Merge pull request #48 from rodrimati1992/fix_fn_promotion

0.9.2 release

.github/workflows/rust.yml

@@ -79,7 +79,7 @@ jobs:
         cargo test
 
         cd "${{github.workspace}}/abi_stable"
-        cargo test --features "testing sabi_trait_examples"
+        cargo test --features "testing sabi_trait_examples test_const_params"
 
         cd "${{github.workspace}}/examples/0_modules_and_interface_types/impl/"
         cargo test

Changelog.md

@@ -2,9 +2,20 @@ This is the changelog,summarising changes in each version(some minor changes may
 
 # 0.9
 
+# 0.9.2
+
+Added impls of StableAbi for arrays of all sizes, conditional on the "const_params" feature.
+
+Made abi_stable more resilient to changes in how static promotion works.
+
+Documented that staticref only supports declaring inherent associated constants,
+but doesn't stop compiling anywhere else yet.
+
+Moved continuous integration testing to github.
+
 # 0.9.1
 
-Fixed a memory safety bug in RString::retain and RVec::retain.
+Fixed a memory safety bug in `RString::retain` and `RVec::retain`.
 
 # 0.9.0
 

abi_stable/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "abi_stable"
-version = "0.9.1"
+version = "0.9.2"
 authors = ["rodrimati1992 <[email protected]>"]
 edition="2018"
 license = "MIT/Apache-2.0"
@@ -34,20 +34,25 @@ all_nightly=[
     "nightly_const_params",
 ]
 
-# Enables stuff that requires const generics(in nightly Rust).
-nightly_const_params=[]
+# Enables the `#![feature(min_const_generics)]` attribute in 
+nightly_const_params=["const_params"]
 
 # Test features,only used internally.
 testing=[]
+test_const_params = []
 only_new_tests=["testing"]
 sabi_trait_examples=[]
 nonexhaustive_examples=[]
 
+# For disabling tests that break with the reduced promotion in
+# https://github.com/rust-lang/rust/pull/80243#event-4161720040
+no_fn_promotion = []
+
 channels=["crossbeam-channel"]
 
 
 [dependencies]
-abi_stable_derive= {version="0.9.0",path="../abi_stable_derive"}
+abi_stable_derive= {version="0.9.2",path="../abi_stable_derive"}
 abi_stable_shared= {version="0.9.0",path="../abi_stable_shared"}
 serde          = { version = "1.0.117", features = ["derive"] }
 repr_offset = { version = "0.1.1", default_features = false }

abi_stable/build.rs

@@ -1,17 +1,17 @@
-use rustc_version::{Version, Channel};
+use rustc_version::Channel;
 
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
     println!("cargo:rerun-if-changed=../readme.md");
 
-    let rver = rustc_version::version().unwrap();
+    let channel=rustc_version::version_meta().unwrap().channel;
+    if channel == Channel::Nightly && std::env::var("CARGO_FEATURE_test_const_params").is_ok() {
+        println!("cargo:warning=ENABLED CONST GENERICS");
 
-    if Version::new(1, 42, 0) <= rver {
-        println!("cargo:rustc-cfg=rust_1_42");
+        println!("cargo:rustc-cfg=feature=\"nightly_const_params\"");
+        println!("cargo:rustc-cfg=feature=\"const_params\"");
     }
 
-    let channel=rustc_version::version_meta().unwrap().channel;
-    if let Channel::Nightly=channel {
-        println!("cargo:rustc-cfg=feature=\"nightly_rust\"");
-    }
+
+
 }

abi_stable/src/abi_stability/const_generics.rs

@@ -48,6 +48,20 @@ impl ConstGeneric{
         }
     }
 
+    /// Constructs a ConstGeneric from an erased reference and a vtable.
+    ///
+    /// # Safety
+    ///
+    /// `this` must point to an object that lives for the `'static` lifetime,
+    /// and `vtable` must be a `ConstGenericVTableFor::<T>::NEW` 
+    /// (where `T` is the unerased type of `this`)
+    pub const unsafe fn from_erased(this: *const (), vtable: ConstGenericVTable_Ref)->Self{
+        Self{
+            ptr: this as *const ErasedObject,
+            vtable,
+        }
+    }
+
     /// Compares this to another `ConstGeneric` for equality,
     /// returning an error if the type layout of `self` and `other` is not compatible.
     pub fn is_equal(
@@ -99,12 +113,13 @@ impl Eq for ConstGeneric{}
 
 ///////////////////////////////////////////////////////////////////////////////
 
-
+/// The vtable of `ConstGeneric`,
+/// only constructible with `ConstGenericVTableFor::<T>::new.erased()`
 #[repr(C)]
 #[derive(StableAbi)]
 #[sabi(kind(Prefix))]
 #[sabi(missing_field(panic))]
-struct ConstGenericVTable{
+pub struct ConstGenericVTable {
     layout:&'static TypeLayout,
     partial_eq:unsafe extern "C" fn(&ErasedObject,&ErasedObject)->bool,
     #[sabi(last_prefix_field)]
@@ -119,9 +134,19 @@ pub struct ConstGenericVTableFor<T>{
 }
 
 
+impl<T> ConstGenericVTableFor<T> {
+    /// Allows inferring `T` by passing a reference to it.
+    pub const fn infer_type(&self, _: &T) {}
+
+    /// Extracts the vtable for the erased type.
+    pub const fn erased(&self) -> ConstGenericVTable_Ref {
+        self.vtable
+    }
+}
+
 impl<T> ConstGenericVTableFor<T> 
 where
-    T: StableAbi + Eq + PartialEq + Debug + Send + Sync
+    T: StableAbi + Eq + PartialEq + Debug + Send + Sync + 'static
 {
     const _VTABLE_STATIC: WithMetadata<ConstGenericVTable> = {
         WithMetadata::new(
@@ -140,3 +165,22 @@ where
         _marker: PhantomData,
     };
 }
+
+
+#[doc(hidden)]
+pub struct ConstGenericErasureHack<T: ?Sized>{
+    pub vtable: ConstGenericVTable_Ref,
+    pub value: T,
+}
+
+
+#[doc(hidden)]
+impl<T> ConstGenericErasureHack<T> {
+    pub const fn new(vtable: ConstGenericVTableFor<T>, value: T) -> Self {
+        Self {
+            vtable: vtable.erased(),
+            value,
+        }
+    }
+}
+