modified lint to work with MIR
Working with MIR let's us exclude expressions like `&fn_name as &dyn Something` and `(&fn_name)()`. Also added ABI, unsafety and whether a function is variadic in the lint suggestion, included the `&` in the span of the lint and updated the test.
This commit is contained in:
parent
975547d475
commit
3214de7359
7 changed files with 322 additions and 59 deletions
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@ -2942,37 +2942,3 @@ impl<'tcx> LateLintPass<'tcx> for ClashingExternDeclarations {
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}
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}
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}
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}
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}
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}
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declare_lint! {
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FUNCTION_REFERENCES,
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Warn,
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"suggest casting functions to pointers when attempting to take references"
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}
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declare_lint_pass!(FunctionReferences => [FUNCTION_REFERENCES]);
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impl<'tcx> LateLintPass<'tcx> for FunctionReferences {
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fn check_expr(&mut self, cx: &LateContext<'_>, e: &hir::Expr<'_>) {
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if let hir::ExprKind::AddrOf(hir::BorrowKind::Ref, _, referent) = e.kind {
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if let hir::ExprKind::Path(qpath) = &referent.kind {
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if let Some(def_id) = cx.qpath_res(qpath, referent.hir_id).opt_def_id() {
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cx.tcx.hir().get_if_local(def_id).map(|node| {
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node.fn_decl().map(|decl| {
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if let Some(ident) = node.ident() {
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cx.struct_span_lint(FUNCTION_REFERENCES, referent.span, |lint| {
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let num_args = decl.inputs.len();
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lint.build(&format!(
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"cast `{}` with `as *const fn({}) -> _` to use it as a pointer",
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ident.to_string(),
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vec!["_"; num_args].join(", ")
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))
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.emit()
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});
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}
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});
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});
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}
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}
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}
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}
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}
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@ -194,7 +194,6 @@ macro_rules! late_lint_mod_passes {
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UnreachablePub: UnreachablePub,
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UnreachablePub: UnreachablePub,
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ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
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ExplicitOutlivesRequirements: ExplicitOutlivesRequirements,
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InvalidValue: InvalidValue,
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InvalidValue: InvalidValue,
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FunctionReferences: FunctionReferences,
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]
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]
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);
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);
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};
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};
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158
compiler/rustc_mir/src/transform/function_references.rs
Normal file
158
compiler/rustc_mir/src/transform/function_references.rs
Normal file
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@ -0,0 +1,158 @@
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use rustc_hir::def_id::DefId;
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use rustc_middle::mir::visit::Visitor;
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use rustc_middle::mir::*;
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use rustc_middle::ty::{self, Ty, TyCtxt};
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use rustc_session::lint::builtin::FUNCTION_REFERENCES;
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use rustc_span::Span;
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use rustc_target::spec::abi::Abi;
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use crate::transform::{MirPass, MirSource};
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pub struct FunctionReferences;
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impl<'tcx> MirPass<'tcx> for FunctionReferences {
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fn run_pass(&self, tcx: TyCtxt<'tcx>, _src: MirSource<'tcx>, body: &mut Body<'tcx>) {
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let source_info = SourceInfo::outermost(body.span);
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let mut checker = FunctionRefChecker {
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tcx,
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body,
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potential_lints: Vec::new(),
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casts: Vec::new(),
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calls: Vec::new(),
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source_info,
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};
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checker.visit_body(&body);
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}
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}
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struct FunctionRefChecker<'a, 'tcx> {
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tcx: TyCtxt<'tcx>,
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body: &'a Body<'tcx>,
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potential_lints: Vec<FunctionRefLint>,
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casts: Vec<Span>,
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calls: Vec<Span>,
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source_info: SourceInfo,
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}
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impl<'a, 'tcx> Visitor<'tcx> for FunctionRefChecker<'a, 'tcx> {
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fn visit_basic_block_data(&mut self, block: BasicBlock, data: &BasicBlockData<'tcx>) {
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self.super_basic_block_data(block, data);
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for cast_span in self.casts.drain(..) {
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self.potential_lints.retain(|lint| lint.source_info.span != cast_span);
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}
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for call_span in self.calls.drain(..) {
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self.potential_lints.retain(|lint| lint.source_info.span != call_span);
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}
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for lint in self.potential_lints.drain(..) {
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lint.emit(self.tcx, self.body);
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}
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}
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fn visit_statement(&mut self, statement: &Statement<'tcx>, location: Location) {
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self.source_info = statement.source_info;
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self.super_statement(statement, location);
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}
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fn visit_terminator(&mut self, terminator: &Terminator<'tcx>, location: Location) {
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self.source_info = terminator.source_info;
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if let TerminatorKind::Call {
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func,
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args: _,
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destination: _,
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cleanup: _,
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from_hir_call: _,
