[gccrs COMMIT] gccrs: Add missing bounds checks on the associated impl
gerris.rs@gmail.com
gerris.rs@gmail.com
Sun Aug 16 22:55:56 GMT 2026
From: Philip Herron <herron.philip@googlemail.com>
Before this require_b<T: B> (T) only checked for S<Bad> implement B and
it early accepted the
impl<T: A> B for S<T>
But we need to validate the impl's bound after we bind the arguments being
used on the generic impl. So when we do a call-expr/method-call expr we are
binding to that impl and we need to validate. When we do that we know that
impl T = Bad and we walk the impl generic params T: A apply the subst for
Bad: A where its is not implemented and we fail and return.
Fixes Rust-GCC/gccrs#4678
gcc/rust/ChangeLog:
* typecheck/rust-hir-trait-reference.h: add emit_errors option
* typecheck/rust-hir-trait-resolve.cc (AssociatedImplTrait::bind_impl_for_projection): new
(AssociatedImplTrait::bind_impl_for_bound): call new validate function
* typecheck/rust-type-util.cc (lookup_associated_impl_block): make this more generic
* typecheck/rust-tyty-call.cc (validate_call_argument_associated_impl_bounds): new
(TypeCheckCallExpr::visit): for each call arg validate and bind
(TypeCheckMethodCallExpr::check): likewise
gcc/testsuite/ChangeLog:
* rust/compile/issue-4678.rs: New test.
Signed-off-by: Philip Herron <herron.philip@googlemail.com>
---
This change was merged into the gccrs repository and is posted here for
upstream visibility and potential drive-by review, as requested by GCC
release managers.
Each commit email contains a link to its details on github from where you can
find the Pull-Request and associated discussions.
Commit on github: https://github.com/Rust-GCC/gccrs/commit/fde042ef7c7241b40e12b3dabaea90d4298c6fa5
The commit has been mentioned in the following issue(s):
- Rust-GCC/gccrs#4678: https://github.com/Rust-GCC/gccrs/issues/4678
The commit has been mentioned in the following pull-request(s):
- https://github.com/Rust-GCC/gccrs/pull/4787
gcc/rust/typecheck/rust-hir-trait-reference.h | 3 +-
gcc/rust/typecheck/rust-hir-trait-resolve.cc | 93 ++++++++++++++++++-
gcc/rust/typecheck/rust-type-util.cc | 2 +-
gcc/rust/typecheck/rust-tyty-call.cc | 46 +++++++++
gcc/testsuite/rust/compile/issue-4678.rs | 23 +++++
5 files changed, 164 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/rust/compile/issue-4678.rs
diff --git a/gcc/rust/typecheck/rust-hir-trait-reference.h b/gcc/rust/typecheck/rust-hir-trait-reference.h
index a8f923826..b26ba0ad5 100644
--- a/gcc/rust/typecheck/rust-hir-trait-reference.h
+++ b/gcc/rust/typecheck/rust-hir-trait-reference.h
@@ -253,7 +253,8 @@ public:
TyTy::SubstitutionArgumentMappings
bind_impl_for_bound (TyTy::BaseType *receiver,
- const TyTy::TypeBoundPredicate &bound, location_t locus);
+ const TyTy::TypeBoundPredicate &bound, location_t locus,
+ bool emit_error = false);
private:
TraitReference *trait;
diff --git a/gcc/rust/typecheck/rust-hir-trait-resolve.cc b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
index b036c634f..3ed46e0f0 100644
--- a/gcc/rust/typecheck/rust-hir-trait-resolve.cc
+++ b/gcc/rust/typecheck/rust-hir-trait-resolve.cc
@@ -17,16 +17,100 @@
// <http://www.gnu.org/licenses/>.
