[ruby] public in a Method body is lowered to SimpleCall (#5122)

* Fixed warning on calling function that shadows a reserved keyword

* Moved lowering to AstCreator

joern-cli/frontends/rubysrc2cpg/src/main/scala/io/joern/rubysrc2cpg/astcreation/AstForStatementsCreator.scala

@@ -5,9 +5,10 @@ import io.joern.rubysrc2cpg.datastructures.BlockScope
 import io.joern.rubysrc2cpg.parser.RubyJsonHelpers
 import io.joern.rubysrc2cpg.passes.Defines
 import io.joern.rubysrc2cpg.passes.Defines.getBuiltInType
+import io.joern.x2cpg.datastructures.MethodLike
 import io.joern.x2cpg.{Ast, ValidationMode}
 import io.shiftleft.codepropertygraph.generated.nodes.{NewBlock, NewControlStructure}
-import io.shiftleft.codepropertygraph.generated.{ControlStructureTypes, ModifierTypes}
+import io.shiftleft.codepropertygraph.generated.{ControlStructureTypes, ModifierTypes, NodeTypes}
 
 trait AstForStatementsCreator(implicit withSchemaValidation: ValidationMode) { this: AstCreator =>
 
@@ -22,7 +23,7 @@ trait AstForStatementsCreator(implicit withSchemaValidation: ValidationMode) { t
       case node: AnonymousTypeDeclaration   => astForAnonymousTypeDeclaration(node) :: Nil
       case node: TypeDeclaration            => astForClassDeclaration(node)
       case node: FieldsDeclaration          => astsForFieldDeclarations(node)
-      case node: AccessModifier             => registerAccessModifier(node)
+      case node: AccessModifier             => astForAccessModifier(node)
       case node: MethodDeclaration          => astForMethodDeclaration(node)
       case node: MethodAccessModifier       => astForMethodAccessModifier(node)
       case node: SingletonMethodDeclaration => astForSingletonMethodDeclaration(node)
@@ -73,6 +74,16 @@ trait AstForStatementsCreator(implicit withSchemaValidation: ValidationMode) { t
     controlStructureAst(ifNode, Some(conditionAst), thenAst +: elseAsts) :: Nil
   }
 
+  private def astForAccessModifier(node: AccessModifier): Seq[Ast] = {
+    scope.surroundingAstLabel match {
+      case Some(x) if x == NodeTypes.METHOD =>
+        val simpleIdent = node.toSimpleIdentifier
+        astForSimpleCall(SimpleCall(simpleIdent, List.empty)(simpleIdent.span)) :: Nil
+      case _ =>
+        registerAccessModifier(node)
+    }
+  }
+
   /** Registers the currently set access modifier for the current type (until it is reset later).
     */
   private def registerAccessModifier(node: AccessModifier): Seq[Ast] = {
@@ -224,6 +235,10 @@ trait AstForStatementsCreator(implicit withSchemaValidation: ValidationMode) { t
         stmts.map(astForExpression) ++ astsForImplicitReturnStatement(nilReturnLiteral)
       case x: RangeExpression =>
         astForReturnRangeExpression(x) :: Nil
+      case node: AccessModifier =>
+        val simpleIdent = node.toSimpleIdentifier
+        val simpleCall  = SimpleCall(simpleIdent, List.empty)(simpleIdent.span)
+        astForReturnExpression(ReturnExpression(List(simpleCall))(node.span)) :: Nil
       case node =>
         logger.warn(s" not supported yet: ${node.text} (${node.getClass.getSimpleName}), only generating statement")
         astsForStatement(node).toList

joern-cli/frontends/rubysrc2cpg/src/test/scala/io/joern/rubysrc2cpg/querying/MethodTests.scala

@@ -1064,4 +1064,38 @@ class MethodTests extends RubyCode2CpgFixture {
       case xs => fail(s"Expected one return, got [${xs.code.mkString(",")}]")
     }
   }
+
+  "Method call with same name as reserved keyword" in {
+    val cpg = code("""
+        |    def public
+        |      list.sort_by(&:position).filter_map { |category| category.slug if category.visible_to_public? }
+        |    end
+        |
+        |    def notifiable
+        |      public
+        |    end
+        |
+        |    def not_notifiable
+        |       public
+        |       puts 1
+        |       puts 2
+        |    end
+        |""".stripMargin)
+
+    inside(cpg.method.name("notifiable").body.astChildren.isReturn.astChildren.isCall.name("public").l) {
+      case publicCall :: Nil =>
+        publicCall.code shouldBe "public"
+
+        val List(selfArg) = publicCall.argument.l
+      case xs => fail(s"Expected one call, got ${xs.code.mkString(",")}")
+    }
+
+    inside(cpg.method.name("not_notifiable").body.astChildren.isCall.name("public").l) {
+      case publicCall :: Nil =>
+        publicCall.code shouldBe "public"
+
+        val List(selfArg) = publicCall.argument.l
+      case xs => fail(s"Expected one call, got ${xs.code.mkString(",")}")
+    }
+  }
 }