diff --git a/python/ql/lib/semmle/python/controlflow/internal/AstNodeImpl.qll b/python/ql/lib/semmle/python/controlflow/internal/AstNodeImpl.qll
index 212f1c20053..bcf8f4f6470 100644
--- a/python/ql/lib/semmle/python/controlflow/internal/AstNodeImpl.qll
+++ b/python/ql/lib/semmle/python/controlflow/internal/AstNodeImpl.qll
@@ -55,18 +55,18 @@ module Ast implements AstSig<Py::Location> {
 
   private newtype TAstNode =
     TStmt(Py::Stmt s) or
-    TExpr(Py::Expr e) or
+    TExpr(Py::Expr e) { not e instanceof Py::BoolExpr } or
     TScope(Py::Scope sc) or
     TPattern(Py::Pattern p) or
     /**
-     * A synthetic intermediate node in a multi-operand `and`/`or`
+     * A synthetic node representing an operand pair of an `and`/`or`
      * expression. For `a and b and c` (operands 0, 1, 2) we model the
-     * operation as a right-nested tree where the inner pair at index 1
-     * represents `b and c` and is the right operand of the outer pair.
-     * The outermost pair (index 0) is represented by the underlying
-     * `Py::BoolExpr` itself via `TExpr`.
+     * operation as a right-nested tree: pair 0 represents the whole
+     * expression with left=a and right=pair 1; pair 1 represents
+     * `b and c` with left=b and right=c. Each Python `Py::BoolExpr`
+     * with `n` operands has `n - 1` such pairs (indices `0 .. n - 2`).
      */
-    TBoolExprPair(Py::BoolExpr be, int index) { index = [1 .. count(be.getAValue()) - 2] } or
+    TBoolExprPair(Py::BoolExpr be, int index) { index = [0 .. count(be.getAValue()) - 2] } or
     /**
      * A synthetic block statement, identifying one body slot of the
      * `parent` AST node. The `slot` string disambiguates among multiple
@@ -88,8 +88,17 @@ module Ast implements AstSig<Py::Location> {
     /** Gets the underlying Python `Stmt`, if this node wraps one. */
     Py::Stmt asStmt() { this = TStmt(result) }
 
-    /** Gets the underlying Python `Expr`, if this node wraps one. */
-    Py::Expr asExpr() { this = TExpr(result) }
+    /**
+     * Gets the underlying Python `Expr`, if this node wraps one. Boolean
+     * expressions are represented by `TBoolExprPair(_, 0)`; this
+     * predicate also recovers the underlying `Py::BoolExpr` from such a
+     * representation.
+     */
+    Py::Expr asExpr() {
+      this = TExpr(result)
+      or
+      this = TBoolExprPair(result, 0)
+    }
 
     /** Gets the underlying Python `Scope`, if this node wraps one. */
     Py::Scope asScope() { this = TScope(result) }
@@ -105,20 +114,6 @@ module Ast implements AstSig<Py::Location> {
     AstNode getChild(int index) { none() }
   }
 
-  /** Implementation of `AstNode` predicates for synthetic `TBoolExprPair` nodes. */
-  private class BoolExprPair extends Expr, TBoolExprPair {
-    private Py::BoolExpr be;
-    private int index;
-
-    BoolExprPair() { this = TBoolExprPair(be, index) }
-
-    override string toString() { result = be.getOperator() }
-
-    override Py::Location getLocation() { result = be.getValue(index).getLocation() }
-
-    override Callable getEnclosingCallable() { result.asScope() = be.getScope() }
-  }
-
   /** Gets the immediately enclosing callable that contains `node`. */
   Callable getEnclosingCallable(AstNode node) { result = node.getEnclosingCallable() }
 
@@ -174,7 +169,7 @@ module Ast implements AstSig<Py::Location> {
     Expr() { this instanceof TExpr or this instanceof TBoolExprPair }
 
     // For `TExpr` instances, delegate to the wrapped Python expression.
-    // `BoolExprPair` (the only `TBoolExprPair` subclass) provides its own overrides.
+    // `BinaryExpr` (the only `TBoolExprPair` subclass) provides its own overrides.
     override string toString() { result = this.asExpr().toString() }
 
     override Py::Location getLocation() { result = this.asExpr().getLocation() }
@@ -235,7 +230,7 @@ module Ast implements AstSig<Py::Location> {
     ExprStmt() { exprStmt = this.asStmt() }
 
     /** Gets the expression in this expression statement. */
-    Expr getExpr() { result = TExpr(exprStmt.getValue()) }
+    Expr getExpr() { result.asExpr() = exprStmt.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getExpr() }
   }
@@ -246,9 +241,9 @@ module Ast implements AstSig<Py::Location> {
 
