diff --git a/src/main/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitor.java b/src/main/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitor.java
index 311b8c3..c7c0eb0 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitor.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitor.java
@@ -77,17 +77,17 @@
 
   public void visit(AbstractComprehension node) {
     for (ListComprehension.Clause clause : node.getClauses()) {
+      visit(clause.getExpression());
       if (clause.getLValue() != null) {
         visit(clause.getLValue());
       }
-      visit(clause.getExpression());
     }
     visitAll(node.getOutputExpressions());
   }
 
   public void visit(ForStatement node) {
-    visit(node.getVariable());
     visit(node.getCollection());
+    visit(node.getVariable());
     visitBlock(node.getBlock());
   }
 
@@ -108,13 +108,13 @@
   }
 
   public void visit(AssignmentStatement node) {
-    visit(node.getLValue());
     visit(node.getExpression());
+    visit(node.getLValue());
   }
 
   public void visit(AugmentedAssignmentStatement node) {
-    visit(node.getLValue());
     visit(node.getExpression());
+    visit(node.getLValue());
   }
 
   public void visit(ExpressionStatement node) {
@@ -183,8 +183,8 @@
   public void visit(@SuppressWarnings("unused") Comment node) {}
 
   public void visit(ConditionalExpression node) {
-    visit(node.getThenCase());
     visit(node.getCondition());
+    visit(node.getThenCase());
     if (node.getElseCase() != null) {
       visit(node.getElseCase());
     }
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitorTest.java b/src/test/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitorTest.java
index 79afdb9..39f46d0 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitorTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/SyntaxTreeVisitorTest.java
@@ -62,7 +62,7 @@
             "  return h + i.j()");
     IdentVisitor visitor = new IdentVisitor();
     ast.accept(visitor);
-    assertThat(idents).containsExactly("a", "b", "c", "d", "e", "f", "g", "h", "i", "j").inOrder();
+    assertThat(idents).containsExactly("b", "a", "c", "e", "d", "f", "g", "h", "i", "j").inOrder();
     assertThat(params).containsExactly("p1", "p2=4", "**p3").inOrder();
   }
 }
diff --git a/src/test/java/com/google/devtools/build/lib/syntax/ValidationTest.java b/src/test/java/com/google/devtools/build/lib/syntax/ValidationTest.java
index 604c53f..49f5dbb 100644
--- a/src/test/java/com/google/devtools/build/lib/syntax/ValidationTest.java
+++ b/src/test/java/com/google/devtools/build/lib/syntax/ValidationTest.java
@@ -105,6 +105,14 @@
   }
 
   @Test
+  public void testDefinitionByItself() throws Exception {
+    checkError("name 'a' is not defined", "a = a");
+    checkError("name 'a' is not defined", "a += a");
+    checkError("name 'a' is not defined", "[[] for a in a]");
+    checkError("name 'a' is not defined", "def f():", "  for a in a: pass");
+  }
+
+  @Test
   public void testLocalValidationEnvironmentsAreSeparated() throws Exception {
     parse("def func1():", "  a = 1", "def func2():", "  a = 'abc'\n");
   }