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-rw-r--r--compiler/rustc_ty_utils/src/consts.rs195
1 files changed, 90 insertions, 105 deletions
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index 7c2f4db94..44c4fc48d 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -11,6 +11,8 @@ use rustc_target::abi::VariantIdx;
use std::iter;
+use crate::errors::{GenericConstantTooComplex, GenericConstantTooComplexSub};
+
/// Destructures array, ADT or tuple constants into the constants
/// of their fields.
pub(crate) fn destructure_const<'tcx>(
@@ -93,26 +95,25 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
self.body.exprs[self.body_id].span
}
- fn error(&mut self, span: Span, msg: &str) -> Result<!, ErrorGuaranteed> {
- let reported = self
- .tcx
- .sess
- .struct_span_err(self.root_span(), "overly complex generic constant")
- .span_label(span, msg)
- .help("consider moving this anonymous constant into a `const` function")
- .emit();
+ fn error(&mut self, sub: GenericConstantTooComplexSub) -> Result<!, ErrorGuaranteed> {
+ let reported = self.tcx.sess.emit_err(GenericConstantTooComplex {
+ span: self.root_span(),
+ maybe_supported: None,
+ sub,
+ });
Err(reported)
}
- fn maybe_supported_error(&mut self, span: Span, msg: &str) -> Result<!, ErrorGuaranteed> {
- let reported = self
- .tcx
- .sess
- .struct_span_err(self.root_span(), "overly complex generic constant")
- .span_label(span, msg)
- .help("consider moving this anonymous constant into a `const` function")
- .note("this operation may be supported in the future")
- .emit();
+
+ fn maybe_supported_error(
+ &mut self,
+ sub: GenericConstantTooComplexSub,
+ ) -> Result<!, ErrorGuaranteed> {
+ let reported = self.tcx.sess.emit_err(GenericConstantTooComplex {
+ span: self.root_span(),
+ maybe_supported: Some(()),
+ sub,
+ });
Err(reported)
}
@@ -154,9 +155,9 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
return true;
}
- match pat.kind.as_ref() {
+ match pat.kind {
thir::PatKind::Constant { value } => value.has_param_types_or_consts(),
- thir::PatKind::Range(thir::PatRange { lo, hi, .. }) => {
+ thir::PatKind::Range(box thir::PatRange { lo, hi, .. }) => {
lo.has_param_types_or_consts() || hi.has_param_types_or_consts()
}
_ => false,
@@ -221,17 +222,6 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
debug!("AbstractConstBuilder::build: body={:?}", &*self.body);
self.recurse_build(self.body_id)?;
- for n in self.nodes.iter() {
- if let Node::Leaf(ct) = n {
- if let ty::ConstKind::Unevaluated(ct) = ct.kind() {
- // `AbstractConst`s should not contain any promoteds as they require references which
- // are not allowed.
- assert_eq!(ct.promoted, None);
- assert_eq!(ct, self.tcx.erase_regions(ct));
- }
- }
- }
-
Ok(self.tcx.arena.alloc_from_iter(self.nodes.into_iter()))
}
@@ -243,22 +233,23 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
&ExprKind::Scope { value, .. } => self.recurse_build(value)?,
&ExprKind::PlaceTypeAscription { source, .. }
| &ExprKind::ValueTypeAscription { source, .. } => self.recurse_build(source)?,
- &ExprKind::Literal { lit, neg} => {
+ &ExprKind::Literal { lit, neg } => {
let sp = node.span;
- let constant =
- match self.tcx.at(sp).lit_to_const(LitToConstInput { lit: &lit.node, ty: node.ty, neg }) {
- Ok(c) => c,
- Err(LitToConstError::Reported) => {
- self.tcx.const_error(node.ty)
- }
- Err(LitToConstError::TypeError) => {
- bug!("encountered type error in lit_to_const")
- }
- };
+ let constant = match self.tcx.at(sp).lit_to_const(LitToConstInput {
+ lit: &lit.node,
+ ty: node.ty,
+ neg,
+ }) {
+ Ok(c) => c,
+ Err(LitToConstError::Reported) => self.tcx.const_error(node.ty),
+ Err(LitToConstError::TypeError) => {
+ bug!("encountered type error in lit_to_const")