     AssignStmt() { assign = this.asStmt() }
 
-    Expr getValue() { result = TExpr(assign.getValue()) }
+    Expr getValue() { result.asExpr() = assign.getValue() }
 
-    Expr getTarget(int n) { result = TExpr(assign.getTarget(n)) }
+    Expr getTarget(int n) { result.asExpr() = assign.getTarget(n) }
 
     int getNumberOfTargets() { result = count(assign.getATarget()) }
 
@@ -265,7 +260,7 @@ module Ast implements AstSig<Py::Location> {
 
     AugAssignStmt() { augAssign = this.asStmt() }
 
-    Expr getOperation() { result = TExpr(augAssign.getOperation()) }
+    Expr getOperation() { result.asExpr() = augAssign.getOperation() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getOperation() }
   }
@@ -276,9 +271,9 @@ module Ast implements AstSig<Py::Location> {
 
     NamedExpr() { assignExpr = this.asExpr() }
 
-    Expr getValue() { result = TExpr(assignExpr.getValue()) }
+    Expr getValue() { result.asExpr() = assignExpr.getValue() }
 
-    Expr getTarget() { result = TExpr(assignExpr.getTarget()) }
+    Expr getTarget() { result.asExpr() = assignExpr.getTarget() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getValue()
@@ -305,7 +300,7 @@ module Ast implements AstSig<Py::Location> {
     Py::If asIf() { result = ifStmt }
 
     /** Gets the condition of this `if` statement. */
-    Expr getCondition() { result = TExpr(ifStmt.getTest()) }
+    Expr getCondition() { result.asExpr() = ifStmt.getTest() }
 
     /** Gets the `then` (true) branch of this `if` statement. */
     Stmt getThen() { result = TBlockStmt(ifStmt, "body") }
@@ -337,7 +332,7 @@ module Ast implements AstSig<Py::Location> {
     WhileStmt() { whileStmt = this.asStmt() }
 
     /** Gets the boolean condition of this `while` loop. */
-    Expr getCondition() { result = TExpr(whileStmt.getTest()) }
+    Expr getCondition() { result.asExpr() = whileStmt.getTest() }
 
     override Stmt getBody() { result = TBlockStmt(whileStmt, "body") }
 
@@ -380,10 +375,10 @@ module Ast implements AstSig<Py::Location> {
     ForeachStmt() { forStmt = this.asStmt() }
 
     /** Gets the loop variable. */
-    Expr getVariable() { result = TExpr(forStmt.getTarget()) }
+    Expr getVariable() { result.asExpr() = forStmt.getTarget() }
 
     /** Gets the collection being iterated. */
-    Expr getCollection() { result = TExpr(forStmt.getIter()) }
+    Expr getCollection() { result.asExpr() = forStmt.getIter() }
 
     override Stmt getBody() { result = TBlockStmt(forStmt, "body") }
 
@@ -423,7 +418,7 @@ module Ast implements AstSig<Py::Location> {
     ReturnStmt() { ret = this.asStmt() }
 
     /** Gets the expression being returned, if any. */
-    Expr getExpr() { result = TExpr(ret.getValue()) }
+    Expr getExpr() { result.asExpr() = ret.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getExpr() }
   }
@@ -435,10 +430,10 @@ module Ast implements AstSig<Py::Location> {
     Throw() { raise = this.asStmt() }
 
     /** Gets the expression being raised. */
-    Expr getExpr() { result = TExpr(raise.getException()) }
+    Expr getExpr() { result.asExpr() = raise.getException() }
 
     /** Gets the cause of this `raise`, if any. */
-    Expr getCause() { result = TExpr(raise.getCause()) }
+    Expr getCause() { result.asExpr() = raise.getCause() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getExpr()
@@ -453,9 +448,9 @@ module Ast implements AstSig<Py::Location> {
 
     WithStmt() { withStmt = this.asStmt() }
 
-    Expr getContextExpr() { result = TExpr(withStmt.getContextExpr()) }
+    Expr getContextExpr() { result.asExpr() = withStmt.getContextExpr() }
 
-    Expr getOptionalVars() { result = TExpr(withStmt.getOptionalVars()) }
+    Expr getOptionalVars() { result.asExpr() = withStmt.getOptionalVars() }
 
