mirror of https://github.com/rust-lang/rust.git
promotion: do not promote const-fn calls in const when that may fail without the entire const failing
This commit is contained in:
Ralf Jung
parent
40dcd796d0
commit
7183fa09bb
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@ -333,13 +333,6 @@ fn mir_promoted(
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body.tainted_by_errors = Some(error_reported);
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}
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let mut required_consts = Vec::new();
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let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
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for (bb, bb_data) in traversal::reverse_postorder(&body) {
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required_consts_visitor.visit_basic_block_data(bb, bb_data);
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}
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body.required_consts = required_consts;
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// What we need to run borrowck etc.
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let promote_pass = promote_consts::PromoteTemps::default();
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pm::run_passes(
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@ -349,6 +342,14 @@ fn mir_promoted(
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Some(MirPhase::Analysis(AnalysisPhase::Initial)),
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);
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// Promotion generates new consts; we run this after promotion to ensure they are accounted for.
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let mut required_consts = Vec::new();
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let mut required_consts_visitor = RequiredConstsVisitor::new(&mut required_consts);
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for (bb, bb_data) in traversal::reverse_postorder(&body) {
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required_consts_visitor.visit_basic_block_data(bb, bb_data);
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}
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body.required_consts = required_consts;
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let promoted = promote_pass.promoted_fragments.into_inner();
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(tcx.alloc_steal_mir(body), tcx.alloc_steal_promoted(promoted))
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}
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@ -13,6 +13,7 @@
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//! move analysis runs after promotion on broken MIR.
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use either::{Left, Right};
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use rustc_data_structures::fx::FxHashSet;
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use rustc_hir as hir;
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use rustc_middle::mir;
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use rustc_middle::mir::visit::{MutVisitor, MutatingUseContext, PlaceContext, Visitor};
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@ -175,6 +176,12 @@ fn collect_temps_and_candidates<'tcx>(
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struct Validator<'a, 'tcx> {
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ccx: &'a ConstCx<'a, 'tcx>,
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temps: &'a mut IndexSlice<Local, TempState>,
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/// For backwards compatibility, we are promoting function calls in `const`/`static`
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/// initializers. But we want to avoid evaluating code that might panic and that otherwise would
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/// not have been evaluated, so we only promote such calls in basic blocks that are guaranteed
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/// to execute. In other words, we only promote such calls in basic blocks that are definitely
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/// not dead code. Here we cache the result of computing that set of basic blocks.
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promotion_safe_blocks: Option<FxHashSet<BasicBlock>>,
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}
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impl<'a, 'tcx> std::ops::Deref for Validator<'a, 'tcx> {
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@ -260,7 +267,9 @@ impl<'tcx> Validator<'_, 'tcx> {
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self.validate_rvalue(rhs)
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}
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Right(terminator) => match &terminator.kind {
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TerminatorKind::Call { func, args, .. } => self.validate_call(func, args),
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TerminatorKind::Call { func, args, .. } => {
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self.validate_call(func, args, loc.block)
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}
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TerminatorKind::Yield { .. } => Err(Unpromotable),
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kind => {
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span_bug!(terminator.source_info.span, "{:?} not promotable", kind);
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@ -588,29 +597,79 @@ impl<'tcx> Validator<'_, 'tcx> {
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Ok(())
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}
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/// Computes the sets of blocks of this MIR that are definitely going to be executed
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/// if the function returns successfully. That makes it safe to promote calls in them
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/// that might fail.
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fn promotion_safe_blocks(body: &mir::Body<'tcx>) -> FxHashSet<BasicBlock> {
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let mut safe_blocks = FxHashSet::default();
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let mut safe_block = START_BLOCK;
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loop {
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safe_blocks.insert(safe_block);
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// Let's see if we can find another safe block.
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safe_block = match body.basic_blocks[safe_block].terminator().kind {
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TerminatorKind::Goto { target } => target,
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TerminatorKind::Call { target: Some(target), .. }
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| TerminatorKind::Drop { target, .. } => {
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// This calls a function or the destructor. `target` does not get executed if
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// the callee loops or panics. But in both cases the const already fails to
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// evaluate, so we are fine considering `target` a safe block for promotion.
