Basic support for lifetime parameter

This change allow for basic lifetime usage. Only syntax is checked, nothing
more. Goal is to be able to compile known-to-be-valid code.

Addresses #359

7 files changed, 176 insertions, 43 deletions

diff --git a/gcc/rust/ast/rust-ast.h b/gcc/rust/ast/rust-ast.h
index 7d3a075..b6d3401 100644
--- a/gcc/rust/ast/rust-ast.h
+++ b/gcc/rust/ast/rust-ast.h
@@ -1232,6 +1232,8 @@ class LifetimeParam : public GenericParam
   Location locus;
 
 public:
+  Lifetime get_lifetime () const { return lifetime; }
+
   // Returns whether the lifetime param has any lifetime bounds.
   bool has_lifetime_bounds () const { return !lifetime_bounds.empty (); }
 
diff --git a/gcc/rust/hir/rust-ast-lower-type.h b/gcc/rust/hir/rust-ast-lower-type.h
index 318d126..e647337 100644
--- a/gcc/rust/hir/rust-ast-lower-type.h
+++ b/gcc/rust/hir/rust-ast-lower-type.h
@@ -265,6 +265,34 @@ public:
     return resolver.translated;
   }
 
+  void visit (AST::LifetimeParam &param) override
+  {
+    auto crate_num = mappings->get_current_crate ();
+    Analysis::NodeMapping mapping (crate_num, param.get_node_id (),
+				   mappings->get_next_hir_id (crate_num),
+				   mappings->get_next_localdef_id (crate_num));
+    HIR::Lifetime::LifetimeType ltt;
+
+    switch (param.get_lifetime ().get_lifetime_type ())
+      {
+      case AST::Lifetime::LifetimeType::NAMED:
+	ltt = HIR::Lifetime::LifetimeType::NAMED;
+	break;
+      case AST::Lifetime::LifetimeType::STATIC:
+	ltt = HIR::Lifetime::LifetimeType::STATIC;
+	break;
+      case AST::Lifetime::LifetimeType::WILDCARD:
+	ltt = HIR::Lifetime::LifetimeType::WILDCARD;
+	break;
+      }
+
+    HIR::Lifetime lt (mapping, ltt, param.get_lifetime ().get_lifetime_name (),
+		      param.get_lifetime ().get_locus ());
+
+    translated = new HIR::LifetimeParam (mapping, lt, param.get_locus (),
+					 std::vector<Lifetime> ());
+  }
+
   void visit (AST::TypeParam &param) override
   {
     HIR::Attribute outer_attr = HIR::Attribute::create_empty ();
diff --git a/gcc/rust/hir/tree/rust-hir.h b/gcc/rust/hir/tree/rust-hir.h
index 9bda63a..244ff3d 100644
--- a/gcc/rust/hir/tree/rust-hir.h
+++ b/gcc/rust/hir/tree/rust-hir.h
@@ -1106,6 +1106,15 @@ class GenericParam
 public:
   virtual ~GenericParam () {}
 
+  enum GenericKind
+  {
+    TYPE,
+    LIFETIME,
+
+    // CONST generic parameter not yet handled
+    // CONST,
+  };
+
   // Unique pointer custom clone function
   std::unique_ptr<GenericParam> clone_generic_param () const
   {
@@ -1120,13 +1129,19 @@ public:
 
   Analysis::NodeMapping get_mappings () const { return mappings; }
 
+  enum GenericKind get_kind () const { return kind; }
+
 protected:
   // Clone function implementation as pure virtual method
   virtual GenericParam *clone_generic_param_impl () const = 0;
 
-  GenericParam (Analysis::NodeMapping mapping) : mappings (mapping) {}
-
   Analysis::NodeMapping mappings;
+
+  enum GenericKind kind;
+
+  GenericParam (Analysis::NodeMapping mapping, enum GenericKind kind = TYPE)
+    : mappings (mapping), kind (kind)
+  {}
 };
 
 // A lifetime generic parameter (as opposed to a type generic parameter)
@@ -1145,6 +1160,8 @@ class LifetimeParam : public GenericParam
   Location locus;
 
 public:
+  Lifetime get_lifetime () { return lifetime; }
+
   // Returns whether the lifetime param has any lifetime bounds.
   bool has_lifetime_bounds () const { return !lifetime_bounds.empty (); }
 