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fn_span: _,
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} = &terminator.kind
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{
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let span = match func {
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Operand::Copy(place) | Operand::Move(place) => {
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self.body.local_decls[place.local].source_info.span
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}
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Operand::Constant(constant) => constant.span,
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};
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self.calls.push(span);
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};
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self.super_terminator(terminator, location);
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}
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fn visit_rvalue(&mut self, rvalue: &Rvalue<'tcx>, location: Location) {
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match rvalue {
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Rvalue::Ref(_, _, place) | Rvalue::AddressOf(_, place) => {
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let decl = &self.body.local_decls[place.local];
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if let ty::FnDef(def_id, _) = decl.ty.kind {
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let ident = self
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.body
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.var_debug_info
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.iter()
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.find(|info| info.source_info.span == decl.source_info.span)
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.map(|info| info.name.to_ident_string())
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.unwrap_or(self.tcx.def_path_str(def_id));
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let lint = FunctionRefLint { ident, def_id, source_info: self.source_info };
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self.potential_lints.push(lint);
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}
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}
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Rvalue::Cast(_, op, _) => {
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let op_ty = op.ty(self.body, self.tcx);
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if self.is_fn_ref(op_ty) {
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self.casts.push(self.source_info.span);
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}
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}
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_ => {}
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}
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self.super_rvalue(rvalue, location);
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}
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}
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impl<'a, 'tcx> FunctionRefChecker<'a, 'tcx> {
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fn is_fn_ref(&self, ty: Ty<'tcx>) -> bool {
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let referent_ty = match ty.kind {
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ty::Ref(_, referent_ty, _) => Some(referent_ty),
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ty::RawPtr(ty_and_mut) => Some(ty_and_mut.ty),
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_ => None,
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};
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referent_ty
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.map(|ref_ty| if let ty::FnDef(..) = ref_ty.kind { true } else { false })
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.unwrap_or(false)
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}
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}
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struct FunctionRefLint {
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ident: String,
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def_id: DefId,
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source_info: SourceInfo,
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}
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impl<'tcx> FunctionRefLint {
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fn emit(&self, tcx: TyCtxt<'tcx>, body: &Body<'tcx>) {
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let def_id = self.def_id;
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let source_info = self.source_info;
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let lint_root = body.source_scopes[source_info.scope]
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.local_data
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.as_ref()
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.assert_crate_local()
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.lint_root;
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let fn_sig = tcx.fn_sig(def_id);
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let unsafety = fn_sig.unsafety().prefix_str();
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let abi = match fn_sig.abi() {
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Abi::Rust => String::from(""),
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other_abi => {
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let mut s = String::from("extern \"");
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s.push_str(other_abi.name());
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s.push_str("\" ");
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s
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}
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};
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let num_args = fn_sig.inputs().map_bound(|inputs| inputs.len()).skip_binder();
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let variadic = if fn_sig.c_variadic() { ", ..." } else { "" };
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let ret = if fn_sig.output().skip_binder().is_unit() { "" } else { " -> _" };
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tcx.struct_span_lint_hir(FUNCTION_REFERENCES, lint_root, source_info.span, |lint| {
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lint.build(&format!(
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"cast `{}` with `as {}{}fn({}{}){}` to use it as a pointer",
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self.ident,
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unsafety,
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abi,
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vec!["_"; num_args].join(", "),
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variadic,
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ret,
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))
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.emit()
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});
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}
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}
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@ -27,6 +27,7 @@ pub mod dest_prop;
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pub mod dump_mir;
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pub mod dump_mir;
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pub mod early_otherwise_branch;
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pub mod early_otherwise_branch;
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pub mod elaborate_drops;
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pub mod elaborate_drops;
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pub mod function_references;
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pub mod generator;
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pub mod generator;
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pub mod inline;
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pub mod inline;
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pub mod instcombine;
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pub mod instcombine;
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@ -266,6 +267,7 @@ fn mir_const<'tcx>(
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// MIR-level lints.
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// MIR-level lints.
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&check_packed_ref::CheckPackedRef,
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&check_packed_ref::CheckPackedRef,
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&check_const_item_mutation::CheckConstItemMutation,
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&check_const_item_mutation::CheckConstItemMutation,
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&function_references::FunctionReferences,
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// What we need to do constant evaluation.
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// What we need to do constant evaluation.
