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* [gcc/devel/rust/master] Fix bad inherent overlap error
@ 2022-06-08 12:27 Thomas Schwinge
0 siblings, 0 replies; only message in thread
From: Thomas Schwinge @ 2022-06-08 12:27 UTC (permalink / raw)
To: gcc-cvs
https://gcc.gnu.org/g:4413bc0cf8b98702e8dd9e88ab5c0e19903e58e7
commit 4413bc0cf8b98702e8dd9e88ab5c0e19903e58e7
Author: Philip Herron <philip.herron@embecosm.com>
Date: Wed Mar 30 18:13:48 2022 +0100
Fix bad inherent overlap error
When we examine HIR::ImplBlock's we determine if an impl might overlap
another impl based on the Self type. So for example you might have a
generic structure Foo<T>(T), and an associated impl block for Foo<i32>, but
then go on to define an associated impl of Foo<T> the generic one will
overlap any associated impl hiding the generic implementation.
In this case we have two generic impl blocks
*const [T]
*const T
This means the *const T might overlap with the slice one since it is
generic. As bjorn3 pointed out in #1075, the correct implementation is to
observe that [T] is constrained by size but untill we have the auto trait
of Sized we must example the two generic impls and just determine that
they are not-equal so for now this is the best implementation we can do.
Fixes #1075
Diff:
---
.../typecheck/rust-hir-inherent-impl-overlap.h | 25 +++++++++++--
gcc/rust/typecheck/rust-hir-path-probe.h | 5 ++-
gcc/rust/typecheck/rust-tyty-bounds.cc | 5 ++-
gcc/rust/typecheck/rust-tyty-cmp.h | 26 --------------
gcc/testsuite/rust/compile/generics7.rs | 2 +-
gcc/testsuite/rust/compile/generics8.rs | 2 +-
gcc/testsuite/rust/compile/torture/issue-1075.rs | 42 ++++++++++++++++++++++
7 files changed, 74 insertions(+), 33 deletions(-)
diff --git a/gcc/rust/typecheck/rust-hir-inherent-impl-overlap.h b/gcc/rust/typecheck/rust-hir-inherent-impl-overlap.h
index 2908a4b5121..9abf87280ad 100644
--- a/gcc/rust/typecheck/rust-hir-inherent-impl-overlap.h
+++ b/gcc/rust/typecheck/rust-hir-inherent-impl-overlap.h
@@ -123,7 +123,26 @@ public:
continue;
if (query->can_eq (candidate, false))
- possible_collision (it->second, iy->second);
+ {
+ // we might be in the case that we have:
+ //
+ // *const T vs *const [T]
+ //
+ // so lets use an equality check when the
+ // candidates are both generic to be sure we dont emit a false
+ // positive
+
+ bool a = query->is_concrete ();
+ bool b = candidate->is_concrete ();
+ bool both_generic = !a && !b;
+ if (both_generic)
+ {
+ if (!query->is_equal (*candidate))
+ continue;
+ }
+
+ possible_collision (it->second, iy->second);
+ }
}
}
}
@@ -152,8 +171,8 @@ public:
void collision_detected (HIR::ImplItem *query, HIR::ImplItem *dup,
const std::string &name)
{
- RichLocation r (query->get_locus ());
- r.add_range (dup->get_locus ());
+ RichLocation r (dup->get_locus ());
+ r.add_range (query->get_locus ());
rust_error_at (r, "duplicate definitions with name %s", name.c_str ());
}
diff --git a/gcc/rust/typecheck/rust-hir-path-probe.h b/gcc/rust/typecheck/rust-hir-path-probe.h
index 3c1858cf554..fda505aa84e 100644
--- a/gcc/rust/typecheck/rust-hir-path-probe.h
+++ b/gcc/rust/typecheck/rust-hir-path-probe.h
@@ -284,7 +284,10 @@ protected:
return;
if (!receiver->can_eq (impl_block_ty, false))
- return;
+ {
+ if (!impl_block_ty->can_eq (receiver, false))
+ return;
+ }
// lets visit the impl_item
item->accept_vis (*this);
diff --git a/gcc/rust/typecheck/rust-tyty-bounds.cc b/gcc/rust/typecheck/rust-tyty-bounds.cc
index a7ec42c7a1c..b34db3bd44e 100644
--- a/gcc/rust/typecheck/rust-tyty-bounds.cc
+++ b/gcc/rust/typecheck/rust-tyty-bounds.cc
@@ -41,7 +41,10 @@ TypeBoundsProbe::scan ()
return true;
if (!receiver->can_eq (impl_type, false))
- return true;
+ {
+ if (!impl_type->can_eq (receiver, false))
+ return true;
+ }
possible_trait_paths.push_back ({impl->get_trait_ref ().get (), impl});
return true;
diff --git a/gcc/rust/typecheck/rust-tyty-cmp.h b/gcc/rust/typecheck/rust-tyty-cmp.h
index afc928da110..34c89639f6f 100644
--- a/gcc/rust/typecheck/rust-tyty-cmp.h
