_one_cfg_pattern =
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expected 1 cfg-pattern
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attr_expected_single_version_literal =
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expected single version literal
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attr_expected_version_literal =
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expected a version literal
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attr_expects_feature_list =
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`{$name}` expects a list of feature names
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attr_expects_features =
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`{$name}` expects feature names
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attr_incorrect_meta_item =
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incorrect meta item
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attr_incorrect_repr_format_align_one_arg =
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incorrect `repr(align)` attribute format: `align` takes exactly one argument in parentheses
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attr_incorrect_repr_format_expect_literal_integer =
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incorrect `repr(align)` attribute format: `align` expects a literal integer as argument
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attr_incorrect_repr_format_generic =
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incorrect `repr({$repr_arg})` attribute format
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.suggestion = use parentheses instead
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attr_incorrect_repr_format_packed_expect_integer =
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incorrect `repr(packed)` attribute format: `packed` expects a literal integer as argument
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attr_incorrect_repr_format_packed_one_or_zero_arg =
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incorrect `repr(packed)` attribute format: `packed` takes exactly one parenthesized argument, or no parentheses at all
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attr_invalid_issue_string =
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`issue` must be a non-zero numeric string or "none"
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.must_not_be_zero = `issue` must not be "0", use "none" instead
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.empty = cannot parse integer from empty string
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.invalid_digit = invalid digit found in string
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.pos_overflow = number too large to fit in target type
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.neg_overflow = number too small to fit in target type
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attr_invalid_predicate =
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invalid predicate `{$predicate}`
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attr_invalid_repr_align_need_arg =
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invalid `repr(align)` attribute: `align` needs an argument
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.suggestion = supply an argument here
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attr_invalid_repr_generic =
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invalid `repr({$repr_arg})` attribute: {$error_part}
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attr_invalid_repr_hint_no_paren =
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invalid representation hint: `{$name}` does not take a parenthesized argument list
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attr_invalid_repr_hint_no_value =
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invalid representation hint: `{$name}` does not take a value
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attr_invalid_since =
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'since' must be a Rust version number, such as "1.31.0"
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attr_missing_feature =
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missing 'feature'
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attr_missing_issue =
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missing 'issue'
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attr_missing_note =
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missing 'note'
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attr_missing_since =
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missing 'since'
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attr_multiple_item =
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multiple '{$item}' items
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attr_multiple_stability_levels =
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multiple stability levels
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attr_non_ident_feature =
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'feature' is not an identifier
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attr_rustc_allowed_unstable_pairing =
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`rustc_allowed_through_unstable_modules` attribute must be paired with a `stable` attribute
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attr_rustc_const_stable_indirect_pairing =
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`const_stable_indirect` attribute does not make sense on `rustc_const_stable` function, its behavior is already implied
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attr_rustc_promotable_pairing =
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`rustc_promotable` attribute must be paired with either a `rustc_const_unstable` or a `rustc_const_stable` attribute
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attr_soft_no_args =
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`soft` should not have any arguments
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attr_unknown_meta_item =
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unknown meta item '{$item}'
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.label = expected one of {$expected}
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attr_unknown_version_literal =
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unknown version literal format, assuming it refers to a future version
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attr_unstable_cfg_target_compact =
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compact `cfg(target(..))` is experimental and subject to change
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attr_unsupported_literal_cfg_boolean =
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literal in `cfg` predicate value must be a boolean
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attr_unsupported_literal_cfg_string =
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literal in `cfg` predicate value must be a string
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attr_unsupported_literal_deprecated_kv_pair =
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item in `deprecated` must be a key/value pair
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attr_unsupported_literal_deprecated_string =
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literal in `deprecated` value must be a string
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attr_unsupported_literal_generic =
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unsupported literal
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attr_unsupported_literal_suggestion =
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consider removing the prefix
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