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&simplify::SimplifyCfg::new("initial"),
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&simplify::SimplifyCfg::new("initial"),
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&rustc_peek::SanityCheck,
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&rustc_peek::SanityCheck,
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@ -2645,6 +2645,11 @@ declare_lint! {
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reference: "issue #76200 <https://github.com/rust-lang/rust/issues/76200>",
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reference: "issue #76200 <https://github.com/rust-lang/rust/issues/76200>",
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edition: None,
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edition: None,
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};
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};
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declare_lint! {
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pub FUNCTION_REFERENCES,
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Warn,
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"suggest casting functions to pointers when attempting to take references",
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}
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}
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declare_lint! {
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declare_lint! {
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@ -2762,6 +2767,7 @@ declare_lint_pass! {
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CONST_EVALUATABLE_UNCHECKED,
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CONST_EVALUATABLE_UNCHECKED,
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INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
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INEFFECTIVE_UNSTABLE_TRAIT_IMPL,
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UNINHABITED_STATIC,
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UNINHABITED_STATIC,
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FUNCTION_REFERENCES,
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]
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]
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}
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}
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@ -1,22 +1,71 @@
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// check-pass
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// check-pass
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fn foo() -> usize { 42 }
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#![feature(c_variadic)]
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fn bar(x: usize) -> usize { x }
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#![allow(dead_code)]
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fn baz(x: usize, y: usize) -> usize { x + y }
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fn foo() -> u32 { 42 }
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fn bar(x: u32) -> u32 { x }
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fn baz(x: u32, y: u32) -> u32 { x + y }
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unsafe fn unsafe_fn() { }
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extern "C" fn c_fn() { }
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unsafe extern "C" fn unsafe_c_fn() { }
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unsafe extern fn variadic_fn(_x: u32, _args: ...) { }
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fn call_fn(f: &dyn Fn(u32) -> u32, x: u32) { f(x); }
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fn parameterized_call_fn<F: Fn(u32) -> u32>(f: &F, x: u32) { f(x); }
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fn main() {
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fn main() {
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let _zst_ref = &foo;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let fn_item = foo;
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let _indirect_ref = &fn_item;
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//~^ WARN cast `fn_item` with `as fn() -> _` to use it as a pointer
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let _cast_zst_ptr = &foo as *const _;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let _coerced_zst_ptr: *const _ = &foo;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let _zst_ref = &mut foo;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let mut mut_fn_item = foo;
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let _indirect_ref = &mut mut_fn_item;
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//~^ WARN cast `fn_item` with `as fn() -> _` to use it as a pointer
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let _cast_zst_ptr = &mut foo as *mut _;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let _coerced_zst_ptr: *mut _ = &mut foo;
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//~^ WARN cast `foo` with `as fn() -> _` to use it as a pointer
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let _cast_zst_ref = &foo as &dyn Fn() -> u32;
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let _coerced_zst_ref: &dyn Fn() -> u32 = &foo;
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let _cast_zst_ref = &mut foo as &mut dyn Fn() -> u32;
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let _coerced_zst_ref: &mut dyn Fn() -> u32 = &mut foo;
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let _fn_ptr = foo as fn() -> u32;
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|
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println!("{:p}", &foo);
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println!("{:p}", &foo);
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//~^ WARN cast `foo` with `as *const fn() -> _` to use it as a pointer
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//~^ WARN cast `foo` with as fn() -> _` to use it as a pointer
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println!("{:p}", &bar);
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println!("{:p}", &bar);
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//~^ WARN cast `bar` with `as *const fn(_) -> _` to use it as a pointer
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//~^ WARN cast `bar` with as fn(_) -> _` to use it as a pointer
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println!("{:p}", &baz);
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println!("{:p}", &baz);
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//~^ WARN cast `baz` with `as *const fn(_, _) -> _` to use it as a pointer
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//~^ WARN cast `baz` with as fn(_, _) -> _` to use it as a pointer
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println!("{:p}", &unsafe_fn);