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target
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}
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TerminatorKind::Assert { target, .. } => {
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// Similar to above, we only consider successful execution.
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target
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}
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_ => {
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// No next safe block.
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break;
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}
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};
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}
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safe_blocks
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}
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/// Returns whether the block is "safe" for promotion, which means it cannot be dead code.
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/// We use this to avoid promoting operations that can fail in dead code.
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fn is_promotion_safe_block(&mut self, block: BasicBlock) -> bool {
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let body = self.body;
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let safe_blocks =
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self.promotion_safe_blocks.get_or_insert_with(|| Self::promotion_safe_blocks(body));
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safe_blocks.contains(&block)
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}
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fn validate_call(
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&mut self,
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callee: &Operand<'tcx>,
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args: &[Spanned<Operand<'tcx>>],
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block: BasicBlock,
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) -> Result<(), Unpromotable> {
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let fn_ty = callee.ty(self.body, self.tcx);
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// Validate the operands. If they fail, there's no question -- we cannot promote.
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self.validate_operand(callee)?;
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for arg in args {
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self.validate_operand(&arg.node)?;
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}
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// Inside const/static items, we promote all (eligible) function calls.
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// Everywhere else, we require `#[rustc_promotable]` on the callee.
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let promote_all_const_fn = matches!(
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self.const_kind,
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Some(hir::ConstContext::Static(_) | hir::ConstContext::Const { inline: false })
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);
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if !promote_all_const_fn {
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if let ty::FnDef(def_id, _) = *fn_ty.kind() {
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// Never promote runtime `const fn` calls of
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// functions without `#[rustc_promotable]`.
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if !self.tcx.is_promotable_const_fn(def_id) {
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return Err(Unpromotable);
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}
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// Functions marked `#[rustc_promotable]` are explicitly allowed to be promoted, so we can
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// accept them at this point.
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let fn_ty = callee.ty(self.body, self.tcx);
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if let ty::FnDef(def_id, _) = *fn_ty.kind() {
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if self.tcx.is_promotable_const_fn(def_id) {
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return Ok(());
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}
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}
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// Ideally, we'd stop here and reject the rest.
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// But for backward compatibility, we have to accept some promotion in const/static
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// initializers. Inline consts are explicitly excluded, they are more recent so we have no
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// backwards compatibility reason to allow more promotion inside of them.
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let promote_all_fn = matches!(
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self.const_kind,
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Some(hir::ConstContext::Static(_) | hir::ConstContext::Const { inline: false })
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);
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if !promote_all_fn {
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return Err(Unpromotable);
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}
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// Make sure the callee is a `const fn`.
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let is_const_fn = match *fn_ty.kind() {
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ty::FnDef(def_id, _) => self.tcx.is_const_fn_raw(def_id),
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_ => false,
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@ -618,12 +677,13 @@ impl<'tcx> Validator<'_, 'tcx> {
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if !is_const_fn {
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return Err(Unpromotable);
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}
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self.validate_operand(callee)?;
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for arg in args {
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self.validate_operand(&arg.node)?;
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// The problem is, this may promote calls to functions that panic.
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// We don't want to introduce compilation errors if there's a panic in a call in dead code.
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// So we ensure that this is not dead code.
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if !self.is_promotion_safe_block(block) {
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return Err(Unpromotable);
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}
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// This passed all checks, so let's accept.
