[COMMITTED 047/101] gccrs: Emit an error on unsafe modules

[arthur.cohen@embecosm.com]

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

An error should be emitted on unsafe modules during the AST validation
pass as the syntax allows those even though they're not alowed later down
the line.

gcc/rust/ChangeLog:

	* ast/rust-item.h: Add safety getter to modules.
	* checks/errors/rust-ast-validation.cc (ASTValidation::visit): Check
	a module's safety and emit an error when meeting an unsafe module.
	* checks/errors/rust-ast-validation.h: Add function prototype.
	* parse/rust-parse-impl.h (Parser::parse_module): Move the module locus
	to the first token instead of the mod keyword.

Signed-off-by: Pierre-Emmanuel Patry <pierre-emmanuel.patry@embecosm.com>
---
 gcc/rust/ast/rust-item.h                      |  2 ++
 gcc/rust/checks/errors/rust-ast-validation.cc | 10 ++++++++++
 gcc/rust/checks/errors/rust-ast-validation.h  |  1 +
 gcc/rust/parse/rust-parse-impl.h              |  3 ++-
 4 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/gcc/rust/ast/rust-item.h b/gcc/rust/ast/rust-item.h
index 6c3715e1eeb..3bf023b3c5a 100644
--- a/gcc/rust/ast/rust-item.h
+++ b/gcc/rust/ast/rust-item.h
@@ -840,6 +840,8 @@ public:
   // Returns the kind of the module
   enum ModuleKind get_kind () const { return kind; }
 
+  Unsafety get_unsafety () const { return safety; }
+
   // TODO: think of better way to do this - mutable getter seems dodgy
   const std::vector<Attribute> &get_inner_attrs () const { return inner_attrs; }
   std::vector<Attribute> &get_inner_attrs () { return inner_attrs; }
diff --git a/gcc/rust/checks/errors/rust-ast-validation.cc b/gcc/rust/checks/errors/rust-ast-validation.cc
index dad7f5edded..4b209908f9e 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.cc
+++ b/gcc/rust/checks/errors/rust-ast-validation.cc
@@ -17,6 +17,7 @@
 // <http://www.gnu.org/licenses/>.
 
 #include "rust-ast-validation.h"
+#include "rust-common.h"
 #include "rust-diagnostics.h"
 #include "rust-item.h"
 #include "rust-keyword-values.h"
@@ -136,4 +137,13 @@ ASTValidation::visit (AST::Trait &trait)
   AST::ContextualASTVisitor::visit (trait);
 }
 
+void
+ASTValidation::visit (AST::Module &module)
+{
+  if (module.get_unsafety () == Unsafety::Unsafe)
+    rust_error_at (module.get_locus (), "module cannot be declared unsafe");
+
+  AST::ContextualASTVisitor::visit (module);
+}
+
 } // namespace Rust
diff --git a/gcc/rust/checks/errors/rust-ast-validation.h b/gcc/rust/checks/errors/rust-ast-validation.h
index 1052168ea72..01d923ceff3 100644
--- a/gcc/rust/checks/errors/rust-ast-validation.h
+++ b/gcc/rust/checks/errors/rust-ast-validation.h
@@ -34,6 +34,7 @@ public:
 
   void check (AST::Crate &crate) { AST::ContextualASTVisitor::visit (crate); }
 
+  virtual void visit (AST::Module &module);
   virtual void visit (AST::ConstantItem &const_item);
   virtual void visit (AST::Lifetime &lifetime);
   virtual void visit (AST::LoopLabel &label);
diff --git a/gcc/rust/parse/rust-parse-impl.h b/gcc/rust/parse/rust-parse-impl.h
index 8087e0c2b94..f83cc122c89 100644
--- a/gcc/rust/parse/rust-parse-impl.h
+++ b/gcc/rust/parse/rust-parse-impl.h
@@ -2429,6 +2429,8 @@ std::unique_ptr<AST::Module>
 Parser<ManagedTokenSource>::parse_module (AST::Visibility vis,
 					  AST::AttrVec outer_attrs)
 {
+  location_t locus = lexer.peek_token ()->get_locus ();
+
   Unsafety safety = Unsafety::Normal;
   if (lexer.peek_token ()->get_id () == UNSAFE)
     {
@@ -2436,7 +2438,6 @@ Parser<ManagedTokenSource>::parse_module (AST::Visibility vis,
       skip_token (UNSAFE);
     }
 
-  location_t locus = lexer.peek_token ()->get_locus ();
   skip_token (MOD);
 
   const_TokenPtr module_name = expect_token (IDENTIFIER);
-- 
2.42.1