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//~^ WARN cast `baz` with as unsafe fn()` to use it as a pointer
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println!("{:p}", &c_fn);
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//~^ WARN cast `baz` with as extern "C" fn()` to use it as a pointer
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println!("{:p}", &unsafe_c_fn);
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//~^ WARN cast `baz` with as unsafe extern "C" fn()` to use it as a pointer
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println!("{:p}", &variadic_fn);
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//~^ WARN cast `baz` with as unsafe extern "C" fn(_, ...) -> _` to use it as a pointer
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println!("{:p}", &std::env::var::<String>);
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//~^ WARN cast `std::env::var` with as fn(_) -> _` to use it as a pointer
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|
|
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//should not produce any warnings
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println!("{:p}", foo as fn() -> u32);
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println!("{:p}", foo as *const fn() -> usize);
|
|
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println!("{:p}", bar as *const fn(usize) -> usize);
|
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println!("{:p}", baz as *const fn(usize, usize) -> usize);
|
|
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|
|
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//should not produce any warnings
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unsafe {
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let fn_thing = foo;
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std::mem::transmute::<_, usize>(&foo);
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println!("{:p}", &fn_thing);
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//~^ WARN cast `foo` with as fn() -> _` to use it as a pointer
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std::mem::transmute::<_, usize>(foo as fn() -> u32);
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}
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|
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(&bar)(1);
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call_fn(&bar, 1);
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parameterized_call_fn(&bar, 1);
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}
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}
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|
|
|
@ -1,22 +1,105 @@
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warning: cast `foo` with `as *const fn() -> _` to use it as a pointer
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warning: cast `foo` with `as fn() -> _` to use it as a pointer
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--> $DIR/function-references.rs:7:23
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--> $DIR/function-references.rs:16:20
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|
|
|
|
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LL | println!("{:p}", &foo);
|
LL | let _zst_ref = &foo;
|
||||||
| ^^^
|
| ^^^^
|
||||||
|
|
|
|
||||||
= note: `#[warn(function_references)]` on by default
|
= note: `#[warn(function_references)]` on by default
|
||||||
|
|
||||||
warning: cast `bar` with `as *const fn(_) -> _` to use it as a pointer
|
warning: cast `fn_item` with `as fn() -> _` to use it as a pointer
|
||||||
--> $DIR/function-references.rs:9:23
|
--> $DIR/function-references.rs:19:25
|
||||||
|
|
|
||||||
|
LL | let _indirect_ref = &fn_item;
|
||||||
|
| ^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:21:25
|
||||||
|
|
|
||||||
|
LL | let _cast_zst_ptr = &foo as *const _;
|
||||||
|
| ^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:23:38
|
||||||
|
|
|
||||||
|
LL | let _coerced_zst_ptr: *const _ = &foo;
|
||||||
|
| ^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:26:20
|
||||||
|
|
|
||||||
|
LL | let _zst_ref = &mut foo;
|
||||||
|
| ^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `mut_fn_item` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:29:25
|
||||||
|
|
|
||||||
|
LL | let _indirect_ref = &mut mut_fn_item;
|
||||||
|
| ^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:31:25
|
||||||
|
|
|
||||||
|
LL | let _cast_zst_ptr = &mut foo as *mut _;
|
||||||
|
| ^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:33:36
|
||||||
|
|
|
||||||
|
LL | let _coerced_zst_ptr: *mut _ = &mut foo;
|
||||||
|
| ^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:43:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &foo);
|
||||||
|
| ^^^^
|
||||||
|
|
||||||
|
warning: cast `bar` with `as fn(_) -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:45:22
|
||||||
|
|
|
|
||||||
LL | println!("{:p}", &bar);
|
LL | println!("{:p}", &bar);
|
||||||
| ^^^
|
| ^^^^
|
||||||
|
|
||||||
warning: cast `baz` with `as *const fn(_, _) -> _` to use it as a pointer
|
warning: cast `baz` with `as fn(_, _) -> _` to use it as a pointer
|
||||||
--> $DIR/function-references.rs:11:23
|
--> $DIR/function-references.rs:47:22
|
||||||
|
|
|
|
||||||
LL | println!("{:p}", &baz);
|
LL | println!("{:p}", &baz);
|
||||||
| ^^^
|
| ^^^^
|
||||||
|
|
||||||
warning: 3 warnings emitted
|
warning: cast `unsafe_fn` with `as unsafe fn()` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:49:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &unsafe_fn);
|
||||||
|
| ^^^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `c_fn` with `as extern "C" fn()` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:51:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &c_fn);
|
||||||
|
| ^^^^^
|
||||||
|
|
||||||
|
warning: cast `unsafe_c_fn` with `as unsafe extern "C" fn()` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:53:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &unsafe_c_fn);
|
||||||
|
| ^^^^^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `variadic_fn` with `as unsafe extern "C" fn(_, ...)` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:55:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &variadic_fn);
|
||||||
|
| ^^^^^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `std::env::var` with `as fn(_) -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:57:22
|
||||||
|
|
|
||||||
|
LL | println!("{:p}", &std::env::var::<String>);
|
||||||
|
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
||||||
|
|
||||||
|
warning: cast `foo` with `as fn() -> _` to use it as a pointer
|
||||||
|
--> $DIR/function-references.rs:63:41
|
||||||
|
|
|
||||||
|
LL | std::mem::transmute::<_, usize>(&foo);
|
||||||
|
| ^^^^
|
||||||
|
|
||||||
|
warning: 17 warnings emitted
|
||||||
|
|
Loading…
Add table
Add a link
Reference in a new issue