@@ -1160,7 +1177,8 @@ public:
 		 std::vector<Lifetime> lifetime_bounds
 		 = std::vector<Lifetime> (),
 		 Attribute outer_attr = Attribute::create_empty ())
-    : GenericParam (mappings), lifetime (std::move (lifetime)),
+    : GenericParam (mappings, GenericKind::LIFETIME),
+      lifetime (std::move (lifetime)),
       lifetime_bounds (std::move (lifetime_bounds)),
       outer_attr (std::move (outer_attr)), locus (locus)
   {}
@@ -1169,9 +1187,9 @@ public:
 
   // Copy constructor with clone
   LifetimeParam (LifetimeParam const &other)
-    : GenericParam (other.mappings), lifetime (other.lifetime),
-      lifetime_bounds (other.lifetime_bounds), outer_attr (other.outer_attr),
-      locus (other.locus)
+    : GenericParam (other.mappings, GenericKind::LIFETIME),
+      lifetime (other.lifetime), lifetime_bounds (other.lifetime_bounds),
+      outer_attr (other.outer_attr), locus (other.locus)
   {}
 
   // Overloaded assignment operator to clone attribute
diff --git a/gcc/rust/resolve/rust-ast-resolve-type.h b/gcc/rust/resolve/rust-ast-resolve-type.h
index 3d61591..d249c43 100644
--- a/gcc/rust/resolve/rust-ast-resolve-type.h
+++ b/gcc/rust/resolve/rust-ast-resolve-type.h
@@ -252,6 +252,12 @@ public:
     return resolver.resolved_node;
   };
 
+  void visit (AST::LifetimeParam &param) override
+  {
+    // For now do not do anything and accept everything.
+    ok = true;
+  }
+
   void visit (AST::TypeParam &param) override
   {
     ok = true;
diff --git a/gcc/rust/typecheck/rust-hir-type-check-implitem.h b/gcc/rust/typecheck/rust-hir-type-check-implitem.h
index 8ab20cf..2a3e9f9 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-implitem.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-implitem.h
@@ -59,12 +59,24 @@ public:
       {
 	for (auto &generic_param : function.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
@@ -111,12 +123,24 @@ public:
       {
 	for (auto &generic_param : method.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
@@ -180,7 +204,7 @@ private:
 
   TyTy::BaseType *self;
   std::vector<TyTy::SubstitutionParamMapping> substitutions;
-};
+}; // namespace Resolver
 
 class TypeCheckImplItem : public TypeCheckBase
 {
diff --git a/gcc/rust/typecheck/rust-hir-type-check-toplevel.h b/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
index 1bfa7fb..6be1552 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
+++ b/gcc/rust/typecheck/rust-hir-type-check-toplevel.h
@@ -55,12 +55,24 @@ public:
       {
 	for (auto &generic_param : struct_decl.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
@@ -95,12 +107,24 @@ public:
       {
 	for (auto &generic_param : struct_decl.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
@@ -152,12 +176,24 @@ public:
       {
 	for (auto &generic_param : function.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
@@ -205,12 +241,24 @@ public:
       {
 	for (auto &generic_param : impl_block.get_generic_params ())
 	  {
-	    auto param_type
-	      = TypeResolveGenericParam::Resolve (generic_param.get ());
-	    context->insert_type (generic_param->get_mappings (), param_type);
-
-	    substitutions.push_back (TyTy::SubstitutionParamMapping (
-	      static_cast<HIR::TypeParam &> (*generic_param), param_type));
+	    switch (generic_param.get ()->get_kind ())
+	      {
+	      case HIR::GenericParam::GenericKind::LIFETIME:
+		// Skipping Lifetime completely until better handling.
+		break;
+
+		case HIR::GenericParam::GenericKind::TYPE: {
+		  auto param_type
+		    = TypeResolveGenericParam::Resolve (generic_param.get ());
+		  context->insert_type (generic_param->get_mappings (),
+					param_type);
+
+		  substitutions.push_back (TyTy::SubstitutionParamMapping (
+		    static_cast<HIR::TypeParam &> (*generic_param),
+		    param_type));
+		}
+		break;
+	      }
 	  }
       }
 
diff --git a/gcc/testsuite/rust.test/compile/lifetime1.rs b/gcc/testsuite/rust.test/compile/lifetime1.rs
new file mode 100644
index 0000000..151fd82
--- /dev/null
+++ b/gcc/testsuite/rust.test/compile/lifetime1.rs
@@ -0,0 +1,7 @@
+fn foo<'a>(t: &'a str) -> &'a str {
+    t
+}
+
+fn main() {
+    foo("hello world");
+}