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Ok(())
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}
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}
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@ -634,7 +694,7 @@ fn validate_candidates(
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temps: &mut IndexSlice<Local, TempState>,
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candidates: &[Candidate],
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) -> Vec<Candidate> {
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let mut validator = Validator { ccx, temps };
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let mut validator = Validator { ccx, temps, promotion_safe_blocks: None };
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candidates
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.iter()
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@ -1,44 +0,0 @@
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warning: this arithmetic operation will overflow
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--> $DIR/promoted_errors.rs:15:5
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LL | 0 - 1
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| ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:9
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:19:5
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LL | 1 / 0
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| ^^^^^ attempt to divide `1_i32` by zero
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:30
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:23:5
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LL | 1 / (1 - 1)
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| ^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:27:5
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LL | 1 / (false as i32)
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| ^^^^^^^^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:31:5
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LL | [1, 2, 3][4]
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| ^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 4
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warning: 5 warnings emitted
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@ -1,44 +0,0 @@
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warning: this arithmetic operation will overflow
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--> $DIR/promoted_errors.rs:15:5
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LL | 0 - 1
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| ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:9
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:19:5
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LL | 1 / 0
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| ^^^^^ attempt to divide `1_i32` by zero
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:30
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:23:5
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LL | 1 / (1 - 1)
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| ^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:27:5
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LL | 1 / (false as i32)
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| ^^^^^^^^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:31:5
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LL | [1, 2, 3][4]
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| ^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 4
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warning: 5 warnings emitted
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@ -1,44 +0,0 @@
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warning: this arithmetic operation will overflow
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--> $DIR/promoted_errors.rs:15:5
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LL | 0 - 1
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| ^^^^^ attempt to compute `0_u32 - 1_u32`, which would overflow
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:9
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:19:5
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LL | 1 / 0
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| ^^^^^ attempt to divide `1_i32` by zero
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note: the lint level is defined here
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--> $DIR/promoted_errors.rs:11:30
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LL | #![warn(arithmetic_overflow, unconditional_panic)]
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| ^^^^^^^^^^^^^^^^^^^
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:23:5
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LL | 1 / (1 - 1)
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| ^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:27:5
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LL | 1 / (false as i32)
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| ^^^^^^^^^^^^^^^^^^ attempt to divide `1_i32` by zero
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warning: this operation will panic at runtime
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--> $DIR/promoted_errors.rs:31:5
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LL | [1, 2, 3][4]
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| ^^^^^^^^^^^^ index out of bounds: the length is 3 but the index is 4
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warning: 5 warnings emitted
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@ -1,52 +0,0 @@
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//@ revisions: noopt opt opt_with_overflow_checks
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//@[noopt]compile-flags: -C opt-level=0
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//@[opt]compile-flags: -O
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//@[opt_with_overflow_checks]compile-flags: -C overflow-checks=on -O
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//@ build-pass
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//@ ignore-pass (test emits codegen-time warnings and verifies that they are not errors)
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//! This test ensures that when we promote code that fails to evaluate, the build still succeeds.
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#![warn(arithmetic_overflow, unconditional_panic)]
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// The only way to have promoteds that fail is in `const fn` called from `const`/`static`.
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const fn overflow() -> u32 {
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0 - 1
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//~^ WARN this arithmetic operation will overflow
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}
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const fn div_by_zero1() -> i32 {
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1 / 0
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//~^ WARN this operation will panic at runtime
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}
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const fn div_by_zero2() -> i32 {
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1 / (1 - 1)
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//~^ WARN this operation will panic at runtime
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}
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const fn div_by_zero3() -> i32 {
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1 / (false as i32)
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//~^ WARN this operation will panic at runtime
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}
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const fn oob() -> i32 {
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[1, 2, 3][4]
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//~^ WARN this operation will panic at runtime
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}
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const fn mk_false() -> bool { false }
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// An actually used constant referencing failing promoteds in dead code.
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// This needs to always work.
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const Y: () = {
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if mk_false() {
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let _x: &'static u32 = &overflow();
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let _x: &'static i32 = &div_by_zero1();
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let _x: &'static i32 = &div_by_zero2();
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let _x: &'static i32 = &div_by_zero3();
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let _x: &'static i32 = &oob();
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}
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()
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};
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fn main() {
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Y;
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}
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@ -51,6 +51,15 @@ const TEST_DROP_NOT_PROMOTE: &String = {
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};
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// We do not promote function calls in `const` initializers in dead code.
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const fn mk_panic() -> u32 { panic!() }
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const fn mk_false() -> bool { false }
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const Y: () = {
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if mk_false() {
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let _x: &'static u32 = &mk_panic(); //~ ERROR temporary value dropped while borrowed
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}
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};
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fn main() {
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// We must not promote things with interior mutability. Not even if we "project it away".
