https://gcc.gnu.org/g:9819ac46419165dc59f9c5773f2d8bb878129bf6
commit r16-2804-g9819ac46419165dc59f9c5773f2d8bb878129bf6
Author: Philip Herron <herron.phi...@googlemail.com>
Date: Wed May 7 16:07:43 2025 +0100
gccrs: Prevent passing generic arguments to impl traits in argument position
When using impl traits in argument position (APIT), they are desugared into
generics,
and supplying explicit generic arguments is not allowed. This commit adds
the error
diagnostic E0632 for attempting to pass generic arguments to impl traits,
completing
the implementation of the APIT feature.
gcc/rust/ChangeLog:
* ast/rust-desugar-apit.cc: track if this is a impl-trait generic
* ast/rust-item.h (class TypeParam): add field to track if from
impl trait
* hir/rust-ast-lower-type.cc (ASTLowerGenericParam::visit): likewise
* hir/tree/rust-hir-item.cc (TypeParam::TypeParam): upate hir as
well
(TypeParam::operator=): likewise
* hir/tree/rust-hir-item.h (class TypeParam): likewise
* typecheck/rust-tyty-subst.cc
(SubstitutionParamMapping::get_generic_param): add error
* typecheck/rust-tyty-subst.h: add const getter for the associated
TypeParm
gcc/testsuite/ChangeLog:
* rust/compile/nr2/exclude: nr2 cant handle this
* rust/compile/impl_trait_generic_arg.rs: New test.
Signed-off-by: Philip Herron <herron.phi...@googlemail.com>
Diff:
---
gcc/rust/ast/rust-desugar-apit.cc | 6 ++++--
gcc/rust/ast/rust-item.h | 25 +++++++++-------------
gcc/rust/hir/rust-ast-lower-type.cc | 3 ++-
gcc/rust/hir/tree/rust-hir-item.cc | 9 +++++---
gcc/rust/hir/tree/rust-hir-item.h | 16 ++++++--------
gcc/rust/typecheck/rust-tyty-subst.cc | 21 ++++++++++++++++--
gcc/rust/typecheck/rust-tyty-subst.h | 1 +
.../rust/compile/impl_trait_generic_arg.rs | 24 +++++++++++++++++++++
gcc/testsuite/rust/compile/nr2/exclude | 1 +
9 files changed, 73 insertions(+), 33 deletions(-)
diff --git a/gcc/rust/ast/rust-desugar-apit.cc
b/gcc/rust/ast/rust-desugar-apit.cc
index 2f31bcfe7a32..5b9486ea6714 100644
--- a/gcc/rust/ast/rust-desugar-apit.cc
+++ b/gcc/rust/ast/rust-desugar-apit.cc
@@ -203,7 +203,8 @@ public:
// Create the new generic parameter
auto generic_param = std::unique_ptr<TypeParam> (
- new TypeParam (ident, type.get_locus (), std::move (bounds)));
+ new TypeParam (ident, type.get_locus (), std::move (bounds), nullptr, {},
+ true /*from impl trait*/));
// Store the generic parameter to be added to the function signature
implicit_generic_params.push_back (std::move (generic_param));
@@ -241,7 +242,8 @@ public:
// Create the new generic parameter
auto generic_param = std::unique_ptr<TypeParam> (
- new TypeParam (ident, type.get_locus (), std::move (bounds)));
+ new TypeParam (ident, type.get_locus (), std::move (bounds), nullptr, {},
+ true /*from impl trait*/));
// Store the generic parameter to be added to the function signature
implicit_generic_params.push_back (std::move (generic_param));
diff --git a/gcc/rust/ast/rust-item.h b/gcc/rust/ast/rust-item.h
index 062f85d22127..247a65f39c2e 100644
--- a/gcc/rust/ast/rust-item.h
+++ b/gcc/rust/ast/rust-item.h
@@ -51,21 +51,12 @@ class TypePath;
// A type generic parameter (as opposed to a lifetime generic parameter)
class TypeParam : public GenericParam
{
- // bool has_outer_attribute;
- // std::unique_ptr<Attribute> outer_attr;
AST::AttrVec outer_attrs;
-
Identifier type_representation;
-
- // bool has_type_param_bounds;
- // TypeParamBounds type_param_bounds;
- std::vector<std::unique_ptr<TypeParamBound>>
- type_param_bounds; // inlined form
-
- // bool has_type;
+ std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds;
std::unique_ptr<Type> type;
-
location_t locus;
+ bool was_impl_trait;
public:
Identifier get_type_representation () const { return type_representation; }
@@ -85,18 +76,19 @@ public:
std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds
= std::vector<std::unique_ptr<TypeParamBound>> (),
std::unique_ptr<Type> type = nullptr,
- AST::AttrVec outer_attrs = {})
+ AST::AttrVec outer_attrs = {}, bool was_impl_trait = false)
: GenericParam (Analysis::Mappings::get ().get_next_node_id ()),
