Compiler: don't visit enum member expanded by macro twice (#10105)

spec/compiler/semantic/enum_spec.cr

@@ -492,4 +492,19 @@ describe "Semantic: enum" do
       end
     ))
   end
+
+  it "doesn't visit enum members generated by macros twice (#10104)" do
+    result = semantic(%(
+      enum Foo
+        A = 1
+
+        {% begin %}
+          def foo
+          end
+        {% end %}
+      end
+      ))
+    a_def = result.program.types["Foo"].lookup_defs("foo").first
+    a_def.previous.should be_nil
+  end
 end

src/compiler/crystal/semantic/semantic_visitor.cr

@@ -269,11 +269,11 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
     node.raise "can't #{op} dynamically" if inside_exp?
   end
 
-  def expand_macro(node, raise_on_missing_const = true, first_pass = false)
+  def expand_macro(node, raise_on_missing_const = true, first_pass = false, accept = true)
     if expanded = node.expanded
       @exp_nest -= 1
       eval_macro(node) do
-        expanded.accept self
+        expanded.accept self if accept
       end
       @exp_nest += 1
       return true
@@ -311,7 +311,7 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
     args = expand_macro_arguments(node, expansion_scope)
 
     @exp_nest -= 1
-    generated_nodes = expand_macro(the_macro, node, visibility: node.visibility) do
+    generated_nodes = expand_macro(the_macro, node, visibility: node.visibility, accept: accept) do
       old_args = node.args
       node.args = args
       expanded_macro, macro_expansion_pragmas = @program.expand_macro the_macro, node, expansion_scope, expansion_scope, @untyped_def
@@ -327,7 +327,7 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
     true
   end
 
-  def expand_macro(the_macro, node, mode = nil, *, visibility : Visibility)
+  def expand_macro(the_macro, node, mode = nil, *, visibility : Visibility, accept = true)
     expanded_macro, macro_expansion_pragmas =
       eval_macro(node) do
         yield
@@ -357,7 +357,7 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
       generated_nodes.accept PropagateDocVisitor.new(node_doc)
     end
 
-    generated_nodes.accept self
+    generated_nodes.accept self if accept
     generated_nodes
   end
 
@@ -406,10 +406,10 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
     args
   end
 
-  def expand_inline_macro(node, mode = nil)
+  def expand_inline_macro(node, mode = nil, accept = true)
     if expanded = node.expanded
       eval_macro(node) do
-        expanded.accept self
+        expanded.accept self if accept
       end
       return expanded
     end
@@ -418,7 +418,7 @@ abstract class Crystal::SemanticVisitor < Crystal::Visitor
 
     skip_macro_exception = nil
 
-    generated_nodes = expand_macro(the_macro, node, mode: mode, visibility: :public) do
+    generated_nodes = expand_macro(the_macro, node, mode: mode, visibility: :public, accept: accept) do
       begin
         @program.expand_macro node, (@scope || current_type), @path_lookup, free_vars, @untyped_def
       rescue ex : SkipMacroException

src/compiler/crystal/semantic/top_level_visitor.cr

@@ -381,6 +381,7 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
     end
 
     target_type.add_def node
+
     node.set_type @program.nil
 
     if is_instance_method
@@ -633,13 +634,13 @@ class Crystal::TopLevelVisitor < Crystal::SemanticVisitor
   def visit_enum_member(node, member, counter, all_value, overflow, **options)
     case member
     when MacroIf
-      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum)
+      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum, accept: false)
       visit_enum_member(node, expanded, counter, all_value, overflow, **options)
     when MacroExpression
-      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum)
+      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum, accept: false)
       visit_enum_member(node, expanded, counter, all_value, overflow, **options)
     when MacroFor
-      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum)
+      expanded = expand_inline_macro(member, mode: Parser::ParseMode::Enum, accept: false)
       visit_enum_member(node, expanded, counter, all_value, overflow, **options)
     when Expressions
       visit_enum_members(node, member.expressions, counter, all_value, overflow, **options)