gccrs: Add typecheck for path patterns.

gcc/rust/ChangeLog:

	* hir/tree/rust-hir.cc (Item::item_kind_string): New function.
	* hir/tree/rust-hir.h: New function.
	* typecheck/rust-hir-type-check-expr.cc (TypeCheckExpr::visit):
		Modify to check all arms in match expressions even if some of them
		has errors.
	* typecheck/rust-hir-type-check-pattern.cc (TypeCheckPattern::visit):
		Add and fix check for path patterns.

gcc/testsuite/ChangeLog:

	* rust/compile/issue-2324-2.rs: Fix error message.
	* rust/compile/match9.rs: New test.

Signed-off-by: Raiki Tamura <tamaron1203@gmail.com>

6 files changed, 175 insertions, 28 deletions

diff --git a/gcc/rust/hir/tree/rust-hir.cc b/gcc/rust/hir/tree/rust-hir.cc
index 35aa585..797a7fb 100644
--- a/gcc/rust/hir/tree/rust-hir.cc
+++ b/gcc/rust/hir/tree/rust-hir.cc
@@ -213,6 +213,44 @@ Module::as_string () const
 }
 
 std::string
+Item::item_kind_string (Item::ItemKind kind)
+{
+  switch (kind)
+    {
+    case Item::ItemKind::Static:
+      return "static";
+    case Item::ItemKind::Constant:
+      return "constant";
+    case Item::ItemKind::TypeAlias:
+      return "type alias";
+    case Item::ItemKind::Function:
+      return "function";
+    case Item::ItemKind::UseDeclaration:
+      return "use declaration";
+    case Item::ItemKind::ExternBlock:
+      return "extern block";
+    case Item::ItemKind::ExternCrate:
+      return "extern crate";
+    case Item::ItemKind::Struct:
+      return "struct";
+    case Item::ItemKind::Union:
+      return "union";
+    case Item::ItemKind::Enum:
+      return "enum";
+    case Item::ItemKind::EnumItem:
+      return "enum item";
+    case Item::ItemKind::Trait:
+      return "trait";
+    case Item::ItemKind::Impl:
+      return "impl";
+    case Item::ItemKind::Module:
+      return "module";
+    default:
+      rust_unreachable ();
+    }
+}
+
+std::string
 StaticItem::as_string () const
 {
   std::string str = VisItem::as_string ();
diff --git a/gcc/rust/hir/tree/rust-hir.h b/gcc/rust/hir/tree/rust-hir.h
index 3fb97b2..e612499 100644
--- a/gcc/rust/hir/tree/rust-hir.h
+++ b/gcc/rust/hir/tree/rust-hir.h
@@ -220,6 +220,8 @@ public:
     Module,
   };
 
+  static std::string item_kind_string (ItemKind kind);
+
   virtual ItemKind get_item_kind () const = 0;
 
   // Unique pointer custom clone function
diff --git a/gcc/rust/typecheck/rust-hir-type-check-expr.cc b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
index 8a1460b..12a8b65 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-expr.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-expr.cc
@@ -1465,6 +1465,7 @@ TypeCheckExpr::visit (HIR::MatchExpr &expr)
   TyTy::BaseType *scrutinee_tyty
     = TypeCheckExpr::Resolve (expr.get_scrutinee_expr ().get ());
 
+  bool saw_error = false;
   std::vector<TyTy::BaseType *> kase_block_tys;
   for (auto &kase : expr.get_match_cases ())
     {
@@ -1475,7 +1476,10 @@ TypeCheckExpr::visit (HIR::MatchExpr &expr)
 	  TyTy::BaseType *kase_arm_ty
 	    = TypeCheckPattern::Resolve (pattern.get (), scrutinee_tyty);
 	  if (kase_arm_ty->get_kind () == TyTy ::TypeKind::ERROR)
-	    return;
+	    {
+	      saw_error = true;
+	      continue;
+	    }
 
 	  TyTy::BaseType *checked_kase = unify_site (
 	    expr.get_mappings ().get_hirid (),
@@ -1484,7 +1488,10 @@ TypeCheckExpr::visit (HIR::MatchExpr &expr)
 	    TyTy::TyWithLocation (kase_arm_ty, pattern->get_locus ()),
 	    expr.get_locus ());
 	  if (checked_kase->get_kind () == TyTy::TypeKind::ERROR)
-	    return;
+	    {
+	      saw_error = true;
+	      continue;
+	    }
 	}
 
