Merge pull request #1279 from pocke/Validate_duplicate_type_aliases

Validate duplicate type aliases

lib/rbs/environment.rb

@@ -365,7 +365,7 @@ def insert_decl(decl, outer:, namespace:)
         name = decl.name.with_prefix(namespace)
 
         if interface_entry = interface_decls[name]
-          DuplicatedDeclarationError.new(name, decl, interface_entry.decl)
+          raise DuplicatedDeclarationError.new(name, decl, interface_entry.decl)
         end
 
         interface_decls[name] = InterfaceEntry.new(name: name, decl: decl, outer: outer)
@@ -374,7 +374,7 @@ def insert_decl(decl, outer:, namespace:)
         name = decl.name.with_prefix(namespace)
 
         if entry = type_alias_decls[name]
-          DuplicatedDeclarationError.new(name, decl, entry.decl)
+          raise DuplicatedDeclarationError.new(name, decl, entry.decl)
         end
 
         type_alias_decls[name] = TypeAliasEntry.new(name: name, decl: decl, outer: outer)

test/rbs/environment_test.rb

@@ -175,6 +175,36 @@ def test_const_twice_duplication_error
     end
   end
 
+  def test_type_alias_twice_duplication_error
+    env = Environment.new
+
+    _, _, decls = RBS::Parser.parse_signature(<<EOF)
+type foo = String
+type foo = Integer
+EOF
+
+    assert_raises RBS::DuplicatedDeclarationError do
+      env << decls[0]
+      env << decls[1]
+    end
+  end
+
+  def test_interface_twice_duplication_error
+    env = Environment.new
+
+    _, _, decls = RBS::Parser.parse_signature(<<EOF)
+interface _I
+end
+interface _I
+end
+EOF
+
+    assert_raises RBS::DuplicatedDeclarationError do
+      env << decls[0]
+      env << decls[1]
+    end
+  end
+
   def test_generic_class
     env = Environment.new