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let _val: &'static _ = &(Cell::new(1), 2).0; //~ ERROR temporary value dropped while borrowed
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@ -47,6 +47,16 @@ LL | let x = &String::new();
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LL | };
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| - value is dropped here
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:59:33
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LL | let _x: &'static u32 = &mk_panic();
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| ------------ ^^^^^^^^^^ creates a temporary value which is freed while still in use
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| |
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| type annotation requires that borrow lasts for `'static`
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LL | }
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| - temporary value is freed at the end of this statement
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:21:32
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@ -68,7 +78,7 @@ LL | }
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| - temporary value is freed at the end of this statement
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:56:29
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--> $DIR/promote-not.rs:65:29
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LL | let _val: &'static _ = &(Cell::new(1), 2).0;
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| ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
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@ -79,7 +89,7 @@ LL | }
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| - temporary value is freed at the end of this statement
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:57:29
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--> $DIR/promote-not.rs:66:29
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LL | let _val: &'static _ = &(Cell::new(1), 2).1;
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| ---------- ^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
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@ -90,7 +100,7 @@ LL | }
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| - temporary value is freed at the end of this statement
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:60:29
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--> $DIR/promote-not.rs:69:29
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LL | let _val: &'static _ = &(1/0);
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| ---------- ^^^^^ creates a temporary value which is freed while still in use
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@ -101,7 +111,7 @@ LL | }
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| - temporary value is freed at the end of this statement
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error[E0716]: temporary value dropped while borrowed
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--> $DIR/promote-not.rs:61:29
|
||||
--> $DIR/promote-not.rs:70:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(1/(1-1));
|
||||
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -112,7 +122,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:62:29
|
||||
--> $DIR/promote-not.rs:71:29
|
||||
|
|
||||
LL | let _val: &'static _ = &((1+1)/(1-1));
|
||||
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -123,7 +133,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:63:29
|
||||
--> $DIR/promote-not.rs:72:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(i32::MIN/-1);
|
||||
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -134,7 +144,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:64:29
|
||||
--> $DIR/promote-not.rs:73:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(i32::MIN/(0-1));
|
||||
| ---------- ^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -145,7 +155,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:65:29
|
||||
--> $DIR/promote-not.rs:74:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(-128i8/-1);
|
||||
| ---------- ^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -156,7 +166,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:66:29
|
||||
--> $DIR/promote-not.rs:75:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(1%0);
|
||||
| ---------- ^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -167,7 +177,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:67:29
|
||||
--> $DIR/promote-not.rs:76:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(1%(1-1));
|
||||
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -178,7 +188,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:68:29
|
||||
--> $DIR/promote-not.rs:77:29
|
||||
|
|
||||
LL | let _val: &'static _ = &([1,2,3][4]+1);
|
||||
| ---------- ^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -189,7 +199,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:72:29
|
||||
--> $DIR/promote-not.rs:81:29
|
||||
|
|
||||
LL | let _val: &'static _ = &TEST_DROP;
|
||||
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -200,7 +210,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:74:29
|
||||
--> $DIR/promote-not.rs:83:29
|
||||
|
|
||||
LL | let _val: &'static _ = &&TEST_DROP;
|
||||
| ---------- ^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -211,7 +221,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:74:30
|
||||
--> $DIR/promote-not.rs:83:30
|
||||
|
|
||||
LL | let _val: &'static _ = &&TEST_DROP;
|
||||
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -222,7 +232,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:77:29
|
||||
--> $DIR/promote-not.rs:86:29
|
||||
|
|
||||
LL | let _val: &'static _ = &(&TEST_DROP,);
|
||||
| ---------- ^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -233,7 +243,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:77:31
|
||||
--> $DIR/promote-not.rs:86:31
|
||||
|
|
||||
LL | let _val: &'static _ = &(&TEST_DROP,);
|
||||
| ---------- ^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -244,7 +254,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:80:29
|
||||
--> $DIR/promote-not.rs:89:29
|
||||
|
|
||||
LL | let _val: &'static _ = &[&TEST_DROP; 1];
|
||||
| ---------- ^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -255,7 +265,7 @@ LL | }
|
|||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:80:31
|
||||
--> $DIR/promote-not.rs:89:31
|
||||
|
|
||||
LL | let _val: &'static _ = &[&TEST_DROP; 1];
|
||||
| ---------- ^^^^^^^^^ - temporary value is freed at the end of this statement
|
||||
|
|
@ -264,7 +274,7 @@ LL | let _val: &'static _ = &[&TEST_DROP; 1];
|
|||
| type annotation requires that borrow lasts for `'static`
|
||||
|
||||
error[E0716]: temporary value dropped while borrowed
|
||||
--> $DIR/promote-not.rs:89:26
|
||||
--> $DIR/promote-not.rs:98:26
|
||||
|
|
||||
LL | let x: &'static _ = &UnionWithCell { f1: 0 };
|
||||
| ---------- ^^^^^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
|
||||
|
|
@ -274,7 +284,7 @@ LL |
|
|||
LL | }
|
||||
| - temporary value is freed at the end of this statement
|
||||
|
||||
error: aborting due to 26 previous errors
|
||||
error: aborting due to 27 previous errors
|
||||
|
||||
Some errors have detailed explanations: E0493, E0716.
