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This commit is contained in:
Esteban Küber 2019-03-28 04:47:09 -07:00
parent a51ca0268d
commit 07857f7406
1 changed files with 44 additions and 39 deletions
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83
src/librustc_typeck/check/demand.rs
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@ -249,6 +249,26 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
None
}
fn is_hir_id_from_struct_pattern_shorthand_field(&self, hir_id: hir::HirId) -> bool {
let parent_id = self.tcx.hir().get_parent_node_by_hir_id(expr.hir_id);
let mut is_struct_pat_shorthand_field = false;
if let Some(parent) = self.tcx.hir().find_by_hir_id(parent_id) {
// Account for fields
if let Node::Expr(hir::Expr {
node: hir::ExprKind::Struct(_, fields, ..), ..
}) = parent {
if let Ok(src) = cm.span_to_snippet(sp) {
for field in fields {
if field.ident.as_str() == src.as_str() && field.is_shorthand {
is_struct_pat_shorthand_field = true;
break;
}
}
}
}
};
}
/// This function is used to determine potential "simple" improvements or users' errors and
/// provide them useful help. For example:
///
@ -277,23 +297,8 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
return None;
}
let parent_id = self.tcx.hir().get_parent_node_by_hir_id(expr.hir_id);
let mut is_struct_pat_shorthand_field = false;
if let Some(parent) = self.tcx.hir().find_by_hir_id(parent_id) {
// Account for fields
if let Node::Expr(hir::Expr {
node: hir::ExprKind::Struct(_, fields, ..), ..
}) = parent {
if let Ok(src) = cm.span_to_snippet(sp) {
for field in fields {
if field.ident.as_str() == src.as_str() && field.is_shorthand {
is_struct_pat_shorthand_field = true;
break;
}
}
}
}
};
let mut is_struct_pat_shorthand_field =
self.is_hir_id_from_struct_pattern_shorthand_field(expr.hir_id);
match (&expected.sty, &checked_ty.sty) {
(&ty::Ref(_, exp, _), &ty::Ref(_, check, _)) => match (&exp.sty, &check.sty) {
@ -333,12 +338,12 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
// bar(&x); // error, expected &mut
// ```
let ref_ty = match mutability {
hir::Mutability::MutMutable => self.tcx.mk_mut_ref(
self.tcx.mk_region(ty::ReStatic),
checked_ty),
hir::Mutability::MutImmutable => self.tcx.mk_imm_ref(
self.tcx.mk_region(ty::ReStatic),
checked_ty),
hir::Mutability::MutMutable => {
self.tcx.mk_mut_ref(self.tcx.mk_region(ty::ReStatic), checked_ty)
}
hir::Mutability::MutImmutable => {
self.tcx.mk_imm_ref(self.tcx.mk_region(ty::ReStatic), checked_ty)
}
};
if self.can_coerce(ref_ty, expected) {
if let Ok(src) = cm.span_to_snippet(sp) {
@ -359,22 +364,22 @@ impl<'a, 'gcx, 'tcx> FnCtxt<'a, 'gcx, 'tcx> {
if let Some(sugg) = self.can_use_as_ref(expr) {
return Some(sugg);
}
return Some(match (mutability, is_struct_pat_shorthand_field) {
(hir::Mutability::MutMutable, false) => {
(sp, "consider mutably borrowing here",
format!("&mut {}", sugg_expr))
}
(hir::Mutability::MutImmutable, false) => {
(sp, "consider borrowing here", format!("&{}", sugg_expr))
}
(hir::Mutability::MutMutable, true) => {
(sp, "consider mutably borrowing here",
format!("{}: &mut {}", sugg_expr, sugg_expr))
}
(hir::Mutability::MutImmutable, true) => {
(sp, "consider borrowing here",
format!("{}: &{}", sugg_expr, sugg_expr))
}
let field_name = if is_struct_pat_shorthand_field {
format!("{}: ", sugg_expr)
} else {
String::new()
};
return Some(match mutability {
hir::Mutability::MutMutable => (
sp,
"consider mutably borrowing here",
format!("{}&mut {}", field_name, sugg_expr),
),
hir::Mutability::MutImmutable => (
sp,
"consider borrowing here",
format!("{}&{}", field_name, sugg_expr),
),
});
}
}