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.philip@googlemail.com>

diff --git a/gcc/rust/ast/rust-desugar-apit.cc b/gcc/rust/ast/rust-desugar-apit.cc
index 2f31bcfe7a327c499c90c34eeb27ac2a915aa90e..5b9486ea6714c11228581bab78b644742b3e491b 100644 (file)
--- 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 f507c90dc962b005b85c16eadb97712b0ab2b831..2f53f8d117e4e41b5c72a7a8d88bec19d85e772e 100644 (file)
--- 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 6a5b7dba866c3933c6943a7faed71dbce892e7f0..b83d8043800e979428de72a31c8d6b8b90d8d6ae 100644 (file)
--- 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 &param)
   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 160f710408af430e9926935bcf5ba934ea38391e..1406e7aeb51566d724aaff981c48a7ec123fdef8 100644 (file)
--- 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 41ba38c4f6d74630623df711d7049e5b05a5bbe9..dc8f9f9dd7a818fa504fe43b9f5fb311757c60af 100644 (file)
--- 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 c3033eed5f7d16ef255e9c71141e1466fa5d8392..8279c8feacd46d24210eafb514dd2faddd4b68c3 100644 (file)
--- 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 &param_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 (&param_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 8a43b917a54f6a724e1bc3f6b6e298330d2eb19a..084b453c7c5159e0dd50c39dfa835e82d5e188e0 100644 (file)
--- 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 (file)
index 0000000..ecdb088
--- /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 d3bdb1cce0dfe5f0af74c7d823c7a7a5ae20a48b..b9b9e39aa82c4c9bba7c44c6ff261603c3c022eb 100644 (file)
--- 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