8df39667dc
This option guards the logic of writing long type names in files and instead using short forms in error messages in rustc_middle/ty/error behind a flag. The main motivation for this change is to disable this behaviour when running ui tests. This logic can be triggered by running tests in a directory that has a long enough path, e.g. /my/very-long-path/where/rust-codebase/exists/ This means ui tests can fail depending on how long the path to their file is. Some ui tests actually rely on this behaviour for their assertions, so for those we enable the flag manually.
370 lines
15 KiB
Rust
370 lines
15 KiB
Rust
use crate::ty::print::{with_forced_trimmed_paths, FmtPrinter, PrettyPrinter};
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use crate::ty::{self, BoundRegionKind, Region, Ty, TyCtxt};
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use rustc_errors::pluralize;
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use rustc_hir as hir;
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use rustc_hir::def::{CtorOf, DefKind};
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use rustc_hir::def_id::DefId;
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use rustc_span::symbol::Symbol;
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use rustc_target::spec::abi;
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use std::borrow::Cow;
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use std::collections::hash_map::DefaultHasher;
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use std::hash::{Hash, Hasher};
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use std::path::PathBuf;
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#[derive(Clone, Copy, Debug, PartialEq, Eq, TypeFoldable, TypeVisitable, Lift)]
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pub struct ExpectedFound<T> {
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pub expected: T,
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pub found: T,
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}
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impl<T> ExpectedFound<T> {
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pub fn new(a_is_expected: bool, a: T, b: T) -> Self {
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if a_is_expected {
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ExpectedFound { expected: a, found: b }
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} else {
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ExpectedFound { expected: b, found: a }
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}
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}
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}
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// Data structures used in type unification
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#[derive(Copy, Clone, Debug, TypeVisitable, Lift, PartialEq, Eq)]
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#[rustc_pass_by_value]
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pub enum TypeError<'tcx> {
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Mismatch,
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ConstnessMismatch(ExpectedFound<ty::BoundConstness>),
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PolarityMismatch(ExpectedFound<ty::ImplPolarity>),
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UnsafetyMismatch(ExpectedFound<hir::Unsafety>),
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AbiMismatch(ExpectedFound<abi::Abi>),
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Mutability,
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ArgumentMutability(usize),
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TupleSize(ExpectedFound<usize>),
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FixedArraySize(ExpectedFound<u64>),
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ArgCount,
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FieldMisMatch(Symbol, Symbol),
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RegionsDoesNotOutlive(Region<'tcx>, Region<'tcx>),
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RegionsInsufficientlyPolymorphic(BoundRegionKind, Region<'tcx>),
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RegionsPlaceholderMismatch,
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Sorts(ExpectedFound<Ty<'tcx>>),
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ArgumentSorts(ExpectedFound<Ty<'tcx>>, usize),
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IntMismatch(ExpectedFound<ty::IntVarValue>),
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FloatMismatch(ExpectedFound<ty::FloatTy>),
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Traits(ExpectedFound<DefId>),
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VariadicMismatch(ExpectedFound<bool>),
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/// Instantiating a type variable with the given type would have
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/// created a cycle (because it appears somewhere within that
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/// type).
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CyclicTy(Ty<'tcx>),
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CyclicConst(ty::Const<'tcx>),
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ProjectionMismatched(ExpectedFound<DefId>),
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ExistentialMismatch(ExpectedFound<&'tcx ty::List<ty::PolyExistentialPredicate<'tcx>>>),
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ConstMismatch(ExpectedFound<ty::Const<'tcx>>),
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IntrinsicCast,
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/// Safe `#[target_feature]` functions are not assignable to safe function pointers.
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TargetFeatureCast(DefId),
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}
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impl TypeError<'_> {
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pub fn involves_regions(self) -> bool {
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match self {
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TypeError::RegionsDoesNotOutlive(_, _)
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| TypeError::RegionsInsufficientlyPolymorphic(_, _)
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| TypeError::RegionsPlaceholderMismatch => true,
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_ => false,
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}
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}
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}
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/// Explains the source of a type err in a short, human readable way. This is meant to be placed
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/// in parentheses after some larger message. You should also invoke `note_and_explain_type_err()`
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/// afterwards to present additional details, particularly when it comes to lifetime-related
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/// errors.
