Make DefaultCase include NullDefaultCase

java/ql/lib/semmle/code/java/Expr.qll

@@ -1535,7 +1535,7 @@ class SwitchExpr extends Expr, StmtParent, @switchexpr {
    *
    * Note this may be `default` or `case null, default`.
    */
-  SwitchCase getDefaultCase() { result = this.getACase() and result.hasDefaultLabel() }
+  DefaultCase getDefaultCase() { result = this.getACase() }
 
   /** Gets the expression of this `switch` expression. */
   Expr getExpr() { result.getParent() = this }
@@ -1738,9 +1738,7 @@ class LocalVariableDeclExpr extends Expr, @localvariabledeclexpr {
 
 /** A local variable declaration that occurs within a record pattern. */
 class RecordBindingVariableExpr extends LocalVariableDeclExpr {
-  RecordBindingVariableExpr() {
-    this.getParent() instanceof RecordPatternExpr
-  }
+  RecordBindingVariableExpr() { this.getParent() instanceof RecordPatternExpr }
 }
 
 /** An update of a variable or an initialization of the variable. */

java/ql/lib/semmle/code/java/Statement.qll

@@ -408,7 +408,7 @@ class SwitchStmt extends Stmt, @switchstmt {
    *
    * Note this may be `default` or `case null, default`.
    */
-  SwitchCase getDefaultCase() { result = this.getACase() and result.hasDefaultLabel() }
+  DefaultCase getDefaultCase() { result = this.getACase() }
 
   /** Gets the expression of this `switch` statement. */
   Expr getExpr() { result.getParent() = this }
@@ -492,12 +492,6 @@ class SwitchCase extends Stmt, @case {
   Stmt getRuleStatementOrExpressionStatement() {
     result.getParent() = this and result.getIndex() = -1
   }
-
-  /**
-   * Holds if this case statement includes the default label, i.e. it is either `default`
-   * or `case null, default`.
-   */
-  predicate hasDefaultLabel() { this instanceof DefaultCase or this instanceof NullDefaultCase }
 }
 
 /**
@@ -553,12 +547,14 @@ class PatternCase extends SwitchCase {
 }
 
 /**
- * A `default` case of a `switch` statement.
- *
- * Note this does not include `case null, default` -- for that, see `NullDefaultCase`.
+ * A `default` or `case null, default` case of a `switch` statement or expression.
  */
 class DefaultCase extends SwitchCase {
-  DefaultCase() { not exists(Expr e | e.getParent() = this | e.getIndex() >= 0) }
+  DefaultCase() {
+    isNullDefaultCase(this)
+    or
+    not exists(Expr e | e.getParent() = this | e.getIndex() >= 0)
+  }
 
   override string pp() { result = "default" }
 
@@ -570,7 +566,7 @@ class DefaultCase extends SwitchCase {
 }
 
 /** A `case null, default` statement of a `switch` statement or expression. */
-class NullDefaultCase extends SwitchCase {
+class NullDefaultCase extends DefaultCase {
   NullDefaultCase() { isNullDefaultCase(this) }
 
   override string pp() { result = "case null, default" }

java/ql/lib/semmle/code/java/controlflow/internal/GuardsLogic.qll

@@ -55,11 +55,11 @@ predicate implies_v1(Guard g1, boolean b1, Guard g2, boolean b2) {
     )
   )
   or
-  exists(SwitchCase sc | g1 = sc and sc.hasDefaultLabel() |
+  exists(DefaultCase sc | g1 = sc |
     sc.getSwitch().getAConstCase() = g2 and b1 = true and b2 = false
   )
   or
-  exists(SwitchCase sc | g1 = sc and sc.hasDefaultLabel() |
+  exists(DefaultCase sc | g1 = sc |
     sc.getSwitchExpr().getAConstCase() = g2 and b1 = true and b2 = false
   )
   or

java/ql/lib/semmle/code/java/metrics/MetricCallable.qll

@@ -78,9 +78,7 @@ private predicate branchingSwitchCase(ConstCase sc) {
 }
 
 private predicate defaultFallThrough(ConstCase sc) {
-  exists(SwitchCase default | default.hasDefaultLabel() |
-    default.(ControlFlowNode).getASuccessor() = sc
-  )
+  exists(DefaultCase default | default.(ControlFlowNode).getASuccessor() = sc)
   or
   defaultFallThrough(sc.(ControlFlowNode).getAPredecessor())
 }