+ }
+ };
self.nodes.push(Node::Leaf(constant))
}
- &ExprKind::NonHirLiteral { lit , user_ty: _} => {
+ &ExprKind::NonHirLiteral { lit, user_ty: _ } => {
let val = ty::ValTree::from_scalar_int(lit);
self.nodes.push(Node::Leaf(ty::Const::from_value(self.tcx, val, node.ty)))
}
@@ -269,19 +260,17 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
&ExprKind::NamedConst { def_id, substs, user_ty: _ } => {
let uneval = ty::Unevaluated::new(ty::WithOptConstParam::unknown(def_id), substs);
- let constant = self.tcx.mk_const(ty::ConstS {
- kind: ty::ConstKind::Unevaluated(uneval),
- ty: node.ty,
- });
+ let constant = self
+ .tcx
+ .mk_const(ty::ConstS { kind: ty::ConstKind::Unevaluated(uneval), ty: node.ty });
self.nodes.push(Node::Leaf(constant))
}
- ExprKind::ConstParam {param, ..} => {
- let const_param = self.tcx.mk_const(ty::ConstS {
- kind: ty::ConstKind::Param(*param),
- ty: node.ty,
- });
+ ExprKind::ConstParam { param, .. } => {
+ let const_param = self
+ .tcx
+ .mk_const(ty::ConstS { kind: ty::ConstKind::Param(*param), ty: node.ty });
self.nodes.push(Node::Leaf(const_param))
}
@@ -311,8 +300,15 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
// bar::<{ N + 1 }>();
// }
// ```
- ExprKind::Block { body: thir::Block { stmts: box [], expr: Some(e), .. } } => {
- self.recurse_build(*e)?
+ ExprKind::Block { block } => {
+ if let thir::Block { stmts: box [], expr: Some(e), .. } = &self.body.blocks[*block]
+ {
+ self.recurse_build(*e)?
+ } else {
+ self.maybe_supported_error(GenericConstantTooComplexSub::BlockNotSupported(
+ node.span,
+ ))?
+ }
}
// `ExprKind::Use` happens when a `hir::ExprKind::Cast` is a
// "coercion cast" i.e. using a coercion or is a no-op.
@@ -325,7 +321,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
let arg = self.recurse_build(source)?;
self.nodes.push(Node::Cast(CastKind::As, arg, node.ty))
}
- ExprKind::Borrow{ arg, ..} => {
+ ExprKind::Borrow { arg, .. } => {
let arg_node = &self.body.exprs[*arg];
// Skip reborrows for now until we allow Deref/Borrow/AddressOf
@@ -334,80 +330,69 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
if let ExprKind::Deref { arg } = arg_node.kind {
self.recurse_build(arg)?
} else {
- self.maybe_supported_error(
+ self.maybe_supported_error(GenericConstantTooComplexSub::BorrowNotSupported(
node.span,
- "borrowing is not supported in generic constants",
- )?
+ ))?
}
}
// FIXME(generic_const_exprs): We may want to support these.
- ExprKind::AddressOf { .. } | ExprKind::Deref {..}=> self.maybe_supported_error(
- node.span,
- "dereferencing or taking the address is not supported in generic constants",
- )?,
- ExprKind::Repeat { .. } | ExprKind::Array { .. } => self.maybe_supported_error(
- node.span,
- "array construction is not supported in generic constants",
+ ExprKind::AddressOf { .. } | ExprKind::Deref { .. } => self.maybe_supported_error(
+ GenericConstantTooComplexSub::AddressAndDerefNotSupported(node.span),
)?,
- ExprKind::Block { .. } => self.maybe_supported_error(
- node.span,
- "blocks are not supported in generic constant",
+ ExprKind::Repeat { .. } | ExprKind::Array { .. } => self.maybe_supported_error(
+ GenericConstantTooComplexSub::ArrayNotSupported(node.span),
)?,
ExprKind::NeverToAny { .. } => self.maybe_supported_error(
- node.span,
- "converting nevers to any is not supported in generic constant",
+ GenericConstantTooComplexSub::NeverToAnyNotSupported(node.span),
)?,
ExprKind::Tuple { .. } => self.maybe_supported_error(
- node.span,
- "tuple construction is not supported in generic constants",
+ GenericConstantTooComplexSub::TupleNotSupported(node.span),
)?,
ExprKind::Index { .. } => self.maybe_supported_error(
- node.span,
- "indexing is not supported in generic constant",
