From 25beb215fcf4b7af81ea4508e4d932796f1ae4ce Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Fournier?= <clement.fournier76@gmail.com>
Date: Wed, 1 Jul 2020 11:14:55 +0200
Subject: [PATCH] Throw on incompatible visitor type

---
 antlr4-wrapper.xml                                       | 2 +-
 .../src/main/java/net/sourceforge/pmd/lang/ast/Node.java | 9 ++++++++-
 .../sourceforge/pmd/lang/java/ast/AbstractJavaNode.java  | 2 +-
 .../sourceforge/pmd/lang/jsp/ast/AbstractJspNode.java    | 2 +-
 .../pmd/lang/scala/ast/AbstractScalaNode.java            | 2 +-
 5 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/antlr4-wrapper.xml b/antlr4-wrapper.xml
index 61f9c5fddf..f6a221708b 100644
--- a/antlr4-wrapper.xml
+++ b/antlr4-wrapper.xml
@@ -51,7 +51,7 @@
                            value="((${visitor-name}&lt;? super P, ? extends R>) visitor)" />
 
             <replacefilter token="return visitor.visitChildren(this);"
-                           value="return visitor.visitNode(this, data);" />
+                           value="return super.acceptVisitor(visitor, data);" />
 
         </replace>
 
diff --git a/pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java b/pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java
index 8e15b071eb..52e93c486d 100644
--- a/pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java
+++ b/pmd-core/src/main/java/net/sourceforge/pmd/lang/ast/Node.java
@@ -296,11 +296,18 @@ public interface Node {
      * @param data    Parameter to the visit
      *
      * @return What the visitor returned
+     *
+     * @throws IllegalArgumentException If the visitor is incompatible with this node
+     *
+     * @implSpec A typical implementation will check the type of the visitor to
+     *     be that of the language specific visitor, then call the most specific
+     *     visit method of this Node. This is typically implemented by having
+     *     a different override per concrete node class (no shortcuts).
      */
     // TODO remove the default implementation, convert all visitors to be generic
     default <P, R> R acceptVisitor(AstVisitor<? super P, ? extends R> visitor, P data) {
         // override me
-        return visitor.visitNode(this, data);
+        throw new IllegalArgumentException("Unsupported visitor" + visitor + " for node " + this);
     }
 
 
diff --git a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/AbstractJavaNode.java b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/AbstractJavaNode.java
index a50522a092..79681561a4 100644
--- a/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/AbstractJavaNode.java
+++ b/pmd-java/src/main/java/net/sourceforge/pmd/lang/java/ast/AbstractJavaNode.java
@@ -38,7 +38,7 @@ public abstract class AbstractJavaNode extends AbstractJjtreeNode<AbstractJavaNo
         if (visitor instanceof JavaVisitor) {
             return this.acceptVisitor((JavaVisitor<? super P, ? extends R>) visitor, data);
         }
-        return visitor.visitNode(this, data);
+        return super.acceptVisitor(visitor, data);
     }
 
     protected abstract <P, R> R acceptVisitor(JavaVisitor<? super P, ? extends R> visitor, P data);
diff --git a/pmd-jsp/src/main/java/net/sourceforge/pmd/lang/jsp/ast/AbstractJspNode.java b/pmd-jsp/src/main/java/net/sourceforge/pmd/lang/jsp/ast/AbstractJspNode.java
index d325167911..a0c2c53c57 100644
--- a/pmd-jsp/src/main/java/net/sourceforge/pmd/lang/jsp/ast/AbstractJspNode.java
+++ b/pmd-jsp/src/main/java/net/sourceforge/pmd/lang/jsp/ast/AbstractJspNode.java
@@ -18,7 +18,7 @@ abstract class AbstractJspNode extends AbstractJjtreeNode<AbstractJspNode, JspNo
         if (visitor instanceof JspVisitor) {
             return this.acceptVisitor((JspVisitor<? super P, ? extends R>) visitor, data);
         }
-        return visitor.visitNode(this, data);
+        return super.acceptVisitor(visitor, data);
     }
 
     protected abstract <P, R> R acceptVisitor(JspVisitor<? super P, ? extends R> visitor, P data);
diff --git a/pmd-scala-modules/pmd-scala-common/src/main/java/net/sourceforge/pmd/lang/scala/ast/AbstractScalaNode.java b/pmd-scala-modules/pmd-scala-common/src/main/java/net/sourceforge/pmd/lang/scala/ast/AbstractScalaNode.java
index caf0f8e2c0..3f4810296a 100644
--- a/pmd-scala-modules/pmd-scala-common/src/main/java/net/sourceforge/pmd/lang/scala/ast/AbstractScalaNode.java
+++ b/pmd-scala-modules/pmd-scala-common/src/main/java/net/sourceforge/pmd/lang/scala/ast/AbstractScalaNode.java
@@ -38,7 +38,7 @@ abstract class AbstractScalaNode<T extends Tree> extends AbstractNode<AbstractSc
         if (visitor instanceof ScalaParserVisitor) {
             return this.acceptVisitor((ScalaParserVisitor<P, R>) visitor, data);
         }
-        return visitor.visitNode(this, data);
+        return super.acceptVisitor(visitor, data);
     }
 
     protected abstract <P, R> R acceptVisitor(ScalaParserVisitor<? super P, ? extends R> visitor, P data);