     Stmt getBody() { result = TBlockStmt(withStmt, "body") }
 
@@ -474,9 +469,9 @@ module Ast implements AstSig<Py::Location> {
 
     AssertStmt() { assertStmt = this.asStmt() }
 
-    Expr getTest() { result = TExpr(assertStmt.getTest()) }
+    Expr getTest() { result.asExpr() = assertStmt.getTest() }
 
-    Expr getMsg() { result = TExpr(assertStmt.getMsg()) }
+    Expr getMsg() { result.asExpr() = assertStmt.getMsg() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getTest()
@@ -491,7 +486,7 @@ module Ast implements AstSig<Py::Location> {
 
     DeleteStmt() { del = this.asStmt() }
 
-    Expr getTarget(int n) { result = TExpr(del.getTarget(n)) }
+    Expr getTarget(int n) { result.asExpr() = del.getTarget(n) }
 
     override AstNode getChild(int index) { result = this.getTarget(index) }
   }
@@ -544,10 +539,10 @@ module Ast implements AstSig<Py::Location> {
     CatchClause() { handler = this.asStmt() }
 
     /** Gets the type expression of this exception handler. */
-    Expr getType() { result = TExpr(handler.getType()) }
+    Expr getType() { result.asExpr() = handler.getType() }
 
     /** Gets the variable name of this exception handler, if any. */
-    AstNode getVariable() { result = TExpr(handler.getName()) }
+    AstNode getVariable() { result.asExpr() = handler.getName() }
 
     /** Holds: catch clauses do not have a `Condition` in Python's model. */
     Expr getCondition() { none() }
@@ -574,7 +569,7 @@ module Ast implements AstSig<Py::Location> {
 
     Switch() { matchStmt = this.asStmt() }
 
-    Expr getExpr() { result = TExpr(matchStmt.getSubject()) }
+    Expr getExpr() { result.asExpr() = matchStmt.getSubject() }
 
     Case getCase(int index) { result = TStmt(matchStmt.getCase(index)) }
 
@@ -595,7 +590,7 @@ module Ast implements AstSig<Py::Location> {
 
     AstNode getAPattern() { result = TPattern(caseStmt.getPattern()) }
 
-    Expr getGuard() { result = TExpr(caseStmt.getGuard().(Py::Guard).getTest()) }
+    Expr getGuard() { result.asExpr() = caseStmt.getGuard().(Py::Guard).getTest() }
 
     AstNode getBody() { result = TBlockStmt(caseStmt, "body") }
 
@@ -623,13 +618,13 @@ module Ast implements AstSig<Py::Location> {
     ConditionalExpr() { ifExp = this.asExpr() }
 
     /** Gets the condition of this expression. */
-    Expr getCondition() { result = TExpr(ifExp.getTest()) }
+    Expr getCondition() { result.asExpr() = ifExp.getTest() }
 
     /** Gets the true branch of this expression. */
-    Expr getThen() { result = TExpr(ifExp.getBody()) }
+    Expr getThen() { result.asExpr() = ifExp.getBody() }
 
     /** Gets the false branch of this expression. */
-    Expr getElse() { result = TExpr(ifExp.getOrelse()) }
+    Expr getElse() { result.asExpr() = ifExp.getOrelse() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getCondition()
@@ -641,84 +636,51 @@ module Ast implements AstSig<Py::Location> {
   }
 
   /**
-   * A binary expression for the shared CFG. In Python, this covers
-   * `and`/`or` expressions (both real 2-operand and synthetic pairs).
+   * A binary expression for the shared CFG. In Python, this covers all
+   * `and`/`or` expression operand pairs.
    */
-  class BinaryExpr extends Expr {
-    BinaryExpr() {
-      exists(Py::BoolExpr be | this = TExpr(be) and count(be.getAValue()) >= 2)
-      or
-      this instanceof TBoolExprPair
-    }
+  class BinaryExpr extends Expr, TBoolExprPair {
+    private Py::BoolExpr be;
+    private int index;
+
+    BinaryExpr() { this = TBoolExprPair(be, index) }
+
+    /** Gets the underlying Python `BoolExpr`. */
+    Py::BoolExpr getBoolExpr() { result = be }
+
+    override string toString() { result = be.getOperator() }
+
+    override Py::Location getLocation() { result = be.getValue(index).getLocation() }
+
+    override Callable getEnclosingCallable() { result.asScope() = be.getScope() }
 
     /** Gets the left operand of this binary expression. */
-    Expr getLeftOperand() {
-      exists(Py::BoolExpr be | this = TExpr(be) and result = TExpr(be.getValue(0)))
-      or
-      exists(Py::BoolExpr be, int i |
-        this = TBoolExprPair(be, i) and result = TExpr(be.getValue(i))
-      )
-    }
+    Expr getLeftOperand() { result.asExpr() = be.getValue(index) }
 
