[gcc r14-8587] gccrs: Add validation for functions without body

[Arthur Cohen]

https://gcc.gnu.org/g:04fd5a043b08fdc4d4e60499b8fd83d02007a737

commit r14-8587-g04fd5a043b08fdc4d4e60499b8fd83d02007a737
Author: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
Date:   Wed Nov 22 16:37:17 2023 +0100

    gccrs: Add validation for functions without body
    
    Add checks in the ast validation pass to error out with functions
    (either free or associated) without a definition.
    
    gcc/rust/ChangeLog:
    
            * checks/errors/rust-ast-validation.cc (ASTValidation::visit): Add
            a validation check and emit an error depending on the context.
    
    Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>

Diff:
---
 gcc/rust/checks/errors/rust-ast-validation.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/gcc/rust/checks/errors/rust-ast-validation.cc b/gcc/rust/checks/errors/rust-ast-validation.cc
index 2743eb0ca299..6fb142c78455 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.cc
+++ b/gcc/rust/checks/errors/rust-ast-validation.cc
@@ -109,6 +109,16 @@ ASTValidation::visit (AST::Function &function)
       function.get_self_param ()->get_locus (),
       "%<self%> parameter is only allowed in associated functions");
 
+  if (!function.has_body ())
+    {
+      if (context.back () == Context::INHERENT_IMPL
+	  || context.back () == Context::TRAIT_IMPL)
+	rust_error_at (function.get_locus (),
+		       "associated function in %<impl%> without body");
+      else if (context.back () != Context::TRAIT)
+	rust_error_at (function.get_locus (), "free function without a body");
+    }
+
   if (function.is_variadic ())
     rust_error_at (
       function.get_function_params ().back ()->get_locus (),