+++ b/gcc/rust/typecheck/rust-tyty-cmp.h
@@ -886,8 +886,6 @@ public:
ok = true;
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const ArrayType *base;
@@ -916,8 +914,6 @@ public:
ok = true;
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const SliceType *base;
@@ -939,8 +935,6 @@ public:
ok = type.get_infer_kind () == InferType::InferTypeKind::GENERAL;
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const BoolType *base;
@@ -965,8 +959,6 @@ public:
ok = type.get_int_kind () == base->get_int_kind ();
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const IntType *base;
@@ -991,8 +983,6 @@ public:
ok = type.get_uint_kind () == base->get_uint_kind ();
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const UintType *base;
@@ -1017,8 +1007,6 @@ public:
ok = type.get_float_kind () == base->get_float_kind ();
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const FloatType *base;
@@ -1120,8 +1108,6 @@ public:
ok = true;
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const TupleType *base;
@@ -1143,8 +1129,6 @@ public:
void visit (const USizeType &type) override { ok = true; }
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const USizeType *base;
@@ -1166,8 +1150,6 @@ public:
void visit (const ISizeType &type) override { ok = true; }
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const ISizeType *base;
@@ -1189,8 +1171,6 @@ public:
void visit (const CharType &type) override { ok = true; }
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const CharType *base;
@@ -1365,8 +1345,6 @@ public:
void visit (const StrType &type) override { ok = true; }
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const StrType *base;
@@ -1383,8 +1361,6 @@ public:
void visit (const NeverType &type) override { ok = true; }
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
const NeverType *base;
@@ -1478,8 +1454,6 @@ public:
ok = base->bounds_compatible (type, ref_locus, false);
}
- void visit (const ParamType &type) override { ok = true; }
-
private:
const BaseType *get_base () const override { return base; }
diff --git a/gcc/testsuite/rust/compile/generics7.rs b/gcc/testsuite/rust/compile/generics7.rs
index 78b6149437c..2a41632e693 100644
--- a/gcc/testsuite/rust/compile/generics7.rs
+++ b/gcc/testsuite/rust/compile/generics7.rs
@@ -15,7 +15,7 @@ impl Foo<char> {
}
impl<T> Foo<T> {
- fn bar(self) -> T { // { dg-error "duplicate definitions with name bar" }
+ fn bar(self) -> T {
self.a
}
}
diff --git a/gcc/testsuite/rust/compile/generics8.rs b/gcc/testsuite/rust/compile/generics8.rs
index 70bad1a4c1c..ceefc5d2c6a 100644
--- a/gcc/testsuite/rust/compile/generics8.rs
+++ b/gcc/testsuite/rust/compile/generics8.rs
@@ -1,7 +1,7 @@
struct Foo<A, B>(A, B);
impl<T> Foo<i32, T> {
- fn test(a: T) -> T { // { dg-error "duplicate definitions with name test" }
+ fn test(a: T) -> T {
a
}
}
diff --git a/gcc/testsuite/rust/compile/torture/issue-1075.rs b/gcc/testsuite/rust/compile/torture/issue-1075.rs
new file mode 100644
index 00000000000..3bd6321a940
--- /dev/null
+++ b/gcc/testsuite/rust/compile/torture/issue-1075.rs
@@ -0,0 +1,42 @@
+// { dg-additional-options "-w" }
+extern "rust-intrinsic" {
+ pub fn offset<T>(dst: *const T, offset: isize) -> *const T;
+}
+
+struct FatPtr<T> {
+ data: *const T,
+ len: usize,
+}
+
+union Repr<T> {
+ rust: *const [T],
+ rust_mut: *mut [T],
+ raw: FatPtr<T>,
+}
+
+impl<T> *const [T] {
+ pub const fn len(self) -> usize {
+ // SAFETY: this is safe because `*const [T]` and `FatPtr<T>` have the same layout.
+ // Only `std` can make this guarantee.
+ let a = unsafe { Repr { rust: self }.raw };
+ a.len
+ }
+
+ pub const fn as_ptr(self) -> *const T {
+ self as *const T
+ }
+}
+
+impl<T> *const T {
+ pub const unsafe fn offset(self, count: isize) -> *const T {
+ unsafe { offset(self, count) }
+ }
+
+ pub const unsafe fn add(self, count: usize) -> Self {
+ unsafe { self.offset(count as isize) }
+ }
+
+ pub const fn as_ptr(self) -> *const T {
+ self as *const T
+ }
+}
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