|
||||
For more information about an error, try `rustc --explain E0493`.
|
||||
|
|
|
|||
|
|
@ -5,28 +5,30 @@
|
|||
|
||||
//@ build-pass
|
||||
|
||||
#![allow(arithmetic_overflow)]
|
||||
|
||||
use std::mem;
|
||||
|
||||
const fn assert_static<T>(_: &'static T) {}
|
||||
|
||||
#[allow(unconditional_panic)]
|
||||
const fn fail() -> i32 {
|
||||
1/0
|
||||
}
|
||||
const C: i32 = {
|
||||
// Promoted that fails to evaluate in dead code -- this must work
|
||||
// (for backwards compatibility reasons).
|
||||
if false {
|
||||
assert_static(&fail());
|
||||
}
|
||||
// Function calls in const on the "main path" (not inside conditionals)
|
||||
// do get promoted.
|
||||
const fn make_thing() -> i32 {
|
||||
42
|
||||
}
|
||||
const C: () = {
|
||||
assert_static(&make_thing());
|
||||
// Make sure this works even when there's other stuff (like function calls) above the relevant
|
||||
// call in the const initializer.
|
||||
assert_static(&make_thing());
|
||||
};
|
||||
|
||||
fn main() {
|
||||
assert_static(&["a", "b", "c"]);
|
||||
assert_static(&["d", "e", "f"]);
|
||||
assert_eq!(C, 42);
|
||||
|
||||
// make sure that this does not cause trouble despite overflowing
|
||||
assert_static(&(0-1));
|
||||
assert_static(&(0u32 - 1));
|
||||
|
||||
// div-by-non-0 (and also not MIN/-1) is okay
|
||||
assert_static(&(1/1));
|
||||
|
|
@ -36,12 +38,16 @@ fn main() {
|
|||
assert_static(&(1%1));
|
||||
|
||||
// in-bounds array access is okay
|
||||
assert_static(&([1,2,3][0] + 1));
|
||||
assert_static(&[[1,2][1]]);
|
||||
assert_static(&([1, 2, 3][0] + 1));
|
||||
assert_static(&[[1, 2][1]]);
|
||||
|
||||
// Top-level projections are not part of the promoted, so no error here.
