Merge pull request #1007 from JohnTitor/add-ices-2021-11

Add some ICEs

ices/88468.rs

@@ -0,0 +1,20 @@
+#![allow(incomplete_features)]
+#![feature(generic_const_exprs)]
+#![crate_type = "lib"]
+
+struct Assert<const COND: bool>;
+trait IsTrue {}
+impl IsTrue for Assert<true> {}
+
+trait IsNotZst {}
+
+impl<T> IsNotZst for T
+where
+    Assert<{ std::mem::size_of::<T>() > 0 }>: IsTrue,
+{}
+
+fn assert_not_zero_sized<T: IsNotZst>(_: T) {}
+
+fn main() {
+    assert_not_zero_sized(vec![1, 2, 3]);
+}

ices/88599.sh → ices/88599.rs

@@ -1,6 +1,4 @@
-#!/bin/bash
-
-rustc --crate-type lib - << EOF
+#![crate_type = "lib"]
 
 pub trait First {
     const CONST: bool;
@@ -18,5 +16,3 @@ pub trait Foo {
 impl <'a> Foo for () where &'a Self: Foo {
     const CONST: bool = <&Self>::CONST;
 }
-
-EOF

ices/88643.sh → ices/88643.rs

@@ -1,6 +1,4 @@
-#!/bin/bash
-
-rustc --crate-type lib - << EOF
+#![crate_type = "lib"]
 
 use std::collections::HashMap;
 
@@ -13,7 +11,3 @@ pub trait WidgetExt {
 }
 
 static CALLBACKS: HashMap<*const dyn WidgetExt, dyn FnMut(&mut _) + 'static> = HashMap::new();
-
-pub fn main() {}
-
-EOF

