[COMMITTED 055/101] gccrs: Add AST validation check for const in trait

[arthur . cohen]

From: Pierre-Emmanuel Patry <pierre-emmanuel.pa...@embecosm.com>

Add a new check in AST validation pass that checks that no function
declaration in traits are declared const.

gcc/rust/ChangeLog:

        * checks/errors/rust-ast-validation.cc (ASTValidation::visit): Add
        const check.
        * checks/errors/rust-ast-validation.h: Add visit function prototype.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.pa...@embecosm.com>
---
 gcc/rust/checks/errors/rust-ast-validation.cc | 10 ++++++++++
 gcc/rust/checks/errors/rust-ast-validation.h  |  1 +
 2 files changed, 11 insertions(+)

diff --git a/gcc/rust/checks/errors/rust-ast-validation.cc 
b/gcc/rust/checks/errors/rust-ast-validation.cc
index 54276e8fd59..2743eb0ca29 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.cc
+++ b/gcc/rust/checks/errors/rust-ast-validation.cc
@@ -117,6 +117,16 @@ ASTValidation::visit (AST::Function &function)
   AST::ContextualASTVisitor::visit (function);
 }
 
+void
+ASTValidation::visit (AST::TraitFunctionDecl &decl)
+{
+  const auto &qualifiers = decl.get_qualifiers ();
+
+  if (context.back () == Context::TRAIT && qualifiers.is_const ())
+    rust_error_at (decl.get_identifier ().get_locus (), ErrorCode::E0379,
+                  "functions in traits cannot be declared const");
+}
+
 void
 ASTValidation::visit (AST::Trait &trait)
 {
diff --git a/gcc/rust/checks/errors/rust-ast-validation.h 
b/gcc/rust/checks/errors/rust-ast-validation.h
index 01d923ceff3..963357f86cd 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.h
+++ b/gcc/rust/checks/errors/rust-ast-validation.h
@@ -42,6 +42,7 @@ public:
   virtual void visit (AST::Union &item);
   virtual void visit (AST::Function &function);
   virtual void visit (AST::Trait &trait);
+  virtual void visit (AST::TraitFunctionDecl &decl);
 };
 
 } // namespace Rust
-- 
2.42.1