use rustc_middle::ty::error::TypeError;
// An issue that might be found in the compatibility matrix
+#[derive(Debug)]
enum Issue {
/// The given argument is the invalid type for the input
Invalid(usize),
}
/// Similar to `Issue`, but contains some extra information
+#[derive(Debug)]
pub(crate) enum Error<'tcx> {
- /// The given argument is the invalid type for the input
- Invalid(usize, Compatibility<'tcx>),
+ /// The provided argument is the invalid type for the expected input
+ Invalid(usize, usize, Compatibility<'tcx>), // provided, expected
/// There is a missing input
Missing(usize),
/// There's a superfluous argument
}
pub(crate) struct ArgMatrix<'tcx> {
+ /// Maps the indices in the `compatibility_matrix` rows to the indices of
+ /// the *user provided* inputs
input_indexes: Vec<usize>,
+ /// Maps the indices in the `compatibility_matrix` columns to the indices
+ /// of the *expected* args
arg_indexes: Vec<usize>,
+ /// The first dimension (rows) are the remaining user provided inputs to
+ /// match and the second dimension (cols) are the remaining expected args
+ /// to match
compatibility_matrix: Vec<Vec<Compatibility<'tcx>>>,
}
.map(|i| (0..minimum_input_count).map(|j| is_compatible(i, j)).collect())
.collect();
ArgMatrix {
- input_indexes: (0..minimum_input_count).collect(),
- arg_indexes: (0..provided_arg_count).collect(),
+ input_indexes: (0..provided_arg_count).collect(),
+ arg_indexes: (0..minimum_input_count).collect(),
compatibility_matrix,
}
}
/// Remove a given input from consideration
fn eliminate_input(&mut self, idx: usize) {
self.input_indexes.remove(idx);
- for row in &mut self.compatibility_matrix {
- row.remove(idx);
- }
+ self.compatibility_matrix.remove(idx);
}
/// Remove a given argument from consideration
fn eliminate_arg(&mut self, idx: usize) {
self.arg_indexes.remove(idx);
- self.compatibility_matrix.remove(idx);
+ for row in &mut self.compatibility_matrix {
+ row.remove(idx);
+ }
}
/// "satisfy" an input with a given arg, removing both from consideration
self.eliminate_arg(arg_idx);
}
+ // Returns a `Vec` of (user input, expected arg) of matched arguments. These
+ // are inputs on the remaining diagonal that match.
fn eliminate_satisfied(&mut self) -> Vec<(usize, usize)> {
let mut i = cmp::min(self.input_indexes.len(), self.arg_indexes.len());
let mut eliminated = vec![];
while i > 0 {
let idx = i - 1;
if matches!(self.compatibility_matrix[idx][idx], Compatibility::Compatible) {
- eliminated.push((self.arg_indexes[idx], self.input_indexes[idx]));
+ eliminated.push((self.input_indexes[idx], self.arg_indexes[idx]));
self.satisfy_input(idx, idx);
}
i -= 1;
return eliminated;
}
- // Check for the above mismatch cases
+ // Find some issue in the compatibility matrix
fn find_issue(&self) -> Option<Issue> {
let mat = &self.compatibility_matrix;
let ai = &self.arg_indexes;
if is_arg {
for j in 0..ii.len() {
// If we find at least one input this argument could satisfy
- // this argument isn't completely useless
- if matches!(mat[i][j], Compatibility::Compatible) {
- useless = false;
+ // this argument isn't unsatisfiable
+ if matches!(mat[j][i], Compatibility::Compatible) {
+ unsatisfiable = false;
break;
}
}
if is_input {
for j in 0..ai.len() {
// If we find at least one argument that could satisfy this input
- // this argument isn't unsatisfiable
- if matches!(mat[j][i], Compatibility::Compatible) {
- unsatisfiable = false;
+ // this argument isn't useless
+ if matches!(mat[i][j], Compatibility::Compatible) {
+ useless = false;
break;
}
}
}
- match (is_arg, is_input, useless, unsatisfiable) {
- // If an input is unsatisfied, and the argument in its position is useless
+ match (is_input, is_arg, useless, unsatisfiable) {
+ // If an argument is unsatisfied, and the input in its position is useless
// then the most likely explanation is that we just got the types wrong
(true, true, true, true) => return Some(Issue::Invalid(i)),
// Otherwise, if an input is useless, then indicate that this is an extra argument
_ => {
continue;
}
- };
+ }
}
// We didn't find any of the individual issues above, but
// We'll want to know which arguments and inputs these rows and columns correspond to
// even after we delete them.
