bjoernager/rust
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Make suggestion to change Fn to FnMut work with methods well

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This commit is contained in:
Gurinder Singh 2024-06-10 16:28:05 +05:30
parent d2fb97fcec
commit e47ea38da8
3 changed files with 126 additions and 44 deletions
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113
compiler/rustc_borrowck/src/diagnostics/mutability_errors.rs
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@ -937,56 +937,81 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
let node = self.infcx.tcx.hir_node(fn_call_id);
let def_id = hir.enclosing_body_owner(fn_call_id);
let mut look_at_return = true;
// If we can detect the expression to be an `fn` call where the closure was an argument,
// we point at the `fn` definition argument...
if let hir::Node::Expr(hir::Expr { kind: hir::ExprKind::Call(func, args), .. }) = node {
let arg_pos = args
// If the HIR node is a function or method call gets the def ID
// of the called function or method and the span and args of the call expr
let get_call_details = || {
let hir::Node::Expr(hir::Expr { hir_id, kind, .. }) = node else {
return None;
};
let typeck_results = self.infcx.tcx.typeck(def_id);
match kind {
hir::ExprKind::Call(expr, args) => {
if let Some(ty::FnDef(def_id, _)) =
typeck_results.node_type_opt(expr.hir_id).as_ref().map(|ty| ty.kind())
{
Some((*def_id, expr.span, *args))
} else {
None
}
}
hir::ExprKind::MethodCall(_, _, args, span) => {
if let Some(def_id) = typeck_results.type_dependent_def_id(*hir_id) {
Some((def_id, *span, *args))
} else {
None
}
}
_ => None,
}
};
// If we can detect the expression to be an function or method call where the closure was an argument,
// we point at the function or method definition argument...
if let Some((callee_def_id, call_span, call_args)) = get_call_details() {
let arg_pos = call_args
.iter()
.enumerate()
.filter(|(_, arg)| arg.hir_id == closure_id)
.map(|(pos, _)| pos)
.next();
let tables = self.infcx.tcx.typeck(def_id);
if let Some(ty::FnDef(def_id, _)) =
tables.node_type_opt(func.hir_id).as_ref().map(|ty| ty.kind())
{
let arg = match hir.get_if_local(*def_id) {
Some(
hir::Node::Item(hir::Item {
ident, kind: hir::ItemKind::Fn(sig, ..), ..
let arg = match hir.get_if_local(callee_def_id) {
Some(
hir::Node::Item(hir::Item { ident, kind: hir::ItemKind::Fn(sig, ..), .. })
| hir::Node::TraitItem(hir::TraitItem {
ident,
kind: hir::TraitItemKind::Fn(sig, _),
..
})
| hir::Node::ImplItem(hir::ImplItem {
ident,
kind: hir::ImplItemKind::Fn(sig, _),
..
}),
) => Some(
arg_pos
.and_then(|pos| {
sig.decl.inputs.get(
pos + if sig.decl.implicit_self.has_implicit_self() {
1
} else {
0
},
)
})
| hir::Node::TraitItem(hir::TraitItem {
ident,
kind: hir::TraitItemKind::Fn(sig, _),
..
})
| hir::Node::ImplItem(hir::ImplItem {
ident,
kind: hir::ImplItemKind::Fn(sig, _),
..
}),
) => Some(
arg_pos
.and_then(|pos| {
sig.decl.inputs.get(
pos + if sig.decl.implicit_self.has_implicit_self() {
1
} else {
0
},
)
})
.map(|arg| arg.span)
.unwrap_or(ident.span),
),
_ => None,
};
if let Some(span) = arg {
err.span_label(span, "change this to accept `FnMut` instead of `Fn`");
err.span_label(func.span, "expects `Fn` instead of `FnMut`");
err.span_label(closure_span, "in this closure");
look_at_return = false;
}
.map(|arg| arg.span)
.unwrap_or(ident.span),
),
_ => None,
};
if let Some(span) = arg {
err.span_label(span, "change this to accept `FnMut` instead of `Fn`");
err.span_label(call_span, "expects `Fn` instead of `FnMut`");
err.span_label(closure_span, "in this closure");
look_at_return = false;
}
}