     /** Gets the right operand of this binary expression. */
     Expr getRightOperand() {
-      // 2-operand BoolExpr: right operand is value(1).
-      exists(Py::BoolExpr be |
-        this = TExpr(be) and
-        count(be.getAValue()) = 2 and
-        result = TExpr(be.getValue(1))
-      )
+      // Last pair: right operand is the final value.
+      index = count(be.getAValue()) - 2 and result.asExpr() = be.getValue(index + 1)
       or
-      // 3+ operand BoolExpr (outermost): right operand is the synthetic
-      // pair at index 1.
-      exists(Py::BoolExpr be |
-        this = TExpr(be) and
-        count(be.getAValue()) > 2 and
-        result = TBoolExprPair(be, 1)
-      )
-      or
-      // Last synthetic pair: right operand is the final value.
-      exists(Py::BoolExpr be, int i, int n |
-        this = TBoolExprPair(be, i) and
-        n = count(be.getAValue()) and
-        i = n - 2 and
-        result = TExpr(be.getValue(i + 1))
-      )
-      or
-      // Non-last synthetic pair: right operand is the next pair.
-      exists(Py::BoolExpr be, int i, int n |
-        this = TBoolExprPair(be, i) and
-        n = count(be.getAValue()) and
-        i < n - 2 and
-        result = TBoolExprPair(be, i + 1)
-      )
+      // Non-last pair: right operand is the next synthetic pair.
+      index < count(be.getAValue()) - 2 and result = TBoolExprPair(be, index + 1)
     }
 
-    override AstNode getChild(int index) {
-      index = 0 and result = this.getLeftOperand()
+    override AstNode getChild(int childIndex) {
+      childIndex = 0 and result = this.getLeftOperand()
       or
-      index = 1 and result = this.getRightOperand()
+      childIndex = 1 and result = this.getRightOperand()
     }
   }
 
   /** A short-circuiting logical `and` expression. */
   class LogicalAndExpr extends BinaryExpr {
-    LogicalAndExpr() {
-      exists(Py::BoolExpr be |
-        be.getOp() instanceof Py::And and
-        (this = TExpr(be) or this = TBoolExprPair(be, _))
-      )
-    }
+    LogicalAndExpr() { this.getBoolExpr().getOp() instanceof Py::And }
   }
 
   /** A short-circuiting logical `or` expression. */
   class LogicalOrExpr extends BinaryExpr {
-    LogicalOrExpr() {
-      exists(Py::BoolExpr be |
-        be.getOp() instanceof Py::Or and
-        (this = TExpr(be) or this = TBoolExprPair(be, _))
-      )
-    }
+    LogicalOrExpr() { this.getBoolExpr().getOp() instanceof Py::Or }
   }
 
   /** A null-coalescing expression. Python has no null-coalescing operator. */
@@ -733,7 +695,7 @@ module Ast implements AstSig<Py::Location> {
     UnaryExpr() { this.asExpr().(Py::UnaryExpr).getOp() instanceof Py::Not }
 
     /** Gets the operand of this unary expression. */
-    Expr getOperand() { result = TExpr(this.asExpr().(Py::UnaryExpr).getOperand()) }
+    Expr getOperand() { result.asExpr() = this.asExpr().(Py::UnaryExpr).getOperand() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getOperand() }
   }
@@ -784,9 +746,9 @@ module Ast implements AstSig<Py::Location> {
 
     ArithBinaryExpr() { binExpr = this.asExpr() }
 
-    Expr getLeft() { result = TExpr(binExpr.getLeft()) }
+    Expr getLeft() { result.asExpr() = binExpr.getLeft() }
 
-    Expr getRight() { result = TExpr(binExpr.getRight()) }
+    Expr getRight() { result.asExpr() = binExpr.getRight() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getLeft()
@@ -801,16 +763,16 @@ module Ast implements AstSig<Py::Location> {
 
     CallExpr() { call = this.asExpr() }
 
-    Expr getFunc() { result = TExpr(call.getFunc()) }
+    Expr getFunc() { result.asExpr() = call.getFunc() }
 