pub(crate) fn find_errors(mut self) -> (Vec<Error<'tcx>>, Vec<Option<usize>>) {
- let provided_arg_count = self.arg_indexes.len();
+ let provided_arg_count = self.input_indexes.len();
let mut errors: Vec<Error<'tcx>> = vec![];
// For each expected argument, the matched *actual* input
- let mut matched_inputs: Vec<Option<usize>> = vec![None; self.input_indexes.len()];
+ let mut matched_inputs: Vec<Option<usize>> = vec![None; self.arg_indexes.len()];
// Before we start looking for issues, eliminate any arguments that are already satisfied,
// so that an argument which is already spoken for by the input it's in doesn't
// Without this elimination, the first argument causes the second argument
// to show up as both a missing input and extra argument, rather than
// just an invalid type.
- for (arg, inp) in self.eliminate_satisfied() {
- matched_inputs[inp] = Some(arg);
+ for (inp, arg) in self.eliminate_satisfied() {
+ matched_inputs[arg] = Some(inp);
}
while self.input_indexes.len() > 0 || self.arg_indexes.len() > 0 {
- // Check for the first relevant issue
match self.find_issue() {
Some(Issue::Invalid(idx)) => {
let compatibility = self.compatibility_matrix[idx][idx].clone();
let input_idx = self.input_indexes[idx];
+ let arg_idx = self.arg_indexes[idx];
self.satisfy_input(idx, idx);
- errors.push(Error::Invalid(input_idx, compatibility));
+ errors.push(Error::Invalid(input_idx, arg_idx, compatibility));
}
Some(Issue::Extra(idx)) => {
- let arg_idx = self.arg_indexes[idx];
- self.eliminate_arg(idx);
- errors.push(Error::Extra(arg_idx));
- }
- Some(Issue::Missing(idx)) => {
let input_idx = self.input_indexes[idx];
self.eliminate_input(idx);
- errors.push(Error::Missing(input_idx));
+ errors.push(Error::Extra(input_idx));
+ }
+ Some(Issue::Missing(idx)) => {
+ let arg_idx = self.arg_indexes[idx];
+ self.eliminate_arg(idx);
+ errors.push(Error::Missing(arg_idx));
}
Some(Issue::Swap(idx, other)) => {
let input_idx = self.input_indexes[idx];
// Subtract 1 because we already removed the "min" row
self.satisfy_input(max - 1, min);
errors.push(Error::Swap(input_idx, other_input_idx, arg_idx, other_arg_idx));
- matched_inputs[input_idx] = Some(other_arg_idx);
- matched_inputs[other_input_idx] = Some(arg_idx);
+ matched_inputs[other_arg_idx] = Some(input_idx);
+ matched_inputs[arg_idx] = Some(other_input_idx);
}
Some(Issue::Permutation(args)) => {
- // FIXME: If satisfy_input ever did anything non-trivial (emit obligations to help type checking, for example)
- // we'd want to call this function with the correct arg/input pairs, but for now, we just throw them in a bucket.