#include "rust-hir-trait-resolve.h"
+#include "rich-location.h"
#include "rust-hir-trait-reference.h"
#include "rust-hir-type-check-expr.h"
#include "rust-rib.h"
#include "rust-substitution-mapper.h"
+#include "text-range-label.h"
#include "rust-type-util.h"
#include "rust-finalized-name-resolution-context.h"
namespace Rust {
namespace Resolver {
+static bool
+validate_impl_substitution_bounds (
+ const std::vector<TyTy::SubstitutionArg> &resolved_args, location_t locus,
+ bool emit_error)
+{
+ auto &mctx = Analysis::Mappings::get ();
+
+ std::vector<TyTy::SubstitutionArg> args;
+ for (const auto &arg : resolved_args)
+ args.push_back (arg);
+
+ TyTy::SubstitutionArgumentMappings mappings (std::move (args),
+ {} /*binding_args*/,
+ TyTy::RegionParamList (0),
+ locus);
+
+ for (const auto &arg : resolved_args)
+ {
+ TyTy::BaseGeneric *param
+ = const_cast<TyTy::BaseGeneric *> (arg.get_param_ty ());
+ if (param == nullptr)
+ continue;
+
+ TyTy::BaseType *resolved_arg = arg.get_tyty ();
+ if (resolved_arg->get_kind () == TyTy::TypeKind::PARAM)
+ resolved_arg
+ = static_cast<TyTy::ParamType *> (resolved_arg)->resolve ();
+
+ if (resolved_arg->get_kind () == TyTy::TypeKind::PARAM
+ || resolved_arg->get_kind () == TyTy::TypeKind::INFER)
+ continue;
+
+ auto arg_type_locus
+ = mctx.lookup_location (arg.get_tyty ()->get_ty_ref ());
+ for (auto bound : param->get_specified_bounds ())
+ {
+ auto bound_locus = bound.get_locus ();
+ auto trait_locus = bound.get ()->get_locus ();
+ bound.apply_argument_mappings (mappings, false /*is_super_trait*/);
+
+ if (!resolved_arg->satisfies_bound (bound, false /*emit_error*/))
+ {
+ if (emit_error)
+ {
+ rich_location r (line_table, locus);
+
+ std::string arg_label_text = "the trait " + bound.get_name ()
+ + " is not implemented for "
+ + resolved_arg->get_name ();
+
+ text_range_label arg_label (arg_label_text.c_str ());
+ r.add_range (arg_type_locus, SHOW_RANGE_WITHOUT_CARET,
+ &arg_label);
+
+ bool ambiguous = false;
+ auto *trait_impl
+ = lookup_associated_impl_block (bound, resolved_arg,
+ &ambiguous);
+ text_range_label trait_label (
+ "this trait has no implementations, consider adding one");
+ if (trait_impl == nullptr)
+ r.add_range (trait_locus, SHOW_RANGE_WITHOUT_CARET,
+ &trait_label);
+
+ text_range_label bound_label (
+ "unsatisfied trait bound introduced here");
+ r.add_range (bound_locus, SHOW_RANGE_WITHOUT_CARET,
+ &bound_label);
+
+ rust_error_at (r, ErrorCode::E0277,
+ "the trait bound %<%s: %s%> is not satisfied",
+ resolved_arg->get_name ().c_str (),
+ bound.get_name ().c_str ());
+ }
+ return false;
+ }
+ }
+ }
+
+ return true;
+}
+
TraitItemReference
ResolveTraitItemToRef::Resolve (
HIR::TraitItem &item, TyTy::BaseType *self,
@@ -598,6 +682,10 @@ AssociatedImplTrait::bind_impl_for_projection (TyTy::ProjectionType &proj,
resolved_args.emplace_back (&p, r);
}
+ if (!validate_impl_substitution_bounds (resolved_args, locus,
+ false /*emit_error*/))
+ return TyTy::SubstitutionArgumentMappings::error ();
+
return TyTy::SubstitutionArgumentMappings (std::move (resolved_args),
{} /*binding_args*/,
TyTy::RegionParamList (0)
@@ -608,7 +696,7 @@ AssociatedImplTrait::bind_impl_for_projection (TyTy::ProjectionType &proj,
TyTy::SubstitutionArgumentMappings
AssociatedImplTrait::bind_impl_for_bound (TyTy::BaseType *receiver,
const TyTy::TypeBoundPredicate &bound,
- location_t locus)
+ location_t locus, bool emit_error)
{
// Same shape as bind_impl_for_projection but the receiver/trait-args are
// taken from the (binding, bound) pair instead of a ProjectionType.
