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typeck/expr.rs: move check_field + struct helpers here.

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This commit is contained in:
Mazdak Farrokhzad 2019-06-15 03:32:16 +02:00
parent 5ee36b7eca
commit 5057552dc6
2 changed files with 412 additions and 408 deletions
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411
src/librustc_typeck/check/expr.rs
View file

@ -15,12 +15,15 @@ use crate::check::TupleArgumentsFlag::DontTupleArguments;
use crate::check::method::SelfSource;
use crate::middle::lang_items;
use crate::util::common::ErrorReported;
use crate::util::nodemap::FxHashMap;
use crate::astconv::AstConv as _;
use errors::Applicability;
use errors::{Applicability, DiagnosticBuilder};
use syntax::ast;
use syntax::ptr::P;
use syntax::symbol::{kw, sym};
use syntax::symbol::{Symbol, LocalInternedString, kw, sym};
use syntax::source_map::Span;
use syntax::util::lev_distance::find_best_match_for_name;
use rustc::hir;
use rustc::hir::{ExprKind, QPath};
use rustc::hir::def::{CtorKind, Res, DefKind};
@ -31,11 +34,14 @@ use rustc::ty;
use rustc::ty::adjustment::{
Adjust, Adjustment, AllowTwoPhase, AutoBorrow, AutoBorrowMutability,
};
use rustc::ty::{AdtKind, Visibility};
use rustc::ty::Ty;
use rustc::ty::TypeFoldable;
use rustc::ty::subst::InternalSubsts;
use rustc::traits::{self, ObligationCauseCode};
use std::fmt::Display;
impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
fn check_expr_eq_type(&self, expr: &'tcx hir::Expr, expected: Ty<'tcx>) {
let ty = self.check_expr_with_hint(expr, expected);
@ -1057,6 +1063,407 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
adt_ty
}
fn check_expr_struct_fields(
&self,
adt_ty: Ty<'tcx>,
expected: Expectation<'tcx>,
expr_id: hir::HirId,
span: Span,
variant: &'tcx ty::VariantDef,
ast_fields: &'tcx [hir::Field],
check_completeness: bool,
) -> bool {
let tcx = self.tcx;
let adt_ty_hint =
self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty])
.get(0).cloned().unwrap_or(adt_ty);
// re-link the regions that EIfEO can erase.
self.demand_eqtype(span, adt_ty_hint, adt_ty);
let (substs, adt_kind, kind_name) = match &adt_ty.sty {
&ty::Adt(adt, substs) => {
(substs, adt.adt_kind(), adt.variant_descr())
}
_ => span_bug!(span, "non-ADT passed to check_expr_struct_fields")
};
let mut remaining_fields = variant.fields.iter().enumerate().map(|(i, field)|
(field.ident.modern(), (i, field))
).collect::<FxHashMap<_, _>>();
let mut seen_fields = FxHashMap::default();
let mut error_happened = false;
// Type-check each field.
for field in ast_fields {
let ident = tcx.adjust_ident(field.ident, variant.def_id);
let field_type = if let Some((i, v_field)) = remaining_fields.remove(&ident) {
seen_fields.insert(ident, field.span);
self.write_field_index(field.hir_id, i);
// We don't look at stability attributes on
// struct-like enums (yet...), but it's definitely not
// a bug to have constructed one.
if adt_kind != AdtKind::Enum {
tcx.check_stability(v_field.did, Some(expr_id), field.span);
}
self.field_ty(field.span, v_field, substs)
} else {
error_happened = true;
if let Some(prev_span) = seen_fields.get(&ident) {
let mut err = struct_span_err!(self.tcx.sess,
field.ident.span,
E0062,
"field `{}` specified more than once",
ident);
err.span_label(field.ident.span, "used more than once");
err.span_label(*prev_span, format!("first use of `{}`", ident));
err.emit();
} else {
self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name);
}
tcx.types.err
};
// Make sure to give a type to the field even if there's
// an error, so we can continue type-checking.
