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Auto merge of #54821 - pietroalbini:beta-backports, r=pietroalbini
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[beta] Rollup backports

Merged and approved:

* #54605: resolve: Disambiguate a subset of conflicts "macro_rules" vs "macro name in module"
* #54557: incr.comp.: Don't automatically enable -Zshare-generics for incr. comp. builds.
* #54759: do not normalize non-scalar constants to a ConstValue::ScalarPair

Closes #54759
r? @ghost
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bors committed Oct 4, 2018
2 parents f11dae2 + e3f6931 commit 96a2298
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Showing 12 changed files with 160 additions and 30 deletions.
1 change: 0 additions & 1 deletion src/librustc/session/config.rs
Original file line number Diff line number Diff line change
Expand Up @@ -646,7 +646,6 @@ impl Options {
match self.debugging_opts.share_generics {
Some(setting) => setting,
None => {
self.incremental.is_some() ||
match self.optimize {
OptLevel::No |
OptLevel::Less |
Expand Down
14 changes: 12 additions & 2 deletions src/librustc_mir/const_eval.rs
Original file line number Diff line number Diff line change
Expand Up @@ -17,7 +17,7 @@ use rustc::hir::{self, def_id::DefId};
use rustc::mir::interpret::ConstEvalErr;
use rustc::mir;
use rustc::ty::{self, TyCtxt, Instance, query::TyCtxtAt};
use rustc::ty::layout::{LayoutOf, TyLayout};
use rustc::ty::layout::{self, LayoutOf, TyLayout};
use rustc::ty::subst::Subst;
use rustc_data_structures::indexed_vec::IndexVec;

Expand Down Expand Up @@ -90,8 +90,18 @@ pub fn eval_promoted<'a, 'mir, 'tcx>(
pub fn op_to_const<'tcx>(
ecx: &EvalContext<'_, '_, 'tcx, CompileTimeEvaluator>,
op: OpTy<'tcx>,
normalize: bool,
may_normalize: bool,
) -> EvalResult<'tcx, &'tcx ty::Const<'tcx>> {
// We do not normalize just any data. Only scalar layout and fat pointers.
let normalize = may_normalize
&& match op.layout.abi {
layout::Abi::Scalar(..) => true,
layout::Abi::ScalarPair(..) => {
// Must be a fat pointer
op.layout.ty.builtin_deref(true).is_some()
},
_ => false,
};
let normalized_op = if normalize {
ecx.try_read_value(op)?
} else {
Expand Down
43 changes: 40 additions & 3 deletions src/librustc_resolve/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -71,11 +71,10 @@ use syntax_pos::{Span, DUMMY_SP, MultiSpan};
use errors::{Applicability, DiagnosticBuilder, DiagnosticId};

use std::cell::{Cell, RefCell};
use std::cmp;
use std::{cmp, fmt, iter, ptr};
use std::collections::BTreeSet;
use std::fmt;
use std::iter;
use std::mem::replace;
use rustc_data_structures::ptr_key::PtrKey;
use rustc_data_structures::sync::Lrc;

use resolve_imports::{ImportDirective, ImportDirectiveSubclass, NameResolution, ImportResolver};
Expand Down Expand Up @@ -1113,6 +1112,17 @@ impl<'a> ModuleData<'a> {
fn nearest_item_scope(&'a self) -> Module<'a> {
if self.is_trait() { self.parent.unwrap() } else { self }
}

fn is_ancestor_of(&self, mut other: &Self) -> bool {
while !ptr::eq(self, other) {
if let Some(parent) = other.parent {
other = parent;
} else {
return false;
}
}
true
}
}

impl<'a> fmt::Debug for ModuleData<'a> {
Expand Down Expand Up @@ -1407,6 +1417,7 @@ pub struct Resolver<'a, 'b: 'a> {
block_map: NodeMap<Module<'a>>,
module_map: FxHashMap<DefId, Module<'a>>,
extern_module_map: FxHashMap<(DefId, bool /* MacrosOnly? */), Module<'a>>,
binding_parent_modules: FxHashMap<PtrKey<'a, NameBinding<'a>>, Module<'a>>,

pub make_glob_map: bool,
/// Maps imports to the names of items actually imported (this actually maps
Expand Down Expand Up @@ -1709,6 +1720,7 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
module_map,
block_map: NodeMap(),
extern_module_map: FxHashMap(),
binding_parent_modules: FxHashMap(),