ices/89022-1.rs

@@ -0,0 +1,256 @@
+#![feature(adt_const_params)]
+#![feature(generic_const_exprs)]
+#![feature(const_fn_trait_bound)]
+
+use core::marker::PhantomData;
+use std::collections::HashMap;
+
+// const-evaluable equality for string slices
+pub const fn str_eq(lhs: &str, rhs: &str) -> bool {
+    let lhs_bytes = lhs.as_bytes();
+    let rhs_bytes = rhs.as_bytes();
+    let mut i = 0;
+    let bytes = if lhs_bytes.len() == rhs_bytes.len() {
+        lhs_bytes.len()
+    } else {
+        return false;
+    };
+
+    while i < bytes {
+        if lhs_bytes[i] != rhs_bytes[i] {
+            return false;
+        }
+        i += 1;
+    }
+    return true;
+}
+
+pub trait ContainsKey<const K: &'static str> {}
+
+// trait used to compare two types that have type-encoded lists of keys (in this cast static strings)
+pub trait KeySchema {
+    const KEYS: &'static [&'static str];
+    const SIZE: usize;
+}
+
+pub struct KeyNil;
+impl KeySchema for KeyNil {
+    const KEYS: &'static [&'static str] = &[];
+    const SIZE: usize = 0;
+}
+
+pub struct KeyCons<Tail, const KEY_ID: &'static str>
+where
+    Tail: KeySchema,
+{
+    _tail: PhantomData<Tail>,
+}
+
+pub const fn compute_successor_size<T: KeySchema>() -> usize {
+    T::SIZE + 1
+}
+
+pub const fn construct_successor_array<Tail: KeySchema>(
+    successor_key: &'static str,
+) -> [&'static str; compute_successor_size::<Tail>()]
+where
+    [&'static str; compute_successor_size::<Tail>()]: Sized,
+{
+    let mut keys = [""; compute_successor_size::<Tail>()];
+    let tail_keys = Tail::KEYS;
+    let mut i = 0;
+    let old_array_size: usize = compute_successor_size::<Tail>() - 1;
+    while i < old_array_size {
+        keys[i] = tail_keys[i];
+        i += 1;
+    }
+    keys[old_array_size] = successor_key;
+    keys
+}
+
+pub const fn is_equivalent_except<const K: &'static str>(
+    with_k: &[&'static str],
+    without_k: &[&'static str],
+) -> bool {
+    let mut i = 0;
+    while i < with_k.len() {
+        if str_eq(with_k[i], K) {
+            i += 1;
+            continue;
+        }
+        let mut j = 0;
+        let mut match_found = false;
+        while j < without_k.len() {
+            if str_eq(with_k[i], without_k[j]) {
+                match_found = true;
+                break;
+            }
+            j += 1;
+        }
+        if !match_found {
+            return false;
+        }
+        i += 1;
+    }
+    return true;
+}
+
+// Outputs a usize in order to make the array invalid by underflowing
+// Alternatively this could use const_panic to produce good error messages
+pub const fn check_valid_subset<S1: KeySchema, S2: KeySchema, const K: &'static str>() -> usize
+where
+    S1: ContainsKey<K>,
+{
+    let with_k: &[&'static str] = &S1::KEYS;
+    let without_k: &[&'static str] = &S2::KEYS;
+
+    if with_k.len() <= without_k.len() {
+        // panic because S1 isn't bigger
+        return (with_k.len() - 1) - without_k.len(); // panic using underflow
+    }
+
+    if !is_equivalent_except::<K>(with_k, without_k) {
+        // panic because S2 doesn't have the rest of S1's elements
+        return (without_k.len() - 1) - with_k.len(); // panic using underflow
+    }
+
+    return 1;
+}
+
+pub trait SubsetExcept<Parent: KeySchema, const K: &'static str>: KeySchema
+where
+    [(); Parent::SIZE - Self::SIZE]: Sized,
+    Parent: ContainsKey<K>,
+{
+}
+
+impl<Schema, PossibleParent, const K: &'static str> SubsetExcept<PossibleParent, K> for Schema
+where
+    Schema: KeySchema,
+    PossibleParent: KeySchema,
+    PossibleParent: ContainsKey<K>,
+    [(); PossibleParent::SIZE - Schema::SIZE]: Sized,
+    [(); check_valid_subset::<PossibleParent, Schema, K>()]: Sized,
+{
+}
+
+impl<Tail, const KEY_ID: &'static str> KeySchema for KeyCons<Tail, KEY_ID>
+where
+    Tail: KeySchema,
+    [(); compute_successor_size::<Tail>()]: Sized,
+{
+    const KEYS: &'static [&'static str] = &construct_successor_array::<Tail>(KEY_ID);
+    const SIZE: usize = compute_successor_size::<Tail>();
+}
+
+// thanks to matt1992#5582 on the Rust Programming Language Community Discord for offering this strategy
+// a const expression calls a function, which provides a "proof" that a given type should always use a given implementation
+pub trait ContainsKeyHelper<const IS_EQUAL: bool, const K: &'static str> {}
+
+const fn contains_key_helper_helper<const KEY_ID: &'static str, const K: &'static str>() -> bool {
+    str_eq(KEY_ID, K)
+}
+impl<Tail, const KEY_ID: &'static str, const K: &'static str> ContainsKey<K>
+    for KeyCons<Tail, KEY_ID>
+where
+    Tail: KeySchema,
+    Self: ContainsKeyHelper<{ contains_key_helper_helper::<KEY_ID, K>() }, K>,
+{
+}
+
+impl<Tail, const KEY_ID: &'static str, const K: &'static str> ContainsKeyHelper<false, K>
+    for KeyCons<Tail, KEY_ID>
+where
+    Tail: KeySchema + ContainsKey<K>,
+{
+}
+
+impl<Tail, const KEY_ID: &'static str, const K: &'static str> ContainsKeyHelper<true, K>
+    for KeyCons<Tail, KEY_ID>
+where
+    Tail: KeySchema,
+{
+}
+
+pub struct RestrictedStringMap<S: KeySchema> {
+    inner: HashMap<&'static str, Option<String>>,
+    // schemas should be 0-sized, but I use a phantom data here just to emphasize that there's no data dependency
+    _schema: PhantomData<S>,
+}
+impl<S: KeySchema, const K: &'static str> ContainsKey<K> for RestrictedStringMap<S> where
+    S: ContainsKey<K>
+{
+}
+impl<S: KeySchema> RestrictedStringMap<S>
+where
+    [(); compute_successor_size::<S>()]: Sized,
+{
+    pub fn empty_schema() -> RestrictedStringMap<KeyNil> {
+        RestrictedStringMap::<_> {
+            inner: HashMap::new(),
+            // schemas should be 0-sized, but I use a phantom data here just to emphasize that there's no data dependency
+            _schema: PhantomData::<_>,
+        }
+    }
+
+    pub fn new() -> Self {
+        let mut hm: HashMap<&'static str, Option<String>> = HashMap::new();
+
+        for k in S::KEYS {
+            hm.insert(*k, None);
+        }
+
+        hm.shrink_to_fit();
+
+        Self {
+            inner: hm,
+            _schema: PhantomData::<_>,
+        }
+    }
+
+    /// Adds a possible &'static str to the HashMap.
+    /// This requires consuming the map since our type must change to reflect the new schema.
+    pub fn add_key<const K: &'static str>(self) -> RestrictedStringMap<KeyCons<S, K>>
+    where
+        // Proof asserting that one size larger is still a valid schema
+        // this should only be untrue if the number of keys exceeds usize::MAX
+        [(); compute_successor_size::<S>()]: Sized,
+    {
+        let Self { mut inner, .. } = self;
+        inner.insert(K, None);
+        RestrictedStringMap::<_> {
+            inner: inner,
+            _schema: PhantomData::<_>,
+        }
+    }
+
+    // I don't know of a way to remove the &'static str other than having the user provide their own new schema.
+    // This is because I can't use a dependently typed function to construct a return type.
+    // That's the only way I can think of to compute what the return type of such a function would look like without user input.
+    //
+    pub fn remove_key<NewSchema: KeySchema, const K: &'static str>(
+        self,
+    ) -> RestrictedStringMap<NewSchema>
+    where
+        Self: ContainsKey<K>,
+        S: ContainsKey<K>,
+        NewSchema: SubsetExcept<S, K>,
+        [(); S::SIZE - NewSchema::SIZE]: Sized,
+    {
+        let Self { mut inner, .. } = self;
+        inner.remove(&K);
+        RestrictedStringMap::<_> {
+            inner: inner,
+            _schema: PhantomData::<_>,
+        }
+    }
+}
+
+fn foo() {
+    let map: RestrictedStringMap<KeyNil> = RestrictedStringMap::<KeyNil>::empty_schema();
+    let mut map: RestrictedStringMap<KeyCons<KeyCons<KeyNil, "k1">, "k2">> =
+        map.add_key::<"k1">().add_key::<"k2">();
+    let map: RestrictedStringMap<KeyCons<KeyNil, "k1">> = map.remove_key::<_, "k2">();
+}
+
+fn main() {}