outer_attrs (std::move (outer_attrs)),
type_representation (std::move (type_representation)),
type_param_bounds (std::move (type_param_bounds)),
- type (std::move (type)), locus (locus)
+ type (std::move (type)), locus (locus), was_impl_trait (was_impl_trait)
{}
// Copy constructor uses clone
TypeParam (TypeParam const &other)
: GenericParam (other.node_id), outer_attrs (other.outer_attrs),
- type_representation (other.type_representation), locus (other.locus)
+ type_representation (other.type_representation), locus (other.locus),
+ was_impl_trait (other.was_impl_trait)
{
// guard to prevent null pointer dereference
if (other.type != nullptr)
@@ -114,6 +106,7 @@ public:
outer_attrs = other.outer_attrs;
locus = other.locus;
node_id = other.node_id;
+ was_impl_trait = other.was_impl_trait;
// guard to prevent null pointer dereference
if (other.type != nullptr)
@@ -153,17 +146,19 @@ public:
return type;
}
- // TODO: mutable getter seems kinda dodgy
std::vector<std::unique_ptr<TypeParamBound>> &get_type_param_bounds ()
{
return type_param_bounds;
}
+
const std::vector<std::unique_ptr<TypeParamBound>> &
get_type_param_bounds () const
{
return type_param_bounds;
}
+ bool from_impl_trait () const { return was_impl_trait; }
+
protected:
// Clone function implementation as virtual method
TypeParam *clone_generic_param_impl () const override
diff --git a/gcc/rust/hir/rust-ast-lower-type.cc
b/gcc/rust/hir/rust-ast-lower-type.cc
index 4e44b1b9ce37..1841576b29f4 100644
--- a/gcc/rust/hir/rust-ast-lower-type.cc
+++ b/gcc/rust/hir/rust-ast-lower-type.cc
@@ -620,7 +620,8 @@ ASTLowerGenericParam::visit (AST::TypeParam ¶m)
translated
= new HIR::TypeParam (mapping, param.get_type_representation (),
param.get_locus (), std::move (type_param_bounds),
- std::move (type), param.get_outer_attrs ());
+ std::move (type), param.get_outer_attrs (),
+ param.from_impl_trait ());
}
HIR::TypeParamBound *
diff --git a/gcc/rust/hir/tree/rust-hir-item.cc
b/gcc/rust/hir/tree/rust-hir-item.cc
index 160f710408af..1406e7aeb515 100644
--- a/gcc/rust/hir/tree/rust-hir-item.cc
+++ b/gcc/rust/hir/tree/rust-hir-item.cc
@@ -26,16 +26,18 @@ TypeParam::TypeParam (
Analysis::NodeMapping mappings, Identifier type_representation,
location_t locus,
std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds,
- tl::optional<std::unique_ptr<Type>> type, AST::AttrVec outer_attrs)
+ tl::optional<std::unique_ptr<Type>> type, AST::AttrVec outer_attrs,
+ bool was_impl_trait)
: GenericParam (mappings), outer_attrs (std::move (outer_attrs)),
type_representation (std::move (type_representation)),
type_param_bounds (std::move (type_param_bounds)), type (std::move (type)),
- locus (locus)
+ locus (locus), was_impl_trait (was_impl_trait)
{}
TypeParam::TypeParam (TypeParam const &other)
: GenericParam (other.mappings), outer_attrs (other.outer_attrs),
- type_representation (other.type_representation), locus (other.locus)
+ type_representation (other.type_representation), locus (other.locus),
+ was_impl_trait (other.was_impl_trait)
{
// guard to prevent null pointer dereference
if (other.has_type ())
@@ -55,6 +57,7 @@ TypeParam::operator= (TypeParam const &other)
outer_attrs = other.outer_attrs;
locus = other.locus;
mappings = other.mappings;
+ was_impl_trait = other.was_impl_trait;
// guard to prevent null pointer dereference
if (other.has_type ())
diff --git a/gcc/rust/hir/tree/rust-hir-item.h
b/gcc/rust/hir/tree/rust-hir-item.h
index 37f599cdee4a..d61027732ab9 100644
--- a/gcc/rust/hir/tree/rust-hir-item.h
+++ b/gcc/rust/hir/tree/rust-hir-item.h
@@ -95,17 +95,11 @@ protected:
class TypeParam : public GenericParam
{
AST::AttrVec outer_attrs;
-
Identifier type_representation;
-
- // bool has_type_param_bounds;
- // TypeParamBounds type_param_bounds;
- std::vector<std::unique_ptr<TypeParamBound>>
- type_param_bounds; // inlined form
-
+ std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds;
tl::optional<std::unique_ptr<Type>> type;
-
location_t locus;
+ bool was_impl_trait;
public:
// Returns whether the type of the type param has been specified.
