Basic extraction of record patterns

java/ql/lib/config/semmlecode.dbscheme

@@ -774,6 +774,7 @@ case @expr.kind of
 | 86  = @valueeqexpr
 | 87  = @valueneexpr
 | 88  = @propertyref
+| 89  = @recordpatternexpr
 ;
 
 /** Holds if this `when` expression was written as an `if` expression. */

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

@@ -529,7 +529,7 @@ private module ControlFlowGraphImpl {
       or
       this instanceof LocalVariableDeclExpr and
       not this = any(InstanceOfExpr ioe).getLocalVariableDeclExpr() and
-      not this = any(PatternCase pc).getDecl()
+      not this = any(PatternCase pc).getPattern()
       or
       this instanceof StringTemplateExpr
       or
@@ -971,7 +971,7 @@ private module ControlFlowGraphImpl {
       (
         if exists(pc.getGuard())
         then last(pc.getGuard(), last, BooleanCompletion(true, _))
-        else last = pc.getDecl()
+        else last = pc.getPattern()
       ) and
       not pc.isRule() and
       completion = NormalCompletion()
@@ -1332,7 +1332,7 @@ private module ControlFlowGraphImpl {
           last(case.(PatternCase).getGuard(), preBodyNode, completion) and
           completion = basicBooleanCompletion(true)
         ) else (
-          preBodyNode = case.(PatternCase).getDecl() and completion = NormalCompletion()
+          preBodyNode = case.(PatternCase).getPattern() and completion = NormalCompletion()
         )
       ) else (
         preBodyNode = case and completion = NormalCompletion()
@@ -1351,7 +1351,7 @@ private module ControlFlowGraphImpl {
         result = getASuccessorSwitchCase(case)
         or
         completion = basicBooleanCompletion(true) and
-        result = case.getDecl()
+        result = case.getPattern()
       )
     )
     or
@@ -1362,7 +1362,7 @@ private module ControlFlowGraphImpl {
     exists(PatternCase case, Expr guard |
       guard = case.getGuard() and
       (
-        n = case.getDecl() and
+        n = case.getPattern() and
         result = first(guard) and
         completion = NormalCompletion()
         or

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

@@ -82,7 +82,7 @@ predicate depends(RefType t, RefType dep) {
     or
     // the type accessed in a pattern-switch case statement in `t`.
     exists(PatternCase pc | t = pc.getEnclosingCallable().getDeclaringType() |
-      usesType(pc.getDecl().getType(), dep)
+      usesType(pc.getPattern().getType(), dep)
     )
   )
 }

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

@@ -2541,3 +2541,10 @@ class NotNullExpr extends UnaryExpr, @notnullexpr {
 
   override string getAPrimaryQlClass() { result = "NotNullExpr" }
 }
+
+/** A record pattern expr, as in `if (x instanceof SomeRecord(int field))`. */
+class RecordPatternExpr extends Expr, @recordpatternexpr {
+  override string toString() { result = this.getType().toString() + "(...)" }
+
+  override string getAPrimaryQlClass() { result = "RecordPatternExpr" }
+}

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

@@ -507,7 +507,7 @@ class SwitchCase extends Stmt, @case {
 class ConstCase extends SwitchCase {
   ConstCase() {
     exists(Expr e |
-      e.getParent() = this and e.getIndex() >= 0 and not e instanceof LocalVariableDeclExpr
+      e.getParent() = this and e.getIndex() >= 0 and not e instanceof Pattern
     )
     // For backward compatibility, we don't include `case null, default:` here, on the assumption
     // this will come as a surprise to CodeQL that predates that statement's validity.
@@ -531,14 +531,35 @@ class ConstCase extends SwitchCase {
   override string getAPrimaryQlClass() { result = "ConstCase" }
 }
 
+/**
+ * A binding or record pattern.
+ *
+ * Note binding patterns are represented as `LocalVariableDeclExpr`s.
+ */
+class Pattern extends Expr {
+  Pattern() {
+    (this.getParent() instanceof SwitchCase or this.getParent() instanceof InstanceOfExpr)
+    and
+    (this instanceof LocalVariableDeclExpr or this instanceof RecordPatternExpr)
+  }
+
+  LocalVariableDeclExpr asBindingPattern() {
+    result = this
+  }
+
+  RecordPatternExpr asRecordPattern() {
+    result = this
+  }
+}
+
 /** A pattern case of a `switch` statement */
 class PatternCase extends SwitchCase {
-  LocalVariableDeclExpr patternVar;
+  Pattern pattern;
 
-  PatternCase() { patternVar.isNthChildOf(this, 0) }
+  PatternCase() { pattern.isNthChildOf(this, 0) }
 
-  /** Gets the variable declared by this pattern case. */
-  LocalVariableDeclExpr getDecl() { result.isNthChildOf(this, 0) }
+  /** Gets this case's pattern. */
+  Pattern getPattern() { result.isNthChildOf(this, 0) }
 
   /** Gets the guard applicable to this pattern case, if any. */
   Expr getGuard() { result.isNthChildOf(this, -3) }

java/ql/lib/semmle/code/java/controlflow/Guards.qll

@@ -180,7 +180,7 @@ private predicate switchCaseControls(SwitchCase sc, BasicBlock bb) {
     selector = sc.getSelectorExpr() and
     (
       if sc instanceof PatternCase
-      then caseblock.getFirstNode() = sc.(PatternCase).getDecl().getControlFlowNode()
+      then caseblock.getFirstNode() = sc.(PatternCase).getPattern().getControlFlowNode()
       else (
         caseblock.getFirstNode() = sc.getControlFlowNode() and
         // Check there is no fall-through edge from a previous case:

java/ql/lib/semmle/code/java/dataflow/TypeFlow.qll

@@ -447,7 +447,7 @@ private predicate patternCaseGuarded(Expr e, RefType t) {
   exists(PatternCase pc |
     e = getAProbableAlias([pc.getSwitch().getExpr(), pc.getSwitchExpr().getExpr()]) and
     guardControls_v1(pc, e.getBasicBlock(), true) and
-    t = pc.getDecl().getType()
+    t = pc.getPattern().getType()
   )
 }
 

java/ql/lib/semmle/code/java/dispatch/ObjFlow.qll

@@ -82,7 +82,7 @@ private predicate step(Node n1, Node n2) {
     )
     or
     exists(PatternCase pc |
-      pc.getDecl() = def.(BaseSsaUpdate).getDefiningExpr() and
+      pc.getPattern() = def.(BaseSsaUpdate).getDefiningExpr() and
       (
         pc.getSwitch().getExpr() = n1.asExpr()
         or