|
||||
if false {
|
||||
#[allow(unconditional_panic)]
|
||||
assert_static(&[1,2,3][4]);
|
||||
assert_static(&[1, 2, 3][4]);
|
||||
}
|
||||
|
||||
// More complicated case involving control flow and a `#[rustc_promotable]` function
|
||||
let decision = std::hint::black_box(true);
|
||||
let x: &'static usize = if decision { &mem::size_of::<usize>() } else { &0 };
|
||||
}
|
||||
|
|
|
|||
|
|
@ -4,7 +4,7 @@ fn non_elidable<'a, 'b>(a: &'a u8, b: &'b u8) -> &'a u8 {
|
|||
a
|
||||
}
|
||||
|
||||
// The incorrect case without `for<'a>` is tested for in `rfc1623-2.rs`
|
||||
// The incorrect case without `for<'a>` is tested for in `rfc1623-3.rs`
|
||||
static NON_ELIDABLE_FN: &for<'a> fn(&'a u8, &'a u8) -> &'a u8 =
|
||||
&(non_elidable as for<'a> fn(&'a u8, &'a u8) -> &'a u8);
|
||||
|
||||
|
|
@ -26,10 +26,14 @@ static SOME_STRUCT: &SomeStruct = &SomeStruct {
|
|||
foo: &Foo { bools: &[false, true] },
|
||||
bar: &Bar { bools: &[true, true] },
|
||||
f: &id,
|
||||
//~^ ERROR implementation of `Fn` is not general enough
|
||||
//~^ ERROR mismatched types
|
||||
//~| ERROR mismatched types
|
||||
//~| ERROR mismatched types
|
||||
//~| ERROR mismatched types
|
||||
//~| ERROR implementation of `Fn` is not general enough
|
||||
//~| ERROR implementation of `Fn` is not general enough
|
||||
//~| ERROR implementation of `Fn` is not general enough
|
||||
//~| ERROR implementation of `Fn` is not general enough
|
||||
//~| ERROR implementation of `FnOnce` is not general enough
|
||||
//~| ERROR implementation of `FnOnce` is not general enough
|
||||
};
|
||||
|
||||
// very simple test for a 'static static with default lifetime
|
||||
|
|
|
|||
|
|
@ -34,5 +34,45 @@ LL | f: &id,
|
|||
= note: `fn(&Foo<'2>) -> &Foo<'2> {id::<&Foo<'2>>}` must implement `FnOnce<(&'a Foo<'1>,)>`, for any lifetime `'1`...
|
||||
= note: ...but it actually implements `FnOnce<(&Foo<'2>,)>`, for some specific lifetime `'2`
|
||||
|
||||
error: aborting due to 4 previous errors
|
||||
error[E0308]: mismatched types
|
||||
--> $DIR/rfc1623-2.rs:28:8
|
||||
|
|
||||
LL | f: &id,
|
||||
| ^^^ one type is more general than the other
|
||||
|
|
||||
= note: expected trait `for<'a, 'b> Fn(&'a Foo<'b>)`
|
||||
found trait `Fn(&Foo<'_>)`
|
||||
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
|
||||
|
||||
error[E0308]: mismatched types
|
||||
--> $DIR/rfc1623-2.rs:28:8
|
||||
|
|
||||
LL | f: &id,
|
||||
| ^^^ one type is more general than the other
|
||||
|
|
||||
= note: expected trait `for<'a, 'b> Fn(&'a Foo<'b>)`
|
||||
found trait `Fn(&Foo<'_>)`
|
||||
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
|
||||
|
||||
error: implementation of `FnOnce` is not general enough
|
||||
--> $DIR/rfc1623-2.rs:28:8
|
||||
|
|
||||
LL | f: &id,
|
||||
| ^^^ implementation of `FnOnce` is not general enough
|
||||
|
|
||||
= note: `fn(&'2 Foo<'_>) -> &'2 Foo<'_> {id::<&'2 Foo<'_>>}` must implement `FnOnce<(&'1 Foo<'b>,)>`, for any lifetime `'1`...
|
||||
= note: ...but it actually implements `FnOnce<(&'2 Foo<'_>,)>`, for some specific lifetime `'2`
|
||||
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
|
||||
|
||||
error: implementation of `FnOnce` is not general enough
|
||||
--> $DIR/rfc1623-2.rs:28:8
|
||||
|
|
||||
LL | f: &id,
|
||||
| ^^^ implementation of `FnOnce` is not general enough
|
||||
|
|
||||
= note: `fn(&Foo<'2>) -> &Foo<'2> {id::<&Foo<'2>>}` must implement `FnOnce<(&'a Foo<'1>,)>`, for any lifetime `'1`...
|
||||
= note: ...but it actually implements `FnOnce<(&Foo<'2>,)>`, for some specific lifetime `'2`
|
||||
= note: duplicate diagnostic emitted due to `-Z deduplicate-diagnostics=no`
|
||||
|
||||
error: aborting due to 8 previous errors
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue