bendns' repos / rust-analyzer
Unnamed repository; edit this file 'description' to name the repository.
Diffstat (limited to 'crates/hir_ty/src/consteval.rs')
-rw-r--r--crates/hir_ty/src/consteval.rs89
1 files changed, 87 insertions, 2 deletions
diff --git a/crates/hir_ty/src/consteval.rs b/crates/hir_ty/src/consteval.rs
index 5cc474aca6..24296c6b7b 100644
--- a/crates/hir_ty/src/consteval.rs
+++ b/crates/hir_ty/src/consteval.rs
@@ -2,15 +2,25 @@
use std::{collections::HashMap, convert::TryInto, fmt::Display};
-use chalk_ir::{IntTy, Scalar};
+use chalk_ir::{BoundVar, DebruijnIndex, GenericArgData, IntTy, Scalar};
use hir_def::{
expr::{ArithOp, BinaryOp, Expr, Literal, Pat},
+ path::ModPath,
+ resolver::{Resolver, ValueNs},
type_ref::ConstScalar,
};
use hir_expand::name::Name;
use la_arena::{Arena, Idx};
+use stdx::never;
-use crate::{Const, ConstData, ConstValue, Interner, Ty, TyKind};
+use crate::{
+ db::HirDatabase,
+ infer::{Expectation, InferenceContext},
+ lower::ParamLoweringMode,
+ to_placeholder_idx,
+ utils::Generics,
+ Const, ConstData, ConstValue, GenericArg, Interner, Ty, TyKind,
+};
/// Extension trait for [`Const`]
pub trait ConstExt {
@@ -303,6 +313,57 @@ pub fn eval_usize(expr: Idx<Expr>, mut ctx: ConstEvalCtx<'_>) -> Option<u64> {
None
}
+pub(crate) fn path_to_const(
+ db: &dyn HirDatabase,
+ resolver: &Resolver,
+ path: &ModPath,
+ mode: ParamLoweringMode,
+ args_lazy: impl FnOnce() -> Generics,
+ debruijn: DebruijnIndex,
+) -> Option<Const> {
+ match resolver.resolve_path_in_value_ns_fully(db.upcast(), &path) {
+ Some(ValueNs::GenericParam(p)) => {
+ let ty = db.const_param_ty(p);
+ let args = args_lazy();
+ let value = match mode {
+ ParamLoweringMode::Placeholder => {
+ ConstValue::Placeholder(to_placeholder_idx(db, p.into()))
+ }
+ ParamLoweringMode::Variable => match args.param_idx(p.into()) {
+ Some(x) => ConstValue::BoundVar(BoundVar::new(debruijn, x)),
+ None => {
+ never!(
+ "Generic list doesn't contain this param: {:?}, {}, {:?}",
+ args,
+ path,
+ p
+ );
+ return None;
+ }
+ },
+ };
+ Some(ConstData { ty, value }.intern(Interner))
+ }
+ _ => None,
+ }
+}
+
+pub fn unknown_const(ty: Ty) -> Const {
+ ConstData {
+ ty,
+ value: ConstValue::Concrete(chalk_ir::ConcreteConst { interned: ConstScalar::Unknown }),
+ }
+ .intern(Interner)
+}
+
+pub fn unknown_const_usize() -> Const {
+ unknown_const(TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::Usize)).intern(Interner))
+}
+
+pub fn unknown_const_as_generic(ty: Ty) -> GenericArg {
+ GenericArgData::Const(unknown_const(ty)).intern(Interner)
+}
+
/// Interns a possibly-unknown target usize
pub fn usize_const(value: Option<u64>) -> Const {
ConstData {
@@ -313,3 +374,27 @@ pub fn usize_const(value: Option<u64>) -> Const {
}
.intern(Interner)
}
+
+pub(crate) fn eval_to_const(
+ expr: Idx<Expr>,
+ mode: ParamLoweringMode,
+ ctx: &mut InferenceContext,
+ args: impl FnOnce() -> Generics,
+ debruijn: DebruijnIndex,
+) -> Const {
+ if let Expr::Path(p) = &ctx.body.exprs[expr] {
+ let db = ctx.db;
+ let resolver = &ctx.resolver;
+ if let Some(c) = path_to_const(db, resolver, p.mod_path(), mode, args, debruijn) {
+ return c;
+ }
+ }
+ let body = ctx.body.clone();
+ let ctx = ConstEvalCtx {
+ exprs: &body.exprs,
+ pats: &body.pats,
+ local_data: HashMap::default(),
+ infer: &mut |x| ctx.infer_expr(x, &Expectation::None),
+ };
+ usize_const(eval_usize(expr, ctx))
+}