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impl<'tcx> TypeError<'tcx> {
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pub fn to_string(self, tcx: TyCtxt<'tcx>) -> Cow<'static, str> {
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use self::TypeError::*;
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fn report_maybe_different(expected: &str, found: &str) -> String {
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// A naive approach to making sure that we're not reporting silly errors such as:
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// (expected closure, found closure).
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if expected == found {
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format!("expected {}, found a different {}", expected, found)
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} else {
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format!("expected {}, found {}", expected, found)
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}
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}
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match self {
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CyclicTy(_) => "cyclic type of infinite size".into(),
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CyclicConst(_) => "encountered a self-referencing constant".into(),
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Mismatch => "types differ".into(),
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ConstnessMismatch(values) => {
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format!("expected {} bound, found {} bound", values.expected, values.found).into()
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}
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PolarityMismatch(values) => {
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format!("expected {} polarity, found {} polarity", values.expected, values.found)
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.into()
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}
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UnsafetyMismatch(values) => {
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format!("expected {} fn, found {} fn", values.expected, values.found).into()
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}
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AbiMismatch(values) => {
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format!("expected {} fn, found {} fn", values.expected, values.found).into()
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}
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ArgumentMutability(_) | Mutability => "types differ in mutability".into(),
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TupleSize(values) => format!(
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"expected a tuple with {} element{}, found one with {} element{}",
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values.expected,
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pluralize!(values.expected),
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values.found,
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pluralize!(values.found)
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)
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.into(),
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FixedArraySize(values) => format!(
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"expected an array with a fixed size of {} element{}, found one with {} element{}",
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values.expected,
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pluralize!(values.expected),
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values.found,
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pluralize!(values.found)
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)
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.into(),
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ArgCount => "incorrect number of function parameters".into(),
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FieldMisMatch(adt, field) => format!("field type mismatch: {}.{}", adt, field).into(),
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RegionsDoesNotOutlive(..) => "lifetime mismatch".into(),
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// Actually naming the region here is a bit confusing because context is lacking
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RegionsInsufficientlyPolymorphic(..) => {
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"one type is more general than the other".into()
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}
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RegionsPlaceholderMismatch => "one type is more general than the other".into(),
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ArgumentSorts(values, _) | Sorts(values) => {
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let expected = values.expected.sort_string(tcx);
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let found = values.found.sort_string(tcx);
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report_maybe_different(&expected, &found).into()
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}
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Traits(values) => {
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let (mut expected, mut found) = with_forced_trimmed_paths!((
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tcx.def_path_str(values.expected),
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tcx.def_path_str(values.found),
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));
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if expected == found {
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expected = tcx.def_path_str(values.expected);
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found = tcx.def_path_str(values.found);
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}
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report_maybe_different(&format!("trait `{expected}`"), &format!("trait `{found}`"))
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.into()
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}
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IntMismatch(ref values) => {
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let expected = match values.expected {
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ty::IntVarValue::IntType(ty) => ty.name_str(),
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ty::IntVarValue::UintType(ty) => ty.name_str(),
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};
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let found = match values.found {
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ty::IntVarValue::IntType(ty) => ty.name_str(),
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ty::IntVarValue::UintType(ty) => ty.name_str(),
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};
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format!("expected `{}`, found `{}`", expected, found).into()
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}
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FloatMismatch(ref values) => format!(
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"expected `{}`, found `{}`",
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values.expected.name_str(),
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values.found.name_str()
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)
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.into(),
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VariadicMismatch(ref values) => format!(
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"expected {} fn, found {} function",
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if values.expected { "variadic" } else { "non-variadic" },