- // This works because they force a cycle, so each row is guaranteed to also be a column
let mut idxs: Vec<usize> = args.iter().filter_map(|&a| a).collect();
let mut real_idxs = vec![None; provided_arg_count];
for (src, dst) in
args.iter().enumerate().filter_map(|(src, dst)| dst.map(|dst| (src, dst)))
{
- let src_arg = self.arg_indexes[src];
- let dst_arg = self.arg_indexes[dst];
- let dest_input = self.input_indexes[dst];
- real_idxs[src_arg] = Some((dst_arg, dest_input));
- matched_inputs[dest_input] = Some(src_arg);
+ let src_input_idx = self.input_indexes[src];
+ let dst_input_idx = self.input_indexes[dst];
+ let dest_arg_idx = self.arg_indexes[dst];
+ real_idxs[src_input_idx] = Some((dest_arg_idx, dst_input_idx));
+ matched_inputs[dest_arg_idx] = Some(src_input_idx);
}
idxs.sort();
idxs.reverse();
None => {
// We didn't find any issues, so we need to push the algorithm forward
// First, eliminate any arguments that currently satisfy their inputs
- for (arg, inp) in self.eliminate_satisfied() {
- matched_inputs[inp] = Some(arg);
+ for (inp, arg) in self.eliminate_satisfied() {
+ matched_inputs[arg] = Some(inp);
}
}
};
// A "softer" version of the helper above, which checks types without persisting them,
// and treats error types differently
// This will allow us to "probe" for other argument orders that would likely have been correct
- let check_compatible = |arg_idx, input_idx| {
- let formal_input_ty: Ty<'tcx> = formal_input_tys[input_idx];
- let expected_input_ty: Ty<'tcx> = expected_input_tys[input_idx];
+ let check_compatible = |input_idx, arg_idx| {
+ let formal_input_ty: Ty<'tcx> = formal_input_tys[arg_idx];
+ let expected_input_ty: Ty<'tcx> = expected_input_tys[arg_idx];
// If either is an error type, we defy the usual convention and consider them to *not* be
// coercible. This prevents our error message heuristic from trying to pass errors into
return Compatibility::Incompatible(None);
}
- let provided_arg: &hir::Expr<'tcx> = &provided_args[arg_idx];
+ let provided_arg: &hir::Expr<'tcx> = &provided_args[input_idx];
let expectation = Expectation::rvalue_hint(self, expected_input_ty);
// FIXME: check that this is safe; I don't believe this commits any of the obligations, but I can't be sure.
//
let found_errors = !errors.is_empty();
errors.drain_filter(|error| {
- let Error::Invalid(input_idx, Compatibility::Incompatible(error)) = error else { return false };
- let expected_ty = expected_input_tys[*input_idx];
- let Some(Some((provided_ty, _))) = final_arg_types.get(*input_idx) else { return false };
+ let Error::Invalid(input_idx, arg_idx, Compatibility::Incompatible(error)) = error else { return false };
+ let expected_ty = expected_input_tys[*arg_idx];
+ let provided_ty = final_arg_types[*input_idx].map(|ty| ty.0).unwrap();
let cause = &self.misc(provided_args[*input_idx].span);
- let trace = TypeTrace::types(cause, true, expected_ty, *provided_ty);
+ let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
if let Some(e) = error {
if !matches!(trace.cause.as_failure_code(e), FailureCode::Error0308(_)) {
self.report_and_explain_type_error(trace, e).emit();
// Next special case: if there is only one "Incompatible" error, just emit that
if errors.len() == 1 {
- if let Some(Error::Invalid(input_idx, Compatibility::Incompatible(Some(error)))) =
- errors.iter().next()
+ if let Some(Error::Invalid(
+ input_idx,
+ arg_idx,
+ Compatibility::Incompatible(Some(error)),
+ )) = errors.iter().next()
{
- let expected_ty = expected_input_tys[*input_idx];
- let provided_ty = final_arg_types[*input_idx].map(|ty| ty.0).unwrap();
+ let expected_ty = expected_input_tys[*arg_idx];
+ let provided_ty = final_arg_types[*arg_idx].map(|ty| ty.0).unwrap();