make_glob_map: make_glob_map == MakeGlobMap::Yes,
glob_map: NodeMap(),
Expand Down Expand Up @@ -4526,6 +4538,31 @@ impl<'a, 'crateloader: 'a> Resolver<'a, 'crateloader> {
vis.is_accessible_from(module.normal_ancestor_id, self)
}

fn set_binding_parent_module(&mut self, binding: &'a NameBinding<'a>, module: Module<'a>) {
if let Some(old_module) = self.binding_parent_modules.insert(PtrKey(binding), module) {
if !ptr::eq(module, old_module) {
span_bug!(binding.span, "parent module is reset for binding");
}
}
}

fn disambiguate_legacy_vs_modern(
&self,
legacy: &'a NameBinding<'a>,
modern: &'a NameBinding<'a>,
) -> bool {
// Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
// is disambiguated to mitigate regressions from macro modularization.
// Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.
match (self.binding_parent_modules.get(&PtrKey(legacy)),
self.binding_parent_modules.get(&PtrKey(modern))) {
(Some(legacy), Some(modern)) =>
legacy.normal_ancestor_id == modern.normal_ancestor_id &&
modern.is_ancestor_of(legacy),
_ => false,
}
}

fn report_ambiguity_error(&self, ident: Ident, b1: &NameBinding, b2: &NameBinding) {
let participle = |is_import: bool| if is_import { "imported" } else { "defined" };
let msg1 =
Expand Down
5 changes: 4 additions & 1 deletion src/librustc_resolve/macros.rs
Original file line number Diff line number Diff line change
Expand Up @@ -956,11 +956,13 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
},
(Some(legacy_binding), Ok((binding, FromPrelude(from_prelude))))
if legacy_binding.def() != binding.def_ignoring_ambiguity() &&
(!from_prelude ||
(!from_prelude &&
!self.disambiguate_legacy_vs_modern(legacy_binding, binding) ||
legacy_binding.may_appear_after(parent_scope.expansion, binding)) => {
self.report_ambiguity_error(ident, legacy_binding, binding);
},
// OK, non-macro-expanded legacy wins over prelude even if defs are different
// Also, non-macro-expanded legacy wins over modern from the same module
// Also, legacy and modern can co-exist if their defs are same
(Some(legacy_binding), Ok(_)) |
// OK, unambiguous resolution
Expand Down Expand Up @@ -1096,6 +1098,7 @@ impl<'a, 'cl> Resolver<'a, 'cl> {
let def = Def::Macro(def_id, MacroKind::Bang);
let vis = ty::Visibility::Invisible; // Doesn't matter for legacy bindings
let binding = (def, vis, item.span, expansion).to_name_binding(self.arenas);
self.set_binding_parent_module(binding, self.current_module);
let legacy_binding = self.arenas.alloc_legacy_binding(LegacyBinding {
parent_legacy_scope: *current_legacy_scope, binding, ident
});
Expand Down
1 change: 1 addition & 0 deletions src/librustc_resolve/resolve_imports.rs
Original file line number Diff line number Diff line change
Expand Up @@ -478,6 +478,7 @@ impl<'a, 'crateloader> Resolver<'a, 'crateloader> {
binding: &'a NameBinding<'a>)
-> Result<(), &'a NameBinding<'a>> {
self.check_reserved_macro_name(ident, ns);
self.set_binding_parent_module(binding, module);
self.update_resolution(module, ident, ns, |this, resolution| {
if let Some(old_binding) = resolution.binding {
if binding.is_glob_import() {
Expand Down
2 changes: 1 addition & 1 deletion src/test/ui/consts/const-eval/union-ice.rs
Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,7 @@ const UNION: DummyUnion = DummyUnion { field1: 1065353216 };

const FIELD3: Field3 = unsafe { UNION.field3 }; //~ ERROR this constant cannot be used

const FIELD_PATH: Struct = Struct { //~ ERROR this constant cannot be used
const FIELD_PATH: Struct = Struct { //~ ERROR this constant likely exhibits undefined behavior
a: 42,
b: unsafe { UNION.field3 },
};
Expand Down
8 changes: 5 additions & 3 deletions src/test/ui/consts/const-eval/union-ice.stderr
Original file line number Diff line number Diff line change
Expand Up @@ -6,14 +6,16 @@ LL | const FIELD3: Field3 = unsafe { UNION.field3 }; //~ ERROR this constant can
|
= note: #[deny(const_err)] on by default

error: this constant cannot be used
error[E0080]: this constant likely exhibits undefined behavior
--> $DIR/union-ice.rs:25:1
|
LL | / const FIELD_PATH: Struct = Struct { //~ ERROR this constant cannot be used
LL | / const FIELD_PATH: Struct = Struct { //~ ERROR this constant likely exhibits undefined behavior
LL | | a: 42,
LL | | b: unsafe { UNION.field3 },
LL | | };
| |__^ attempted to read undefined bytes
| |__^ type validation failed: encountered undefined bytes at .b
|
= note: The rules on what exactly is undefined behavior aren't clear, so this check might be overzealous. Please open an issue on the rust compiler repository if you believe it should not be considered undefined behavior

error[E0080]: this constant likely exhibits undefined behavior
--> $DIR/union-ice.rs:35:1
Expand Down
2 changes: 1 addition & 1 deletion src/test/ui/imports/macros.rs
Original file line number Diff line number Diff line change
Expand Up @@ -45,7 +45,7 @@ mod m3 {
mod m4 {
macro_rules! m { () => {} }
use two_macros::m;
m!(); //~ ERROR ambiguous
m!();
}

fn main() {}
19 changes: 1 addition & 18 deletions src/test/ui/imports/macros.stderr
Original file line number Diff line number Diff line change
@@ -1,20 +1,3 @@
error[E0659]: `m` is ambiguous
--> $DIR/macros.rs:48:5
|
LL | m!(); //~ ERROR ambiguous
| ^ ambiguous name
|
note: `m` could refer to the name defined here
--> $DIR/macros.rs:46:5
|
LL | macro_rules! m { () => {} }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: `m` could also refer to the name imported here
--> $DIR/macros.rs:47:9
|
LL | use two_macros::m;
| ^^^^^^^^^^^^^

error[E0659]: `m` is ambiguous
--> $DIR/macros.rs:26:5
|
Expand Down Expand Up @@ -51,6 +34,6 @@ LL | use two_macros::m;
| ^^^^^^^^^^^^^
= note: macro-expanded macro imports do not shadow

error: aborting due to 3 previous errors
error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0659`.
12 changes: 12 additions & 0 deletions src/test/ui/issues/issue-54387.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,12 @@
// compile-pass

pub struct GstRc {
_obj: *const (),
_borrowed: bool,
}

const FOO: Option<GstRc> = None;

fn main() {
let _meh = FOO;
}
46 changes: 46 additions & 0 deletions src/test/ui/macros/ambiguity-legacy-vs-modern.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,46 @@
// Some non-controversial subset of ambiguities "modern macro name" vs "macro_rules"
// is disambiguated to mitigate regressions from macro modularization.
// Scoping for `macro_rules` behaves like scoping for `let` at module level, in general.

#![feature(decl_macro)]

fn same_unnamed_mod() {
macro m() { 0 }

macro_rules! m { () => (()) }

m!() // OK
}

fn nested_unnamed_mod() {
macro m() { 0 }

{
macro_rules! m { () => (()) }

m!() // OK
}
}

fn nested_unnamed_mod_fail() {
macro_rules! m { () => (()) }

{
macro m() { 0 }

m!() //~ ERROR `m` is ambiguous
}
}

fn nexted_named_mod_fail() {
macro m() { 0 }

#[macro_use]
mod inner {
macro_rules! m { () => (()) }
}

m!() //~ ERROR `m` is ambiguous
}

fn main() {}
37 changes: 37 additions & 0 deletions src/test/ui/macros/ambiguity-legacy-vs-modern.stderr
Original file line number Diff line number Diff line change
@@ -0,0 +1,37 @@
error[E0659]: `m` is ambiguous
--> $DIR/ambiguity-legacy-vs-modern.rs:31:9
|
LL | m!() //~ ERROR `m` is ambiguous
| ^ ambiguous name
|
note: `m` could refer to the name defined here
--> $DIR/ambiguity-legacy-vs-modern.rs:26:5
|
LL | macro_rules! m { () => (()) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: `m` could also refer to the name defined here
--> $DIR/ambiguity-legacy-vs-modern.rs:29:9
|
LL | macro m() { 0 }
| ^^^^^^^^^^^^^^^

error[E0659]: `m` is ambiguous
--> $DIR/ambiguity-legacy-vs-modern.rs:43:5
|
LL | m!() //~ ERROR `m` is ambiguous
| ^ ambiguous name
|
note: `m` could refer to the name defined here
--> $DIR/ambiguity-legacy-vs-modern.rs:40:9
|
LL | macro_rules! m { () => (()) }
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
note: `m` could also refer to the name defined here
--> $DIR/ambiguity-legacy-vs-modern.rs:36:5
|
LL | macro m() { 0 }
| ^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0659`.

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