Java: Add ErrorExpr, ErrorStmt

Author: igfoo

java/ql/lib/config/semmlecode.dbscheme

@@ -528,6 +528,7 @@ case @stmt.kind of
 | 21 = @case
 | 22 = @catchclause
 | 23 = @yieldstmt
+| 24 = @errorstmt
 ;
 
 #keyset[parent,idx]
@@ -628,6 +629,7 @@ case @expr.kind of
 | 71  = @typeannotation
 | 72  = @intersectiontypeaccess
 | 73  = @switchexpr
+| 74  = @errorexpr
 ;
 
 @classinstancexpr = @newexpr | @lambdaexpr | @memberref

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

@@ -377,6 +377,18 @@ class CompileTimeConstantExpr extends Expr {
 /** An expression parent is an element that may have an expression as its child. */
 class ExprParent extends @exprparent, Top { }
 
+/**
+ * An error expression.
+ *
+ * These may be generated by upgrade or downgrade scripts when databases
+ * cannot be fully converted.
+ */
+class ErrorExpr extends Expr, @errorexpr {
+  override string toString() { result = "<error expr>" }
+
+  override string getAPrimaryQlClass() { result = "ErrorExpr" }
+}
+
 /**
  * An array access.
  *

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

@@ -59,6 +59,18 @@ class Stmt extends StmtParent, ExprParent, @stmt {
 /** A statement parent is any element that can have a statement as its child. */
 class StmtParent extends @stmtparent, Top { }
 
+/**
+ * An error statement.
+ *
+ * These may be generated by upgrade or downgrade scripts when databases
+ * cannot be fully converted.
+ */
+class ErrorStmt extends Stmt, @errorstmt {
+  override string toString() { result = "<error stmt>" }
+
+  override string getAPrimaryQlClass() { result = "ErrorStmt" }
+}
+
 /** A block of statements. */
 class BlockStmt extends Stmt, @block {
   /** Gets a statement that is an immediate child of this block. */