parse.y (java_complete_lhs): Only allow compound assignment of reference type if type is String.

	* parse.y (java_complete_lhs): Only allow compound assignment of
	reference type if type is String.

Co-Authored-By: Alexandre Petit-Bianco <apbianco@cygnus.com>

From-SVN: r38236

gcc/java/ChangeLog

+2000-11-20  Tom Tromey  <tromey@cygnus.com>
+            Alexandre Petit-Bianco  <apbianco@cygnus.com>
+
+	* parse.y (java_complete_lhs): Only allow compound assignment of
+	reference type if type is String.
+
 2000-12-09  Alexandre Petit-Bianco  <apbianco@cygnus.com>
 
 	* Make-lang.in (java/jcf-path.o:): libgcj.jar replaces libgcj.zip.

gcc/java/parse.y

@@ -11608,6 +11608,14 @@ java_complete_lhs (node)
 	  nn = java_complete_tree (build_cast (EXPR_WFL_LINECOL (wfl_op2), 
 					       TREE_TYPE (lvalue), nn));
 
+	  /* If the assignment is compound and has reference type,
+	     then ensure the LHS has type String and nothing else.  */
+	  if (JREFERENCE_TYPE_P (TREE_TYPE (lvalue))
+	      && ! JSTRING_TYPE_P (TREE_TYPE (lvalue)))
+	    parse_error_context (wfl_op2,
+				 "Incompatible type for `+='. Can't convert `%s' to `java.lang.String'",
+				 lang_printable_name (TREE_TYPE (lvalue), 0));
+
 	  /* 15.25.2.b: Left hand is an array access. FIXME */
 	}