diff --git a/java/ql/lib/semmle/code/java/dataflow/Nullness.qll b/java/ql/lib/semmle/code/java/dataflow/Nullness.qll
index 786207d3486..36ad96c497f 100644
--- a/java/ql/lib/semmle/code/java/dataflow/Nullness.qll
+++ b/java/ql/lib/semmle/code/java/dataflow/Nullness.qll
@@ -141,8 +141,6 @@ private ControlFlowNode varDereference(SsaVariable v, VarAccess va) {
 private ControlFlowNode ensureNotNull(SsaVariable v) {
   result = varDereference(v, _)
   or
-  result.asStmt().(AssertStmt).getExpr() = nullGuard(v, true, false)
-  or
   exists(AssertTrueMethod m | result.asCall() = m.getACheck(nullGuard(v, true, false)))
   or
   exists(AssertFalseMethod m | result.asCall() = m.getACheck(nullGuard(v, false, false)))
diff --git a/java/ql/lib/semmle/code/java/frameworks/Assertions.qll b/java/ql/lib/semmle/code/java/frameworks/Assertions.qll
index e7f86b9bfd8..e1601c854e4 100644
--- a/java/ql/lib/semmle/code/java/frameworks/Assertions.qll
+++ b/java/ql/lib/semmle/code/java/frameworks/Assertions.qll
@@ -110,11 +110,17 @@ predicate assertFail(BasicBlock bb, ControlFlowNode n) {
   (
     exists(AssertTrueMethod m |
       n.asExpr() = m.getACheck(any(BooleanLiteral b | b.getBooleanValue() = false))
-    ) or
+    )
+    or
     exists(AssertFalseMethod m |
       n.asExpr() = m.getACheck(any(BooleanLiteral b | b.getBooleanValue() = true))
-    ) or
-    exists(AssertFailMethod m | n.asExpr() = m.getACheck()) or
-    n.asStmt().(AssertStmt).getExpr().(BooleanLiteral).getBooleanValue() = false
+    )
+    or
+    exists(AssertFailMethod m | n.asExpr() = m.getACheck())
+    or
+    exists(AssertStmt a |
+      n.asExpr() = a.getExpr() and
+      a.getExpr().(BooleanLiteral).getBooleanValue() = false
+    )
   )
 }