@@ -711,6 +799,9 @@ AssociatedImplTrait::bind_impl_for_bound (TyTy::BaseType *receiver,
resolved_args.emplace_back (&p, r);
}
+ if (!validate_impl_substitution_bounds (resolved_args, locus, emit_error))
+ return TyTy::SubstitutionArgumentMappings::error ();
+
return TyTy::SubstitutionArgumentMappings (std::move (resolved_args),
{} /*binding_args*/,
TyTy::RegionParamList (0)
diff --git a/gcc/rust/typecheck/rust-type-util.cc b/gcc/rust/typecheck/rust-type-util.cc
index 5fcea2c8b..5f43bbdbe 100644
--- a/gcc/rust/typecheck/rust-type-util.cc
+++ b/gcc/rust/typecheck/rust-type-util.cc
@@ -395,7 +395,7 @@ lookup_associated_impl_block (const TyTy::TypeBoundPredicate &bound,
if (found_impl_trait)
{
// compare the bounds from here i think is what we can do:
- if (bound.is_equal (associated->get_predicate ()))
+ if (bound.get ()->is_equal (*associated->get_predicate ().get ()))
{
associated_impl_traits.push_back (associated);
}
diff --git a/gcc/rust/typecheck/rust-tyty-call.cc b/gcc/rust/typecheck/rust-tyty-call.cc
index 5a2b105e2..7ec23281a 100644
--- a/gcc/rust/typecheck/rust-tyty-call.cc
+++ b/gcc/rust/typecheck/rust-tyty-call.cc
@@ -20,6 +20,7 @@
#include "rust-hir-type-check-expr.h"
#include "rust-hir-type-check.h"
#include "rust-type-util.h"
+#include "rust-hir-trait-reference.h"
namespace Rust {
namespace TyTy {
@@ -53,6 +54,43 @@ emit_unexpected_argument_error (location_t loc,
unexpected_arg_count);
}
+static bool
+validate_call_argument_associated_impl_bounds (BaseType *param_ty,
+ BaseType *argument_ty,
+ location_t locus)
+{
+ auto *context = Resolver::TypeCheckContext::get ();
+
+ // impl bodies are checked generically
+ if (context->have_function_context ()
+ && context->peek_context ().get_type ()
+ == Resolver::TypeCheckContextItem::IMPL_ITEM)
+ return true;
+
+ auto *resolved_argument_ty = argument_ty->destructure ();
+ if (resolved_argument_ty->get_kind () == TypeKind::PARAM
+ || resolved_argument_ty->get_kind () == TypeKind::INFER
+ || resolved_argument_ty->get_kind () == TypeKind::PROJECTION)
+ return true;
+
+ for (auto bound : param_ty->get_specified_bounds ())
+ {
+ bool ambigious = false;
+ auto associated
+ = Resolver::lookup_associated_impl_block (bound, argument_ty,
+ &ambigious);
+ if (associated == nullptr)
+ continue;
+
+ auto mapping = associated->bind_impl_for_bound (argument_ty, bound, locus,
+ true /*emit_error*/);
+ if (mapping.is_error ())
+ return false;
+ }
+
+ return true;
+}
+
void
TypeCheckCallExpr::visit (ADTType &type)
{
@@ -192,6 +230,10 @@ TypeCheckCallExpr::visit (FnType &type)
{
return;
}
+
+ if (!validate_call_argument_associated_impl_bounds (
+ param_ty, argument_expr_tyty, argument->get_locus ()))
+ return;
}
else
{
@@ -420,6 +462,10 @@ TypeCheckMethodCallExpr::check (FnType &type)
return new ErrorType (type.get_ref ());
}
+ if (!validate_call_argument_associated_impl_bounds (
+ param_ty, argument_expr_tyty, argument.get_locus ()))
+ return new ErrorType (type.get_ref ());
+
i++;
}
diff --git a/gcc/testsuite/rust/compile/issue-4678.rs b/gcc/testsuite/rust/compile/issue-4678.rs
new file mode 100644
index 000000000..a088edb80
--- /dev/null
+++ b/gcc/testsuite/rust/compile/issue-4678.rs
@@ -0,0 +1,23 @@
+#![feature(no_core)]
+#![no_core]
+#![feature(lang_items)]
+
+#[lang = "sized"]
+trait Sized {}
+
+trait A {}
+trait B {}
+
+struct S<T>(T);
+
+impl<T: A> B for S<T> {}
+
+struct Bad;
+
+fn require_b<T: B>(_: T) {}
+
+fn main() {
+ let b = S(Bad);
+ require_b(b);
+ // { dg-error "the trait bound .Bad: A. is not satisfied .E0277." "" { target *-*-* } .-1 }
+}
base-commit: 79c81d0527fe0527084fc831c5ecebe5a39d30c3
--
2.54.0
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