let expected_ty = self.resolve_vars_if_possible(expected_ty);
let provided_ty = self.resolve_vars_if_possible(provided_ty);
let cause = &self.misc(provided_args[*input_idx].span);
let mut errors = errors.into_iter().peekable();
while let Some(error) = errors.next() {
match error {
- Error::Invalid(input_idx, compatibility) => {
- let expected_ty = expected_input_tys[input_idx];
- let provided_ty = final_arg_types
- .get(input_idx)
- .and_then(|x| x.as_ref())
- .map(|ty| ty.0)
- .unwrap_or(tcx.ty_error());
+ Error::Invalid(input_idx, arg_idx, compatibility) => {
+ let expected_ty = expected_input_tys[arg_idx];
+ let provided_ty = final_arg_types[input_idx].map(|ty| ty.0).unwrap();
let expected_ty = self.resolve_vars_if_possible(expected_ty);
let provided_ty = self.resolve_vars_if_possible(provided_ty);
if let Compatibility::Incompatible(error) = &compatibility {
- let cause = &self.misc(
- provided_args.get(input_idx).map(|i| i.span).unwrap_or(call_span),
- );
+ let cause = &self.misc(provided_args[input_idx].span);
let trace = TypeTrace::types(cause, true, expected_ty, provided_ty);
if let Some(e) = error {
self.note_type_err(
}
}
- if let Some(expr) = provided_args.get(input_idx) {
- self.emit_coerce_suggestions(
- &mut err,
- &expr,
- final_arg_types[input_idx].map(|ty| ty.0).unwrap(),
- final_arg_types[input_idx].map(|ty| ty.1).unwrap(),
- None,
- None,
- );
- }
+ self.emit_coerce_suggestions(
+ &mut err,
+ &provided_args[input_idx],
+ final_arg_types[input_idx].map(|ty| ty.0).unwrap(),
+ final_arg_types[input_idx].map(|ty| ty.1).unwrap(),
+ None,
+ None,
+ );
}
Error::Extra(arg_idx) => {
let arg_type = if let Some((_, ty)) = final_arg_types[arg_idx] {
}
}
Error::Swap(input_idx, other_input_idx, arg_idx, other_arg_idx) => {
- let first_span = provided_args[arg_idx].span;
- let second_span = provided_args[other_arg_idx].span;
+ let first_span = provided_args[input_idx].span;
+ let second_span = provided_args[other_input_idx].span;
let first_expected_ty =
- self.resolve_vars_if_possible(expected_input_tys[input_idx]);
- let first_provided_ty = if let Some((ty, _)) = final_arg_types[arg_idx] {
+ self.resolve_vars_if_possible(expected_input_tys[arg_idx]);
+ let first_provided_ty = if let Some((ty, _)) = final_arg_types[input_idx] {
format!(",found `{}`", ty)
} else {
"".into()
format!("expected `{}`{}", first_expected_ty, first_provided_ty),
));
let other_expected_ty =
- self.resolve_vars_if_possible(expected_input_tys[other_input_idx]);
+ self.resolve_vars_if_possible(expected_input_tys[other_arg_idx]);
let other_provided_ty =
- if let Some((ty, _)) = final_arg_types[other_arg_idx] {
+ if let Some((ty, _)) = final_arg_types[other_input_idx] {
format!(",found `{}`", ty)
} else {
"".into()
"{}(",
source_map.span_to_snippet(full_call_span).unwrap_or_else(|_| String::new())
);
- for (idx, arg) in matched_inputs.iter().enumerate() {
- let suggestion_text = if let Some(arg) = arg {
- let arg_span = provided_args[*arg].span.source_callsite();
+ for (arg_index, input_idx) in matched_inputs.iter().enumerate() {
+ let suggestion_text = if let Some(input_idx) = input_idx {
+ let arg_span = provided_args[*input_idx].span.source_callsite();
let arg_text = source_map.span_to_snippet(arg_span).unwrap();
arg_text
} else {
// Propose a placeholder of the correct type
- let expected_ty = expected_input_tys[idx];
+ let expected_ty = expected_input_tys[arg_index];
let input_ty = self.resolve_vars_if_possible(expected_ty);
if input_ty.is_unit() {
"()".to_string()
}
};
suggestion += &suggestion_text;
- if idx < minimum_input_count - 1 {
+ if arg_index < minimum_input_count - 1 {
suggestion += ", ";
}
}
projects / rust.git / commitdiff