self.check_expr_coercable_to_type(&field.expr, field_type);
}
// Make sure the programmer specified correct number of fields.
if kind_name == "union" {
if ast_fields.len() != 1 {
tcx.sess.span_err(span, "union expressions should have exactly one field");
}
} else if check_completeness && !error_happened && !remaining_fields.is_empty() {
let len = remaining_fields.len();
let mut displayable_field_names = remaining_fields
.keys()
.map(|ident| ident.as_str())
.collect::<Vec<_>>();
displayable_field_names.sort();
let truncated_fields_error = if len <= 3 {
String::new()
} else {
format!(" and {} other field{}", (len - 3), if len - 3 == 1 {""} else {"s"})
};
let remaining_fields_names = displayable_field_names.iter().take(3)
.map(|n| format!("`{}`", n))
.collect::<Vec<_>>()
.join(", ");
struct_span_err!(tcx.sess, span, E0063,
"missing field{} {}{} in initializer of `{}`",
if remaining_fields.len() == 1 { "" } else { "s" },
remaining_fields_names,
truncated_fields_error,
adt_ty)
.span_label(span, format!("missing {}{}",
remaining_fields_names,
truncated_fields_error))
.emit();
}
error_happened
}
fn check_struct_fields_on_error(
&self,
fields: &'tcx [hir::Field],
base_expr: &'tcx Option<P<hir::Expr>>,
) {
for field in fields {
self.check_expr(&field.expr);
}
if let Some(ref base) = *base_expr {
self.check_expr(&base);
}
}
fn report_unknown_field(
&self,
ty: Ty<'tcx>,
variant: &'tcx ty::VariantDef,
field: &hir::Field,
skip_fields: &[hir::Field],
kind_name: &str,
) {
if variant.recovered {
return;
}
let mut err = self.type_error_struct_with_diag(
field.ident.span,
|actual| match ty.sty {
ty::Adt(adt, ..) if adt.is_enum() => {
struct_span_err!(self.tcx.sess, field.ident.span, E0559,
"{} `{}::{}` has no field named `{}`",
kind_name, actual, variant.ident, field.ident)
}
_ => {
struct_span_err!(self.tcx.sess, field.ident.span, E0560,
"{} `{}` has no field named `{}`",
kind_name, actual, field.ident)
}
},
ty);
// prevent all specified fields from being suggested
let skip_fields = skip_fields.iter().map(|ref x| x.ident.as_str());
if let Some(field_name) = Self::suggest_field_name(variant,
&field.ident.as_str(),
skip_fields.collect()) {
err.span_suggestion(
field.ident.span,
"a field with a similar name exists",
field_name.to_string(),
Applicability::MaybeIncorrect,
);
} else {
match ty.sty {
ty::Adt(adt, ..) => {
if adt.is_enum() {
err.span_label(field.ident.span,
format!("`{}::{}` does not have this field",
ty, variant.ident));
} else {
err.span_label(field.ident.span,
format!("`{}` does not have this field", ty));
}
let available_field_names = self.available_field_names(variant);
if !available_field_names.is_empty() {
err.note(&format!("available fields are: {}",
self.name_series_display(available_field_names)));
}
}
_ => bug!("non-ADT passed to report_unknown_field")
}
};
err.emit();
}
// Return an hint about the closest match in field names
fn suggest_field_name(variant: &'tcx ty::VariantDef,
field: &str,
skip: Vec<LocalInternedString>)
-> Option<Symbol> {
let names = variant.fields.iter().filter_map(|field| {
// ignore already set fields and private fields from non-local crates
if skip.iter().any(|x| *x == field.ident.as_str()) ||
(!variant.def_id.is_local() && field.vis != Visibility::Public)
{
None
} else {
Some(&field.ident.name)
}
});
find_best_match_for_name(names, field, None)
}
fn available_field_names(&self, variant: &'tcx ty::VariantDef) -> Vec<ast::Name> {
variant.fields.iter().filter(|field| {
let def_scope =
self.tcx.adjust_ident_and_get_scope(field.ident, variant.def_id, self.body_id).1;
field.vis.is_accessible_from(def_scope, self.tcx)
})
.map(|field| field.ident.name)
.collect()
}
fn name_series_display(&self, names: Vec<ast::Name>) -> String {