       // check the kase type
@@ -1492,6 +1499,8 @@ TypeCheckExpr::visit (HIR::MatchExpr &expr)
 	= TypeCheckExpr::Resolve (kase.get_expr ().get ());
       kase_block_tys.push_back (kase_block_ty);
     }
+  if (saw_error)
+    return;
 
   if (kase_block_tys.size () == 0)
     {
diff --git a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
index 811e329..b0e4ca5 100644
--- a/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
+++ b/gcc/rust/typecheck/rust-hir-type-check-pattern.cc
@@ -43,32 +43,100 @@ TypeCheckPattern::Resolve (HIR::Pattern *pattern, TyTy::BaseType *parent)
 void
 TypeCheckPattern::visit (HIR::PathInExpression &pattern)
 {
-  infered = TypeCheckExpr::Resolve (&pattern);
-
-  /*
-   * We are compiling a PathInExpression, which can't be a Struct or Tuple
-   * pattern. We should check that the declaration we are referencing IS NOT a
-   * struct pattern or tuple with values.
-   */
+  // Pattern must be enum variants, sturcts, constants, or associated constansts
+  TyTy::BaseType *pattern_ty = TypeCheckExpr::Resolve (&pattern);
+
+  NodeId ref_node_id = UNKNOWN_NODEID;
+  bool maybe_item = false;
+  maybe_item
+    |= resolver->lookup_resolved_name (pattern.get_mappings ().get_nodeid (),
+				       &ref_node_id);
+  maybe_item
+    |= resolver->lookup_resolved_type (pattern.get_mappings ().get_nodeid (),
+				       &ref_node_id);
+  bool path_is_const_item = false;
+
+  if (maybe_item)
+    {
+      tl::optional<HirId> definition_id
+	= mappings.lookup_node_to_hir (ref_node_id);
+      rust_assert (definition_id.has_value ());
+      HirId def_id = definition_id.value ();
+
+      tl::optional<HIR::Item *> hir_item = mappings.lookup_hir_item (def_id);
+      // If the path refrerences an item, it must be constants or structs.
+      if (hir_item.has_value ())
+	{
+	  HIR::Item *item = hir_item.value ();
+	  if (item->get_item_kind () == HIR::Item::ItemKind::Constant)
+	    {
+	      path_is_const_item = true;
+	    }
+	  else if (item->get_item_kind () != HIR::Item::ItemKind::Struct)
+	    {
+	      HIR::Item *item = hir_item.value ();
+	      std::string item_kind
+		= HIR::Item::item_kind_string (item->get_item_kind ());
+
+	      std::string path_buf;
+	      for (size_t i = 0; i < pattern.get_segments ().size (); i++)
+		{
+		  HIR::PathExprSegment &seg = pattern.get_segments ().at (i);
+		  path_buf += seg.as_string ();
+		  if (i != pattern.get_segments ().size () - 1)
+		    path_buf += "::";
+		}
+
+	      rich_location rich_locus (
+		line_table, pattern.get_final_segment ().get_locus ());
+	      rich_locus.add_fixit_replace (
+		"not a unit struct, unit variant or constatnt");
+	      rust_error_at (rich_locus, ErrorCode::E0532,
+			     "expected unit struct, unit variant or constant, "
+			     "found %s %<%s%>",
+			     item_kind.c_str (), path_buf.c_str ());
+	      return;
+	    }
+	}
+    }
 
-  rust_assert (infered->get_kind () == TyTy::TypeKind::ADT);
-  TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (infered);
+  // If the path is a constructor, it must be a unit struct or unit variants.
+  if (!path_is_const_item && pattern_ty->get_kind () == TyTy::TypeKind::ADT)
+    {
+      TyTy::ADTType *adt = static_cast<TyTy::ADTType *> (pattern_ty);
+      rust_assert (adt->get_variants ().size () > 0);
 
-  HirId variant_id = UNKNOWN_HIRID;
-  bool ok
-    = context->lookup_variant_definition (pattern.get_mappings ().get_hirid (),
-					  &variant_id);
-  rust_assert (ok);
+      TyTy::VariantDef *variant = adt->get_variants ().at (0);
+      if (adt->is_enum ())
+	{
+	  HirId variant_id = UNKNOWN_HIRID;
+	  bool ok = context->lookup_variant_definition (
+	    pattern.get_mappings ().get_hirid (), &variant_id);
+	  rust_assert (ok);
 
-  TyTy::VariantDef *variant = nullptr;
-  ok = adt->lookup_variant_by_id (variant_id, &variant);
+	  ok = adt->lookup_variant_by_id (variant_id, &variant);
+	  rust_assert (ok);
+	}
 
