From 78d6b88f211cc9faf88815ce7fb1a91546cfce15 Mon Sep 17 00:00:00 2001
From: Jade <software@lfcode.ca>
Date: Fri, 14 May 2021 00:59:30 -0700
Subject: Add more tests, refactor array lengths/consteval work
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Fix #2922: add unknown length as a condition for a type having unknown.

Incorporate reviews:

* Extract some of the const evaluation workings into functions
* Add fixmes on the hacks
* Add tests for impls on specific array lengths (these work!!! 😁)
* Add tests for const generics (indeed we don't support it yet)
---
 crates/hir_ty/src/consteval.rs | 64 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 64 insertions(+)
 create mode 100644 crates/hir_ty/src/consteval.rs

(limited to 'crates/hir_ty/src/consteval.rs')

diff --git a/crates/hir_ty/src/consteval.rs b/crates/hir_ty/src/consteval.rs
new file mode 100644
index 000000000..a4a430f30
--- /dev/null
+++ b/crates/hir_ty/src/consteval.rs
@@ -0,0 +1,64 @@
+//! Constant evaluation details
+
+use std::convert::TryInto;
+
+use hir_def::{
+    builtin_type::BuiltinUint,
+    expr::{Expr, Literal},
+    type_ref::ConstScalar,
+};
+
+use crate::{Const, ConstData, ConstValue, Interner, TyKind};
+
+/// Extension trait for [`Const`]
+pub trait ConstExtension {
+    /// Is a [`Const`] unknown?
+    fn is_unknown(&self) -> bool;
+}
+
+impl ConstExtension for Const {
+    fn is_unknown(&self) -> bool {
+        match self.data(&Interner).value {
+            // interned Unknown
+            chalk_ir::ConstValue::Concrete(chalk_ir::ConcreteConst {
+                interned: ConstScalar::Unknown,
+            }) => true,
+
+            // interned concrete anything else
+            chalk_ir::ConstValue::Concrete(..) => false,
+
+            _ => {
+                log::error!("is_unknown was called on a non-concrete constant value! {:?}", self);
+                true
+            }
+        }
+    }
+}
+
+/// Extension trait for [`Expr`]
+pub trait ExprEval {
+    /// Attempts to evaluate the expression as a target usize.
+    fn eval_usize(&self) -> Option<u64>;
+}
+
+impl ExprEval for Expr {
+    // FIXME: support more than just evaluating literals
+    fn eval_usize(&self) -> Option<u64> {
+        match self {
+            Expr::Literal(Literal::Uint(v, None))
+            | Expr::Literal(Literal::Uint(v, Some(BuiltinUint::Usize))) => (*v).try_into().ok(),
+            _ => None,
+        }
+    }
+}
+
+/// Interns a possibly-unknown target usize
+pub fn usize_const(value: Option<u64>) -> Const {
+    ConstData {
+        ty: TyKind::Scalar(chalk_ir::Scalar::Uint(chalk_ir::UintTy::Usize)).intern(&Interner),
+        value: ConstValue::Concrete(chalk_ir::ConcreteConst {
+            interned: value.map(|value| ConstScalar::Usize(value)).unwrap_or(ConstScalar::Unknown),
+        }),
+    }
+    .intern(&Interner)
+}
-- 
cgit v1.2.3


From de0ed9860d86c3b905a967b1a7b5243499d32d67 Mon Sep 17 00:00:00 2001
From: Jade <software@lfcode.ca>
Date: Sat, 15 May 2021 18:51:18 -0700
Subject: Address final feedback

* rename ConstExtension->ConstExt
* refactor a manual construction of a Const
---
 crates/hir_ty/src/consteval.rs | 24 ++++++++----------------
 1 file changed, 8 insertions(+), 16 deletions(-)

(limited to 'crates/hir_ty/src/consteval.rs')

diff --git a/crates/hir_ty/src/consteval.rs b/crates/hir_ty/src/consteval.rs
index a4a430f30..e3ceb3d62 100644
--- a/crates/hir_ty/src/consteval.rs
+++ b/crates/hir_ty/src/consteval.rs
@@ -11,12 +11,12 @@ use hir_def::{
 use crate::{Const, ConstData, ConstValue, Interner, TyKind};
 
 /// Extension trait for [`Const`]
-pub trait ConstExtension {
+pub trait ConstExt {
     /// Is a [`Const`] unknown?
     fn is_unknown(&self) -> bool;
 }
 
-impl ConstExtension for Const {
+impl ConstExt for Const {
     fn is_unknown(&self) -> bool {
         match self.data(&Interner).value {
             // interned Unknown
@@ -35,20 +35,12 @@ impl ConstExtension for Const {
     }
 }
 
-/// Extension trait for [`Expr`]
-pub trait ExprEval {
-    /// Attempts to evaluate the expression as a target usize.
-    fn eval_usize(&self) -> Option<u64>;
-}
-
-impl ExprEval for Expr {
-    // FIXME: support more than just evaluating literals
-    fn eval_usize(&self) -> Option<u64> {
-        match self {
-            Expr::Literal(Literal::Uint(v, None))
-            | Expr::Literal(Literal::Uint(v, Some(BuiltinUint::Usize))) => (*v).try_into().ok(),
-            _ => None,
-        }
+// FIXME: support more than just evaluating literals
+pub fn eval_usize(expr: &Expr) -> Option<u64> {
+    match expr {
+        Expr::Literal(Literal::Uint(v, None))
+        | Expr::Literal(Literal::Uint(v, Some(BuiltinUint::Usize))) => (*v).try_into().ok(),
+        _ => None,
     }
 }
 
-- 
cgit v1.2.3