// dynamic limit, to never omit just one field
let limit = if names.len() == 6 { 6 } else { 5 };
let mut display = names.iter().take(limit)
.map(|n| format!("`{}`", n)).collect::<Vec<_>>().join(", ");
if names.len() > limit {
display = format!("{} ... and {} others", display, names.len() - limit);
}
display
}
// Check field access expressions
fn check_field(
&self,
expr: &'tcx hir::Expr,
needs: Needs,
base: &'tcx hir::Expr,
field: ast::Ident,
) -> Ty<'tcx> {
let expr_t = self.check_expr_with_needs(base, needs);
let expr_t = self.structurally_resolved_type(base.span,
expr_t);
let mut private_candidate = None;
let mut autoderef = self.autoderef(expr.span, expr_t);
while let Some((base_t, _)) = autoderef.next() {
match base_t.sty {
ty::Adt(base_def, substs) if !base_def.is_enum() => {
debug!("struct named {:?}", base_t);
let (ident, def_scope) =
self.tcx.adjust_ident_and_get_scope(field, base_def.did, self.body_id);
let fields = &base_def.non_enum_variant().fields;
if let Some(index) = fields.iter().position(|f| f.ident.modern() == ident) {
let field = &fields[index];
let field_ty = self.field_ty(expr.span, field, substs);
// Save the index of all fields regardless of their visibility in case
// of error recovery.
self.write_field_index(expr.hir_id, index);
if field.vis.is_accessible_from(def_scope, self.tcx) {
let adjustments = autoderef.adjust_steps(self, needs);
self.apply_adjustments(base, adjustments);
autoderef.finalize(self);
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span);
return field_ty;
}
private_candidate = Some((base_def.did, field_ty));
}
}
ty::Tuple(ref tys) => {
let fstr = field.as_str();
if let Ok(index) = fstr.parse::<usize>() {
if fstr == index.to_string() {
if let Some(field_ty) = tys.get(index) {
let adjustments = autoderef.adjust_steps(self, needs);
self.apply_adjustments(base, adjustments);
autoderef.finalize(self);
self.write_field_index(expr.hir_id, index);
return field_ty.expect_ty();
}
}
}
}
_ => {}
}
}
autoderef.unambiguous_final_ty(self);
if let Some((did, field_ty)) = private_candidate {
let struct_path = self.tcx().def_path_str(did);
let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
"field `{}` of struct `{}` is private",
field, struct_path);
// Also check if an accessible method exists, which is often what is meant.
if self.method_exists(field, expr_t, expr.hir_id, false)
&& !self.expr_in_place(expr.hir_id)
{
self.suggest_method_call(
&mut err,
&format!("a method `{}` also exists, call it with parentheses", field),
field,
expr_t,
expr.hir_id,
);
}
err.emit();
field_ty
} else if field.name == kw::Invalid {
self.tcx().types.err
} else if self.method_exists(field, expr_t, expr.hir_id, true) {
let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
"attempted to take value of method `{}` on type `{}`",
field, expr_t);
if !self.expr_in_place(expr.hir_id) {
self.suggest_method_call(
&mut err,
"use parentheses to call the method",
field,
expr_t,
expr.hir_id
);
} else {
err.help("methods are immutable and cannot be assigned to");
}
err.emit();
self.tcx().types.err
} else {
if !expr_t.is_primitive_ty() {
let mut err = self.no_such_field_err(field.span, field, expr_t);
match expr_t.sty {
ty::Adt(def, _) if !def.is_enum() => {
if let Some(suggested_field_name) =
Self::suggest_field_name(def.non_enum_variant(),
&field.as_str(), vec![]) {
err.span_suggestion(
field.span,
"a field with a similar name exists",
suggested_field_name.to_string(),
Applicability::MaybeIncorrect,
);
} else {
err.span_label(field.span, "unknown field");
let struct_variant_def = def.non_enum_variant();
let field_names = self.available_field_names(struct_variant_def);
if !field_names.is_empty() {
