Add a useful toString() for Ruby*SourceNode and RubyCallNode

Author: eregon

src/main/java/org/truffleruby/language/RubyContextSourceNode.java

@@ -72,4 +72,10 @@ public RubyContext getContext() {
 
         return contextReference.get();
     }
+
+    @Override
+    public String toString() {
+        return super.toString() + " at " + RubyContext.fileLine(getSourceSection());
+    }
+
 }

src/main/java/org/truffleruby/language/RubySourceNode.java

@@ -32,4 +32,9 @@ public Object isDefined(VirtualFrame frame, RubyContext context) {
         return RubyNode.defaultIsDefined(context, this);
     }
 
+    @Override
+    public String toString() {
+        return super.toString() + " at " + RubyContext.fileLine(getSourceSection());
+    }
+
 }

src/main/java/org/truffleruby/language/dispatch/RubyCallNode.java

@@ -31,6 +31,8 @@
 import com.oracle.truffle.api.profiles.ConditionProfile;
 import org.truffleruby.language.methods.LookupMethodOnSelfNode;
 
+import java.util.Map;
+
 import static org.truffleruby.language.dispatch.DispatchConfiguration.PRIVATE;
 import static org.truffleruby.language.dispatch.DispatchConfiguration.PRIVATE_RETURN_MISSING;
 import static org.truffleruby.language.dispatch.DispatchConfiguration.PROTECTED;
@@ -173,6 +175,13 @@ public boolean hasLiteralBlock() {
         return hasLiteralBlock;
     }
 
+    @Override
+    public Map<String, Object> getDebugProperties() {
+        final Map<String, Object> map = super.getDebugProperties();
+        map.put("methodName", methodName);
+        return map;
+    }
+
     private class DefinedNode extends RubyBaseNode {
 
         private final RubySymbol methodNameSymbol = getContext().getSymbol(methodName);