Add basic support for array lengths in types

This recognizes `let a = [1u8, 2, 3]` as having type `[u8; 3]` instead
of the previous `[u8; _]`. Byte strings and `[0u8; 2]` kinds of range
array declarations are unsupported as before.

I don't know why a bunch of our rustc tests had single quotes inside
strings un-escaped by `UPDATE_EXPECT=1 cargo t`, but I don't think it's
bad? Maybe something in a nightly?

1 files changed, 5 insertions, 2 deletions

diff --git a/crates/hir_ty/src/lib.rs b/crates/hir_ty/src/lib.rs
index 0505fa4ae..d23eff513 100644
--- a/crates/hir_ty/src/lib.rs
+++ b/crates/hir_ty/src/lib.rs
@@ -12,6 +12,7 @@ mod chalk_db;
 mod chalk_ext;
 mod infer;
 mod interner;
+mod consts;
 mod lower;
 mod mapping;
 mod op;
@@ -39,7 +40,7 @@ use chalk_ir::{
 };
 use hir_def::{expr::ExprId, type_ref::Rawness, TypeParamId};
 
-use crate::{db::HirDatabase, display::HirDisplay, utils::generics};
+use crate::{consts::ConstScalar, db::HirDatabase, display::HirDisplay, utils::generics};
 
 pub use autoderef::autoderef;
 pub use builder::TyBuilder;
@@ -250,7 +251,9 @@ pub fn dummy_usize_const() -> Const {
     let usize_ty = chalk_ir::TyKind::Scalar(Scalar::Uint(UintTy::Usize)).intern(&Interner);
     chalk_ir::ConstData {
         ty: usize_ty,
-        value: chalk_ir::ConstValue::Concrete(chalk_ir::ConcreteConst { interned: () }),
+        value: chalk_ir::ConstValue::Concrete(chalk_ir::ConcreteConst {
+            interned: ConstScalar::Unknown,
+        }),
     }
     .intern(&Interner)
 }