+ GenericConstantTooComplexSub::IndexNotSupported(node.span),
)?,
ExprKind::Field { .. } => self.maybe_supported_error(
- node.span,
- "field access is not supported in generic constant",
+ GenericConstantTooComplexSub::FieldNotSupported(node.span),
)?,
ExprKind::ConstBlock { .. } => self.maybe_supported_error(
- node.span,
- "const blocks are not supported in generic constant",
- )?,
- ExprKind::Adt(_) => self.maybe_supported_error(
- node.span,
- "struct/enum construction is not supported in generic constants",
+ GenericConstantTooComplexSub::ConstBlockNotSupported(node.span),
)?,
+ ExprKind::Adt(_) => self
+ .maybe_supported_error(GenericConstantTooComplexSub::AdtNotSupported(node.span))?,
// dont know if this is correct
- ExprKind::Pointer { .. } =>
- self.error(node.span, "pointer casts are not allowed in generic constants")?,
- ExprKind::Yield { .. } =>
- self.error(node.span, "generator control flow is not allowed in generic constants")?,
- ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => self
- .error(
- node.span,
- "loops and loop control flow are not supported in generic constants",
- )?,
- ExprKind::Box { .. } =>
- self.error(node.span, "allocations are not allowed in generic constants")?,
+ ExprKind::Pointer { .. } => {
+ self.error(GenericConstantTooComplexSub::PointerNotSupported(node.span))?
+ }
+ ExprKind::Yield { .. } => {
+ self.error(GenericConstantTooComplexSub::YieldNotSupported(node.span))?
+ }
+ ExprKind::Continue { .. } | ExprKind::Break { .. } | ExprKind::Loop { .. } => {
+ self.error(GenericConstantTooComplexSub::LoopNotSupported(node.span))?
+ }
+ ExprKind::Box { .. } => {
+ self.error(GenericConstantTooComplexSub::BoxNotSupported(node.span))?
+ }
ExprKind::Unary { .. } => unreachable!(),
// we handle valid unary/binary ops above
- ExprKind::Binary { .. } =>
- self.error(node.span, "unsupported binary operation in generic constants")?,
- ExprKind::LogicalOp { .. } =>
- self.error(node.span, "unsupported operation in generic constants, short-circuiting operations would imply control flow")?,
+ ExprKind::Binary { .. } => {
+ self.error(GenericConstantTooComplexSub::BinaryNotSupported(node.span))?
+ }
+ ExprKind::LogicalOp { .. } => {
+ self.error(GenericConstantTooComplexSub::LogicalOpNotSupported(node.span))?
+ }
ExprKind::Assign { .. } | ExprKind::AssignOp { .. } => {
- self.error(node.span, "assignment is not supported in generic constants")?
+ self.error(GenericConstantTooComplexSub::AssignNotSupported(node.span))?
+ }
+ ExprKind::Closure { .. } | ExprKind::Return { .. } => {
+ self.error(GenericConstantTooComplexSub::ClosureAndReturnNotSupported(node.span))?
}
- ExprKind::Closure { .. } | ExprKind::Return { .. } => self.error(
- node.span,
- "closures and function keywords are not supported in generic constants",
- )?,
// let expressions imply control flow
- ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } =>
- self.error(node.span, "control flow is not supported in generic constants")?,
+ ExprKind::Match { .. } | ExprKind::If { .. } | ExprKind::Let { .. } => {
+ self.error(GenericConstantTooComplexSub::ControlFlowNotSupported(node.span))?
+ }
ExprKind::InlineAsm { .. } => {
- self.error(node.span, "assembly is not supported in generic constants")?
+ self.error(GenericConstantTooComplexSub::InlineAsmNotSupported(node.span))?
}
// we dont permit let stmts so `VarRef` and `UpvarRef` cant happen
@@ -415,7 +400,7 @@ impl<'a, 'tcx> AbstractConstBuilder<'a, 'tcx> {
| ExprKind::UpvarRef { .. }
| ExprKind::StaticRef { .. }
| ExprKind::ThreadLocalRef(_) => {
- self.error(node.span, "unsupported operation in generic constant")?
+ self.error(GenericConstantTooComplexSub::OperationNotSupported(node.span))?
}
})
}