err.note(&format!("available fields are: {}",
self.name_series_display(field_names)));
}
};
}
ty::Array(_, len) => {
if let (Some(len), Ok(user_index)) = (
len.assert_usize(self.tcx),
field.as_str().parse::<u64>()
) {
let base = self.tcx.sess.source_map()
.span_to_snippet(base.span)
.unwrap_or_else(|_|
self.tcx.hir().hir_to_pretty_string(base.hir_id));
let help = "instead of using tuple indexing, use array indexing";
let suggestion = format!("{}[{}]", base, field);
let applicability = if len < user_index {
Applicability::MachineApplicable
} else {
Applicability::MaybeIncorrect
};
err.span_suggestion(
expr.span, help, suggestion, applicability
);
}
}
ty::RawPtr(..) => {
let base = self.tcx.sess.source_map()
.span_to_snippet(base.span)
.unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
let suggestion = format!("(*{}).{}", base, field);
err.span_suggestion(
expr.span,
&msg,
suggestion,
Applicability::MaybeIncorrect,
);
}
_ => {}
}
err
} else {
type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
"`{}` is a primitive type and therefore doesn't have fields",
expr_t)
}.emit();
self.tcx().types.err
}
}
fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
-> DiagnosticBuilder<'_> {
type_error_struct!(self.tcx().sess, span, expr_t, E0609,
"no field `{}` on type `{}`",
field, expr_t)
}
fn check_expr_index(
&self,
base: &'tcx hir::Expr,

409
src/librustc_typeck/check/mod.rs
View file

@ -106,7 +106,7 @@ use rustc::middle::region;
use rustc::mir::interpret::{ConstValue, GlobalId};
use rustc::traits::{self, ObligationCause, ObligationCauseCode, TraitEngine};
use rustc::ty::{
self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind, Visibility,
self, AdtKind, CanonicalUserType, Ty, TyCtxt, Const, GenericParamDefKind,
ToPolyTraitRef, ToPredicate, RegionKind, UserType
};
use rustc::ty::adjustment::{
@ -124,13 +124,11 @@ use syntax::attr;
use syntax::feature_gate::{GateIssue, emit_feature_err};
use syntax::ptr::P;
use syntax::source_map::{DUMMY_SP, original_sp};
use syntax::symbol::{Symbol, LocalInternedString, kw, sym};
use syntax::util::lev_distance::find_best_match_for_name;
use syntax::symbol::{kw, sym};
use std::cell::{Cell, RefCell, Ref, RefMut};
use std::collections::hash_map::Entry;
use std::cmp;
use std::fmt::Display;
use std::iter;
use std::mem::replace;
use std::ops::{self, Deref};
@ -143,7 +141,7 @@ use crate::TypeAndSubsts;
use crate::lint;
use crate::util::captures::Captures;
use crate::util::common::{ErrorReported, indenter};
use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashMap, FxHashSet, HirIdMap};
use crate::util::nodemap::{DefIdMap, DefIdSet, FxHashSet, HirIdMap};
pub use self::Expectation::*;
use self::autoderef::Autoderef;
@ -3266,407 +3264,6 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
expect_args
}
// Check field access expressions
fn check_field(
&self,
expr: &'tcx hir::Expr,
needs: Needs,
base: &'tcx hir::Expr,
field: ast::Ident,
) -> Ty<'tcx> {
let expr_t = self.check_expr_with_needs(base, needs);
let expr_t = self.structurally_resolved_type(base.span,
expr_t);
let mut private_candidate = None;
let mut autoderef = self.autoderef(expr.span, expr_t);
while let Some((base_t, _)) = autoderef.next() {
match base_t.sty {
ty::Adt(base_def, substs) if !base_def.is_enum() => {
debug!("struct named {:?}", base_t);
let (ident, def_scope) =
self.tcx.adjust_ident_and_get_scope(field, base_def.did, self.body_id);
let fields = &base_def.non_enum_variant().fields;
if let Some(index) = fields.iter().position(|f| f.ident.modern() == ident) {
let field = &fields[index];
let field_ty = self.field_ty(expr.span, field, substs);
// Save the index of all fields regardless of their visibility in case
// of error recovery.
self.write_field_index(expr.hir_id, index);
if field.vis.is_accessible_from(def_scope, self.tcx) {
let adjustments = autoderef.adjust_steps(self, needs);
self.apply_adjustments(base, adjustments);
autoderef.finalize(self);
self.tcx.check_stability(field.did, Some(expr.hir_id), expr.span);
return field_ty;
}
private_candidate = Some((base_def.did, field_ty));
}
}
ty::Tuple(ref tys) => {
let fstr = field.as_str();
if let Ok(index) = fstr.parse::<usize>() {
if fstr == index.to_string() {
if let Some(field_ty) = tys.get(index) {
let adjustments = autoderef.adjust_steps(self, needs);
self.apply_adjustments(base, adjustments);
autoderef.finalize(self);
self.write_field_index(expr.hir_id, index);
return field_ty.expect_ty();
}
}
}
}
_ => {}
}
}
autoderef.unambiguous_final_ty(self);
if let Some((did, field_ty)) = private_candidate {
let struct_path = self.tcx().def_path_str(did);
let mut err = struct_span_err!(self.tcx().sess, expr.span, E0616,
"field `{}` of struct `{}` is private",
field, struct_path);
// Also check if an accessible method exists, which is often what is meant.
if self.method_exists(field, expr_t, expr.hir_id, false)
&& !self.expr_in_place(expr.hir_id)
{
self.suggest_method_call(
&mut err,
&format!("a method `{}` also exists, call it with parentheses", field),
field,
expr_t,
expr.hir_id,
);
}
err.emit();
field_ty
} else if field.name == kw::Invalid {
self.tcx().types.err
} else if self.method_exists(field, expr_t, expr.hir_id, true) {
let mut err = type_error_struct!(self.tcx().sess, field.span, expr_t, E0615,
"attempted to take value of method `{}` on type `{}`",
field, expr_t);
if !self.expr_in_place(expr.hir_id) {
self.suggest_method_call(
&mut err,
"use parentheses to call the method",
field,
expr_t,
expr.hir_id
);
} else {
err.help("methods are immutable and cannot be assigned to");
}
err.emit();
self.tcx().types.err
} else {
if !expr_t.is_primitive_ty() {
let mut err = self.no_such_field_err(field.span, field, expr_t);
match expr_t.sty {
ty::Adt(def, _) if !def.is_enum() => {
if let Some(suggested_field_name) =
Self::suggest_field_name(def.non_enum_variant(),
&field.as_str(), vec![]) {
err.span_suggestion(
field.span,
"a field with a similar name exists",
suggested_field_name.to_string(),
Applicability::MaybeIncorrect,
);
} else {
err.span_label(field.span, "unknown field");
let struct_variant_def = def.non_enum_variant();
let field_names = self.available_field_names(struct_variant_def);
if !field_names.is_empty() {
err.note(&format!("available fields are: {}",
self.name_series_display(field_names)));
}
};
}
ty::Array(_, len) => {
if let (Some(len), Ok(user_index)) = (
len.assert_usize(self.tcx),
field.as_str().parse::<u64>()
) {
let base = self.tcx.sess.source_map()
.span_to_snippet(base.span)
.unwrap_or_else(|_|
self.tcx.hir().hir_to_pretty_string(base.hir_id));
let help = "instead of using tuple indexing, use array indexing";
let suggestion = format!("{}[{}]", base, field);
let applicability = if len < user_index {
Applicability::MachineApplicable
} else {
Applicability::MaybeIncorrect
};
err.span_suggestion(
expr.span, help, suggestion, applicability
);
}
}
ty::RawPtr(..) => {
let base = self.tcx.sess.source_map()
.span_to_snippet(base.span)
.unwrap_or_else(|_| self.tcx.hir().hir_to_pretty_string(base.hir_id));
let msg = format!("`{}` is a raw pointer; try dereferencing it", base);
let suggestion = format!("(*{}).{}", base, field);
err.span_suggestion(
expr.span,
&msg,
suggestion,
Applicability::MaybeIncorrect,
);
}
_ => {}
}
err
} else {
type_error_struct!(self.tcx().sess, field.span, expr_t, E0610,
"`{}` is a primitive type and therefore doesn't have fields",
expr_t)
}.emit();
self.tcx().types.err
}
}
// Return an hint about the closest match in field names
fn suggest_field_name(variant: &'tcx ty::VariantDef,
field: &str,
skip: Vec<LocalInternedString>)
-> Option<Symbol> {
let names = variant.fields.iter().filter_map(|field| {
// ignore already set fields and private fields from non-local crates
if skip.iter().any(|x| *x == field.ident.as_str()) ||
(!variant.def_id.is_local() && field.vis != Visibility::Public)
{
None
} else {
Some(&field.ident.name)
}
});
find_best_match_for_name(names, field, None)
}
fn available_field_names(&self, variant: &'tcx ty::VariantDef) -> Vec<ast::Name> {
variant.fields.iter().filter(|field| {
let def_scope =
self.tcx.adjust_ident_and_get_scope(field.ident, variant.def_id, self.body_id).1;
field.vis.is_accessible_from(def_scope, self.tcx)
})
.map(|field| field.ident.name)
.collect()
}
fn name_series_display(&self, names: Vec<ast::Name>) -> String {
// dynamic limit, to never omit just one field
let limit = if names.len() == 6 { 6 } else { 5 };
let mut display = names.iter().take(limit)
.map(|n| format!("`{}`", n)).collect::<Vec<_>>().join(", ");
if names.len() > limit {
display = format!("{} ... and {} others", display, names.len() - limit);
}
display
}
fn no_such_field_err<T: Display>(&self, span: Span, field: T, expr_t: &ty::TyS<'_>)
-> DiagnosticBuilder<'_> {
type_error_struct!(self.tcx().sess, span, expr_t, E0609,
"no field `{}` on type `{}`",
field, expr_t)
}
fn report_unknown_field(
&self,
ty: Ty<'tcx>,
variant: &'tcx ty::VariantDef,
field: &hir::Field,
skip_fields: &[hir::Field],
kind_name: &str,
) {
if variant.recovered {
return;
}
let mut err = self.type_error_struct_with_diag(
field.ident.span,
|actual| match ty.sty {
ty::Adt(adt, ..) if adt.is_enum() => {
struct_span_err!(self.tcx.sess, field.ident.span, E0559,
"{} `{}::{}` has no field named `{}`",
kind_name, actual, variant.ident, field.ident)
}
_ => {
struct_span_err!(self.tcx.sess, field.ident.span, E0560,
"{} `{}` has no field named `{}`",
kind_name, actual, field.ident)
}
},
ty);
// prevent all specified fields from being suggested
let skip_fields = skip_fields.iter().map(|ref x| x.ident.as_str());
if let Some(field_name) = Self::suggest_field_name(variant,
&field.ident.as_str(),
skip_fields.collect()) {
err.span_suggestion(
field.ident.span,
"a field with a similar name exists",
field_name.to_string(),
Applicability::MaybeIncorrect,
);
} else {
match ty.sty {
ty::Adt(adt, ..) => {
if adt.is_enum() {
err.span_label(field.ident.span,
format!("`{}::{}` does not have this field",
ty, variant.ident));
} else {
err.span_label(field.ident.span,
format!("`{}` does not have this field", ty));
}
let available_field_names = self.available_field_names(variant);
if !available_field_names.is_empty() {
err.note(&format!("available fields are: {}",
self.name_series_display(available_field_names)));
}
}
_ => bug!("non-ADT passed to report_unknown_field")
}
};
err.emit();
}
fn check_expr_struct_fields(
&self,
adt_ty: Ty<'tcx>,
expected: Expectation<'tcx>,
expr_id: hir::HirId,
span: Span,
variant: &'tcx ty::VariantDef,
ast_fields: &'tcx [hir::Field],
check_completeness: bool,
) -> bool {
let tcx = self.tcx;
let adt_ty_hint =
self.expected_inputs_for_expected_output(span, expected, adt_ty, &[adt_ty])
.get(0).cloned().unwrap_or(adt_ty);
// re-link the regions that EIfEO can erase.
self.demand_eqtype(span, adt_ty_hint, adt_ty);
let (substs, adt_kind, kind_name) = match &adt_ty.sty {
&ty::Adt(adt, substs) => {
(substs, adt.adt_kind(), adt.variant_descr())
}
_ => span_bug!(span, "non-ADT passed to check_expr_struct_fields")
};
let mut remaining_fields = variant.fields.iter().enumerate().map(|(i, field)|
(field.ident.modern(), (i, field))
).collect::<FxHashMap<_, _>>();
let mut seen_fields = FxHashMap::default();
let mut error_happened = false;
// Type-check each field.
for field in ast_fields {
let ident = tcx.adjust_ident(field.ident, variant.def_id);
let field_type = if let Some((i, v_field)) = remaining_fields.remove(&ident) {
seen_fields.insert(ident, field.span);
self.write_field_index(field.hir_id, i);
// We don't look at stability attributes on
// struct-like enums (yet...), but it's definitely not
// a bug to have constructed one.
if adt_kind != AdtKind::Enum {
tcx.check_stability(v_field.did, Some(expr_id), field.span);
}
self.field_ty(field.span, v_field, substs)
} else {
error_happened = true;
if let Some(prev_span) = seen_fields.get(&ident) {
let mut err = struct_span_err!(self.tcx.sess,
field.ident.span,
E0062,
"field `{}` specified more than once",
ident);
err.span_label(field.ident.span, "used more than once");
err.span_label(*prev_span, format!("first use of `{}`", ident));
err.emit();
} else {
self.report_unknown_field(adt_ty, variant, field, ast_fields, kind_name);
}
tcx.types.err
};
// Make sure to give a type to the field even if there's
// an error, so we can continue type-checking.
self.check_expr_coercable_to_type(&field.expr, field_type);
}
// Make sure the programmer specified correct number of fields.
if kind_name == "union" {
if ast_fields.len() != 1 {
tcx.sess.span_err(span, "union expressions should have exactly one field");
}
} else if check_completeness && !error_happened && !remaining_fields.is_empty() {
let len = remaining_fields.len();
let mut displayable_field_names = remaining_fields
.keys()
.map(|ident| ident.as_str())
.collect::<Vec<_>>();
displayable_field_names.sort();
let truncated_fields_error = if len <= 3 {
String::new()
} else {
format!(" and {} other field{}", (len - 3), if len - 3 == 1 {""} else {"s"})
};
let remaining_fields_names = displayable_field_names.iter().take(3)
.map(|n| format!("`{}`", n))
.collect::<Vec<_>>()
.join(", ");
struct_span_err!(tcx.sess, span, E0063,
"missing field{} {}{} in initializer of `{}`",
if remaining_fields.len() == 1 { "" } else { "s" },
remaining_fields_names,
truncated_fields_error,
adt_ty)
.span_label(span, format!("missing {}{}",
remaining_fields_names,
truncated_fields_error))
.emit();
}
error_happened
}
fn check_struct_fields_on_error(
&self,
fields: &'tcx [hir::Field],
base_expr: &'tcx Option<P<hir::Expr>>,
) {
for field in fields {
self.check_expr(&field.expr);
}
if let Some(ref base) = *base_expr {
self.check_expr(&base);
}
}
pub fn check_struct_path(&self,
qpath: &QPath,
hir_id: hir::HirId)