@@ -121,9 +115,9 @@ public:
TypeParam (Analysis::NodeMapping mappings, Identifier type_representation,
location_t locus = UNDEF_LOCATION,
std::vector<std::unique_ptr<TypeParamBound>> type_param_bounds
- = std::vector<std::unique_ptr<TypeParamBound>> (),
+ = {},
tl::optional<std::unique_ptr<Type>> type = tl::nullopt,
- AST::AttrVec outer_attrs = std::vector<AST::Attribute> ());
+ AST::AttrVec outer_attrs = {}, bool was_impl_trait = false);
// Copy constructor uses clone
TypeParam (TypeParam const &other);
@@ -154,6 +148,8 @@ public:
std::vector<std::unique_ptr<TypeParamBound>> &get_type_param_bounds ();
+ bool from_impl_trait () const { return was_impl_trait; }
+
protected:
// Clone function implementation as (not pure) virtual method
TypeParam *clone_generic_param_impl () const override
diff --git a/gcc/rust/typecheck/rust-tyty-subst.cc
b/gcc/rust/typecheck/rust-tyty-subst.cc
index bdb6474aeeb4..28d311a8aad2 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.cc
+++ b/gcc/rust/typecheck/rust-tyty-subst.cc
@@ -72,6 +72,12 @@ SubstitutionParamMapping::get_generic_param ()
return generic;
}
+const HIR::TypeParam &
+SubstitutionParamMapping::get_generic_param () const
+{
+ return generic;
+}
+
bool
SubstitutionParamMapping::needs_substitution () const
{
@@ -618,7 +624,6 @@ SubstitutionRef::get_mappings_from_generic_args (
if (args.get_binding_args ().size () > get_num_associated_bindings ())
{
rich_location r (line_table, args.get_locus ());
-
rust_error_at (r,
"generic item takes at most %lu type binding "
"arguments but %lu were supplied",
@@ -702,7 +707,19 @@ SubstitutionRef::get_mappings_from_generic_args (
return SubstitutionArgumentMappings::error ();
}
- SubstitutionArg subst_arg (&substitutions.at (offs), resolved);
+ const auto ¶m_mapping = substitutions.at (offs);
+ const auto &type_param = param_mapping.get_generic_param ();
+ if (type_param.from_impl_trait ())
+ {
+ rich_location r (line_table, arg->get_locus ());
+ r.add_fixit_remove (arg->get_locus ());
+ rust_error_at (r, ErrorCode::E0632,
+ "cannot provide explicit generic arguments when "
+ "%<impl Trait%> is used in argument position");
+ return SubstitutionArgumentMappings::error ();
+ }
+
+ SubstitutionArg subst_arg (¶m_mapping, resolved);
offs++;
mappings.push_back (std::move (subst_arg));
}
diff --git a/gcc/rust/typecheck/rust-tyty-subst.h
b/gcc/rust/typecheck/rust-tyty-subst.h
index e6ed1fc42d67..2f5de23aa00f 100644
--- a/gcc/rust/typecheck/rust-tyty-subst.h
+++ b/gcc/rust/typecheck/rust-tyty-subst.h
@@ -60,6 +60,7 @@ public:
const ParamType *get_param_ty () const;
HIR::TypeParam &get_generic_param ();
+ const HIR::TypeParam &get_generic_param () const;
// this is used for the backend to override the HirId ref of the param to
// what the concrete type is for the rest of the context
diff --git a/gcc/testsuite/rust/compile/impl_trait_generic_arg.rs
b/gcc/testsuite/rust/compile/impl_trait_generic_arg.rs
new file mode 100644
index 000000000000..ecdb08803b40
--- /dev/null
+++ b/gcc/testsuite/rust/compile/impl_trait_generic_arg.rs
@@ -0,0 +1,24 @@
+#[lang = "sized"]
+trait Sized {}
+
+trait Foo {
+ fn id(&self) -> u8;
+}
+
+struct Bar;
+
+impl Foo for Bar {
+ fn id(&self) -> u8 {
+ 1
+ }
+}
+
+fn takes(val: impl Foo) -> u8 {
+ val.id()
+}
+
+fn main() {
+ let b = Bar;
+ let x = takes::<Bar>(b);
+ // { dg-error "cannot provide explicit generic arguments when .impl Trait.
is used in argument position .E0632." "" { target *-*-* } .-1 }
+}
diff --git a/gcc/testsuite/rust/compile/nr2/exclude
b/gcc/testsuite/rust/compile/nr2/exclude
index d3bdb1cce0df..b9b9e39aa82c 100644
--- a/gcc/testsuite/rust/compile/nr2/exclude
+++ b/gcc/testsuite/rust/compile/nr2/exclude
@@ -17,4 +17,5 @@ issue-3649.rs
issue-1487.rs
issue-2015.rs
issue-3454.rs
+impl_trait_generic_arg.rs
# please don't delete the trailing newline