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if values.found { "variadic" } else { "non-variadic" }
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)
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.into(),
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ProjectionMismatched(ref values) => format!(
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"expected `{}`, found `{}`",
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tcx.def_path_str(values.expected),
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tcx.def_path_str(values.found)
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)
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.into(),
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ExistentialMismatch(ref values) => report_maybe_different(
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&format!("trait `{}`", values.expected),
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&format!("trait `{}`", values.found),
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)
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.into(),
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ConstMismatch(ref values) => {
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format!("expected `{}`, found `{}`", values.expected, values.found).into()
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}
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IntrinsicCast => "cannot coerce intrinsics to function pointers".into(),
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TargetFeatureCast(_) => {
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"cannot coerce functions with `#[target_feature]` to safe function pointers".into()
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}
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}
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}
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}
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impl<'tcx> TypeError<'tcx> {
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pub fn must_include_note(self) -> bool {
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use self::TypeError::*;
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match self {
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CyclicTy(_) | CyclicConst(_) | UnsafetyMismatch(_) | ConstnessMismatch(_)
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| PolarityMismatch(_) | Mismatch | AbiMismatch(_) | FixedArraySize(_)
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| ArgumentSorts(..) | Sorts(_) | IntMismatch(_) | FloatMismatch(_)
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| VariadicMismatch(_) | TargetFeatureCast(_) => false,
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Mutability
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| ArgumentMutability(_)
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| TupleSize(_)
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| ArgCount
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| FieldMisMatch(..)
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| RegionsDoesNotOutlive(..)
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| RegionsInsufficientlyPolymorphic(..)
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| RegionsPlaceholderMismatch
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| Traits(_)
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| ProjectionMismatched(_)
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| ExistentialMismatch(_)
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| ConstMismatch(_)
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| IntrinsicCast => true,
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}
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}
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}
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impl<'tcx> Ty<'tcx> {
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pub fn sort_string(self, tcx: TyCtxt<'tcx>) -> Cow<'static, str> {
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match *self.kind() {
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ty::Foreign(def_id) => format!("extern type `{}`", tcx.def_path_str(def_id)).into(),
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ty::FnDef(def_id, ..) => match tcx.def_kind(def_id) {
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DefKind::Ctor(CtorOf::Struct, _) => "struct constructor".into(),
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DefKind::Ctor(CtorOf::Variant, _) => "enum constructor".into(),
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_ => "fn item".into(),
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},
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ty::FnPtr(_) => "fn pointer".into(),
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ty::Dynamic(ref inner, ..) if let Some(principal) = inner.principal() => {
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format!("`dyn {}`", tcx.def_path_str(principal.def_id())).into()
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}
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ty::Dynamic(..) => "trait object".into(),
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ty::Closure(..) => "closure".into(),
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ty::Generator(def_id, ..) => tcx.generator_kind(def_id).unwrap().descr().into(),
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ty::GeneratorWitness(..) |
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ty::GeneratorWitnessMIR(..) => "generator witness".into(),
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ty::Infer(ty::TyVar(_)) => "inferred type".into(),
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ty::Infer(ty::IntVar(_)) => "integer".into(),
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ty::Infer(ty::FloatVar(_)) => "floating-point number".into(),
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ty::Placeholder(..) => "placeholder type".into(),
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ty::Bound(..) => "bound type".into(),
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ty::Infer(ty::FreshTy(_)) => "fresh type".into(),
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ty::Infer(ty::FreshIntTy(_)) => "fresh integral type".into(),
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ty::Infer(ty::FreshFloatTy(_)) => "fresh floating-point type".into(),
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ty::Alias(ty::Projection | ty::Inherent, _) => "associated type".into(),
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ty::Param(p) => format!("type parameter `{p}`").into(),
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ty::Alias(ty::Opaque, ..) => if tcx.ty_is_opaque_future(self) { "future".into() } else { "opaque type".into() },
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ty::Error(_) => "type error".into(),
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_ => {
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let width = tcx.sess.diagnostic_width();
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let length_limit = std::cmp::max(width / 4, 15);
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format!("`{}`", tcx.ty_string_with_limit(self, length_limit)).into()
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}
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}
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}
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pub fn prefix_string(self, tcx: TyCtxt<'_>) -> Cow<'static, str> {
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match *self.kind() {
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ty::Infer(_)
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| ty::Error(_)
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| ty::Bool
