Auto merge of #54032 - oli-obk:layout_scalar_ranges, r=eddyb

Add forever unstable attribute to allow specifying arbitrary scalar ranges

r? @eddyb for the first commit and @nikomatsakis for the second one

src/libcore/nonzero.rs

@@ -14,7 +14,8 @@ use ops::CoerceUnsized;
 
 /// A wrapper type for raw pointers and integers that will never be
 /// NULL or 0 that might allow certain optimizations.
-#[lang = "non_zero"]
+#[cfg_attr(stage0, lang = "non_zero")]
+#[cfg_attr(not(stage0), rustc_layout_scalar_valid_range_start(1))]
 #[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
 #[repr(transparent)]
 pub(crate) struct NonZero<T>(pub(crate) T);

src/librustc/hir/def_id.rs

@@ -16,25 +16,53 @@ use std::fmt;
 use std::u32;
 
 newtype_index! {
-    pub struct CrateNum {
+    pub struct CrateId {
         ENCODABLE = custom
-        DEBUG_FORMAT = "crate{}",
+    }
+}
+
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash)]
+pub enum CrateNum {
+    /// Virtual crate for builtin macros
+    // FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
+    // `CrateNum`s.
+    BuiltinMacros,
+    /// A CrateNum value that indicates that something is wrong.
+    Invalid,
+    /// A special CrateNum that we use for the tcx.rcache when decoding from
+    /// the incr. comp. cache.
+    ReservedForIncrCompCache,
+    Index(CrateId),
+}
+
+impl ::std::fmt::Debug for CrateNum {
+    fn fmt(&self, fmt: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
+        match self {
+            CrateNum::Index(id) => write!(fmt, "crate{}", id.private),
+            CrateNum::Invalid => write!(fmt, "invalid crate"),
+            CrateNum::BuiltinMacros => write!(fmt, "bultin macros crate"),
+            CrateNum::ReservedForIncrCompCache => write!(fmt, "crate for decoding incr comp cache"),
+        }
+    }
+}
 
-        /// Item definitions in the currently-compiled crate would have the CrateNum
-        /// LOCAL_CRATE in their DefId.
-        const LOCAL_CRATE = 0,
+/// Item definitions in the currently-compiled crate would have the CrateNum
+/// LOCAL_CRATE in their DefId.
+pub const LOCAL_CRATE: CrateNum = CrateNum::Index(CrateId::from_u32_const(0));
 
-        /// Virtual crate for builtin macros
-        // FIXME(jseyfried): this is also used for custom derives until proc-macro crates get
-        // `CrateNum`s.
-        const BUILTIN_MACROS_CRATE = CrateNum::MAX_AS_U32,
 
-        /// A CrateNum value that indicates that something is wrong.
-        const INVALID_CRATE = CrateNum::MAX_AS_U32 - 1,
+impl Idx for CrateNum {
+    #[inline]
+    fn new(value: usize) -> Self {
+        CrateNum::Index(Idx::new(value))
+    }
 
-        /// A special CrateNum that we use for the tcx.rcache when decoding from
-        /// the incr. comp. cache.
-        const RESERVED_FOR_INCR_COMP_CACHE = CrateNum::MAX_AS_U32 - 2,
+    #[inline]
+    fn index(self) -> usize {
+        match self {
+            CrateNum::Index(idx) => Idx::index(idx),
+            _ => bug!("Tried to get crate index of {:?}", self),
+        }
     }
 }
 