-  TyTy::VariantDef::VariantType vty = variant->get_variant_type ();
+      if (variant->get_variant_type () != TyTy::VariantDef::VariantType::NUM)
+	{
+	  std::string variant_type = TyTy::VariantDef::variant_type_string (
+	    variant->get_variant_type ());
+
+	  rich_location rich_locus (line_table,
+				    pattern.get_final_segment ().get_locus ());
+	  rich_locus.add_fixit_replace (
+	    "not a unit struct, unit variant or constatnt");
+	  rust_error_at (rich_locus, ErrorCode::E0532,
+			 "expected unit struct, unit variant or constant, "
+			 "found %s variant %<%s::%s%>",
+			 variant_type.c_str (), adt->get_name ().c_str (),
+			 variant->get_identifier ().c_str ());
+	  return;
+	}
 
-  if (vty != TyTy::VariantDef::VariantType::NUM)
-    rust_error_at (
-      pattern.get_final_segment ().get_locus (), ErrorCode::E0532,
-      "expected unit struct, unit variant or constant, found tuple variant");
+      infered = pattern_ty;
+    }
 }
 
 void
@@ -100,8 +168,8 @@ TypeCheckPattern::visit (HIR::TupleStructPattern &pattern)
       rust_assert (ok);
     }
 
-  // error[E0532]: expected tuple struct or tuple variant, found struct variant
-  // `Foo::D`, E0532 by rustc 1.49.0 , E0164 by rustc 1.71.0
+  // error[E0532]: expected tuple struct or tuple variant, found struct
+  // variant `Foo::D`, E0532 by rustc 1.49.0 , E0164 by rustc 1.71.0
   if (variant->get_variant_type () != TyTy::VariantDef::VariantType::TUPLE)
     {
       std::string variant_type
@@ -203,8 +271,8 @@ TypeCheckPattern::visit (HIR::StructPattern &pattern)
       rust_assert (ok);
     }
 
-  // error[E0532]: expected tuple struct or tuple variant, found struct variant
-  // `Foo::D`
+  // error[E0532]: expected tuple struct or tuple variant, found struct
+  // variant `Foo::D`
   if (variant->get_variant_type () != TyTy::VariantDef::VariantType::STRUCT)
     {
       std::string variant_type
diff --git a/gcc/testsuite/rust/compile/issue-2324-2.rs b/gcc/testsuite/rust/compile/issue-2324-2.rs
index 5ef4014..1530b00 100644
--- a/gcc/testsuite/rust/compile/issue-2324-2.rs
+++ b/gcc/testsuite/rust/compile/issue-2324-2.rs
@@ -6,7 +6,7 @@ enum State {
 fn print_on_failure(state: &State) {
     match *state {
         State::Succeeded => (),
-        State::Failed => (), // { dg-error "expected unit struct, unit variant or constant, found tuple variant" }
+        State::Failed => (), // { dg-error "expected unit struct, unit variant or constant, found struct variant" }
         _ => ()
     }
 }
diff --git a/gcc/testsuite/rust/compile/match9.rs b/gcc/testsuite/rust/compile/match9.rs
new file mode 100644
index 0000000..115d458
--- /dev/null
+++ b/gcc/testsuite/rust/compile/match9.rs
@@ -0,0 +1,30 @@
+enum E {
+    A(),
+    B,
+}
+
+const CONST_E: E = E::A();
+
+static static_e: E = E::A();
+
+type type_alias = E;
+
+fn f(e: E) {
+    match e {
+        E::A => {}
+        // { dg-error "expected unit struct, unit variant or constant, found tuple variant .E::A." "" { target *-*-* } .-1 }
+        E::B => {}
+        crate::CONST_E => {}
+        crate::type_alias => {}
+        // { dg-error "expected unit struct, unit variant or constant, found type alias .crate::type_alias." "" { target *-*-* } .-1 }
+        crate::E => {}
+        // { dg-error "expected unit struct, unit variant or constant, found enum .crate::E." "" { target *-*-* } .-1 }
+        crate::static_e => {}
+        // { dg-error "expected unit struct, unit variant or constant, found static .crate::static_e." "" { target *-*-* } .-1 }
+        crate::f => {}
+        // { dg-error "expected unit struct, unit variant or constant, found function .crate::f." "" { target *-*-* } .-1 }
+        _ => {}
+    }
+}
+
+fn main() {}