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| ty::Char
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| ty::Int(_)
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| ty::Uint(_)
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| ty::Float(_)
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| ty::Str
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| ty::Never => "type".into(),
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ty::Tuple(ref tys) if tys.is_empty() => "unit type".into(),
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ty::Adt(def, _) => def.descr().into(),
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ty::Foreign(_) => "extern type".into(),
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ty::Array(..) => "array".into(),
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ty::Slice(_) => "slice".into(),
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ty::RawPtr(_) => "raw pointer".into(),
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ty::Ref(.., mutbl) => match mutbl {
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hir::Mutability::Mut => "mutable reference",
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_ => "reference",
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}
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.into(),
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ty::FnDef(def_id, ..) => match tcx.def_kind(def_id) {
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DefKind::Ctor(CtorOf::Struct, _) => "struct constructor".into(),
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DefKind::Ctor(CtorOf::Variant, _) => "enum constructor".into(),
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_ => "fn item".into(),
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},
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ty::FnPtr(_) => "fn pointer".into(),
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ty::Dynamic(..) => "trait object".into(),
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ty::Closure(..) => "closure".into(),
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ty::Generator(def_id, ..) => tcx.generator_kind(def_id).unwrap().descr().into(),
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ty::GeneratorWitness(..) | ty::GeneratorWitnessMIR(..) => "generator witness".into(),
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ty::Tuple(..) => "tuple".into(),
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ty::Placeholder(..) => "higher-ranked type".into(),
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ty::Bound(..) => "bound type variable".into(),
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ty::Alias(ty::Projection | ty::Inherent, _) => "associated type".into(),
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ty::Alias(ty::Weak, _) => "type alias".into(),
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ty::Param(_) => "type parameter".into(),
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ty::Alias(ty::Opaque, ..) => "opaque type".into(),
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}
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}
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}
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impl<'tcx> TyCtxt<'tcx> {
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pub fn ty_string_with_limit(self, ty: Ty<'tcx>, length_limit: usize) -> String {
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let mut type_limit = 50;
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let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
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.pretty_print_type(ty)
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.expect("could not write to `String`")
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.into_buffer();
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if regular.len() <= length_limit {
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return regular;
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}
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let mut short;
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loop {
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// Look for the longest properly trimmed path that still fits in length_limit.
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short = with_forced_trimmed_paths!(
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FmtPrinter::new_with_limit(
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self,
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hir::def::Namespace::TypeNS,
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rustc_session::Limit(type_limit),
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)
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.pretty_print_type(ty)
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.expect("could not write to `String`")
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.into_buffer()
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);
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if short.len() <= length_limit || type_limit == 0 {
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break;
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}
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type_limit -= 1;
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}
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short
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}
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pub fn short_ty_string(self, ty: Ty<'tcx>) -> (String, Option<PathBuf>) {
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let regular = FmtPrinter::new(self, hir::def::Namespace::TypeNS)
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.pretty_print_type(ty)
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.expect("could not write to `String`")
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.into_buffer();
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if !self.sess.opts.unstable_opts.write_long_types_to_disk {
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return (regular, None);
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}
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let width = self.sess.diagnostic_width();
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let length_limit = width.saturating_sub(30);
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if regular.len() <= width {
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return (regular, None);
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}
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let short = self.ty_string_with_limit(ty, length_limit);
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if regular == short {
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return (regular, None);
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}
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// Multiple types might be shortened in a single error, ensure we create a file for each.
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let mut s = DefaultHasher::new();
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ty.hash(&mut s);
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let hash = s.finish();
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let path = self.output_filenames(()).temp_path_ext(&format!("long-type-{hash}.txt"), None);
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match std::fs::write(&path, ®ular) {
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Ok(_) => (short, Some(path)),
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Err(_) => (regular, None),
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}
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}
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}
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