@@ -43,12 +71,39 @@ impl CrateNum {
         CrateNum::from_usize(x)
     }
 
+    pub fn from_usize(x: usize) -> CrateNum {
+        CrateNum::Index(CrateId::from_usize(x))
+    }
+
+    pub fn from_u32(x: u32) -> CrateNum {
+        CrateNum::Index(CrateId::from_u32(x))
+    }
+
+    pub fn as_usize(self) -> usize {
+        match self {
+            CrateNum::Index(id) => id.as_usize(),
+            _ => bug!("tried to get index of nonstandard crate {:?}", self),
+        }
+    }
+
+    pub fn as_u32(self) -> u32 {
+        match self {
+            CrateNum::Index(id) => id.as_u32(),
+            _ => bug!("tried to get index of nonstandard crate {:?}", self),
+        }
+    }
+
     pub fn as_def_id(&self) -> DefId { DefId { krate: *self, index: CRATE_DEF_INDEX } }
 }
 
 impl fmt::Display for CrateNum {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        fmt::Display::fmt(&self.as_u32(), f)
+        match self {
+            CrateNum::Index(id) => fmt::Display::fmt(&id.private, f),
+            CrateNum::Invalid => write!(f, "invalid crate"),
+            CrateNum::BuiltinMacros => write!(f, "bultin macros crate"),
+            CrateNum::ReservedForIncrCompCache => write!(f, "crate for decoding incr comp cache"),
+        }
     }
 }
 

src/librustc/ich/impls_ty.rs

@@ -772,7 +772,15 @@ impl_stable_hash_for!(enum ty::cast::CastKind {
     FnPtrAddrCast
 });
 
-impl_stable_hash_for!(struct ::middle::region::Scope { id, code });
+impl_stable_hash_for!(struct ::middle::region::Scope { id, data });
+
+impl_stable_hash_for!(enum ::middle::region::ScopeData {
+    Node,
+    CallSite,
+    Arguments,
+    Destruction,
+    Remainder(first_statement_index)
+});
 
 impl<'a> ToStableHashKey<StableHashingContext<'a>> for region::Scope {
     type KeyType = region::Scope;
@@ -783,11 +791,6 @@ impl<'a> ToStableHashKey<StableHashingContext<'a>> for region::Scope {
     }
 }
 
-impl_stable_hash_for!(struct ::middle::region::BlockRemainder {
-    block,
-    first_statement_index
-});
-
 impl_stable_hash_for!(struct ty::adjustment::CoerceUnsizedInfo {
     custom_kind
 });

src/librustc/infer/error_reporting/mod.rs

@@ -119,17 +119,17 @@ impl<'a, 'gcx, 'tcx> TyCtxt<'a, 'gcx, 'tcx> {
                     }
                 };
                 let scope_decorated_tag = match scope.data() {
-                    region::ScopeData::Node(_) => tag,
-                    region::ScopeData::CallSite(_) => "scope of call-site for function",
-                    region::ScopeData::Arguments(_) => "scope of function body",
-                    region::ScopeData::Destruction(_) => {
+                    region::ScopeData::Node => tag,
+                    region::ScopeData::CallSite => "scope of call-site for function",
+                    region::ScopeData::Arguments => "scope of function body",
+                    region::ScopeData::Destruction => {
                         new_string = format!("destruction scope surrounding {}", tag);
                         &new_string[..]
                     }
-                    region::ScopeData::Remainder(r) => {
+                    region::ScopeData::Remainder(first_statement_index) => {
                         new_string = format!(
                             "block suffix following statement {}",
-                            r.first_statement_index.index()
+                            first_statement_index.index()
                         );
                         &new_string[..]
                     }

src/librustc/lib.rs

@@ -58,6 +58,8 @@
 #![feature(optin_builtin_traits)]
 #![feature(refcell_replace_swap)]
 #![feature(rustc_diagnostic_macros)]
+#![feature(rustc_attrs)]
+#![cfg_attr(stage0, feature(attr_literals))]
 #![feature(slice_patterns)]
 #![feature(slice_sort_by_cached_key)]
 #![feature(specialization)]

src/librustc/middle/lang_items.rs

@@ -326,8 +326,6 @@ language_item_table! {
 
     PhantomDataItem,                 "phantom_data",            phantom_data;
 
-    NonZeroItem,                     "non_zero",                non_zero;
-
     ManuallyDropItem,                "manually_drop",           manually_drop;
 
     DebugTraitLangItem,              "debug_trait",             debug_trait;