-    Expr getPositionalArg(int n) { result = TExpr(call.getPositionalArg(n)) }
+    Expr getPositionalArg(int n) { result.asExpr() = call.getPositionalArg(n) }
 
     int getNumberOfPositionalArgs() { result = count(call.getAPositionalArg()) }
 
     Expr getKeywordValue(int n) {
-      result = TExpr(call.getNamedArg(n).(Py::Keyword).getValue())
+      result.asExpr() = call.getNamedArg(n).(Py::Keyword).getValue()
       or
-      result = TExpr(call.getNamedArg(n).(Py::DictUnpacking).getValue())
+      result.asExpr() = call.getNamedArg(n).(Py::DictUnpacking).getValue()
     }
 
     int getNumberOfNamedArgs() { result = count(call.getANamedArg()) }
@@ -831,9 +793,9 @@ module Ast implements AstSig<Py::Location> {
 
     SubscriptExpr() { sub = this.asExpr() }
 
-    Expr getObject() { result = TExpr(sub.getObject()) }
+    Expr getObject() { result.asExpr() = sub.getObject() }
 
-    Expr getIndex() { result = TExpr(sub.getIndex()) }
+    Expr getIndex() { result.asExpr() = sub.getIndex() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getObject()
@@ -848,7 +810,7 @@ module Ast implements AstSig<Py::Location> {
 
     AttributeExpr() { attr = this.asExpr() }
 
-    Expr getObject() { result = TExpr(attr.getObject()) }
+    Expr getObject() { result.asExpr() = attr.getObject() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getObject() }
   }
@@ -859,7 +821,7 @@ module Ast implements AstSig<Py::Location> {
 
     TupleExpr() { tuple = this.asExpr() }
 
-    Expr getElt(int n) { result = TExpr(tuple.getElt(n)) }
+    Expr getElt(int n) { result.asExpr() = tuple.getElt(n) }
 
     override AstNode getChild(int index) { result = this.getElt(index) }
   }
@@ -870,7 +832,7 @@ module Ast implements AstSig<Py::Location> {
 
     ListExpr() { list = this.asExpr() }
 
-    Expr getElt(int n) { result = TExpr(list.getElt(n)) }
+    Expr getElt(int n) { result.asExpr() = list.getElt(n) }
 
     override AstNode getChild(int index) { result = this.getElt(index) }
   }
@@ -881,7 +843,7 @@ module Ast implements AstSig<Py::Location> {
 
     SetExpr() { set = this.asExpr() }
 
-    Expr getElt(int n) { result = TExpr(set.getElt(n)) }
+    Expr getElt(int n) { result.asExpr() = set.getElt(n) }
 
     override AstNode getChild(int index) { result = this.getElt(index) }
   }
@@ -896,9 +858,9 @@ module Ast implements AstSig<Py::Location> {
      * Gets the key of the `n`th item (at child index `2*n`); the value is
      * at child index `2*n + 1`.
      */
-    Expr getKey(int n) { result = TExpr(dict.getItem(n).(Py::KeyValuePair).getKey()) }
+    Expr getKey(int n) { result.asExpr() = dict.getItem(n).(Py::KeyValuePair).getKey() }
 
-    Expr getValue(int n) { result = TExpr(dict.getItem(n).(Py::KeyValuePair).getValue()) }
+    Expr getValue(int n) { result.asExpr() = dict.getItem(n).(Py::KeyValuePair).getValue() }
 
     int getNumberOfItems() { result = count(dict.getAnItem()) }
 
@@ -917,7 +879,7 @@ module Ast implements AstSig<Py::Location> {
 
     ArithUnaryExpr() { unaryExpr = this.asExpr() and not unaryExpr.getOp() instanceof Py::Not }
 
-    Expr getOperand() { result = TExpr(unaryExpr.getOperand()) }
+    Expr getOperand() { result.asExpr() = unaryExpr.getOperand() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getOperand() }
   }
@@ -940,7 +902,7 @@ module Ast implements AstSig<Py::Location> {
       iterable = this.asExpr().(Py::GeneratorExp).getIterable()
     }
 
-    Expr getIterable() { result = TExpr(iterable) }
+    Expr getIterable() { result.asExpr() = iterable }
 
     override AstNode getChild(int index) { index = 0 and result = this.getIterable() }
   }
@@ -951,9 +913,9 @@ module Ast implements AstSig<Py::Location> {
 
     CompareExpr() { cmp = this.asExpr() }
 
-    Expr getLeft() { result = TExpr(cmp.getLeft()) }
+    Expr getLeft() { result.asExpr() = cmp.getLeft() }
 
-    Expr getComparator(int n) { result = TExpr(cmp.getComparator(n)) }
+    Expr getComparator(int n) { result.asExpr() = cmp.getComparator(n) }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getLeft()
@@ -968,11 +930,11 @@ module Ast implements AstSig<Py::Location> {
 
     SliceExpr() { slice = this.asExpr() }
 
-    Expr getStart() { result = TExpr(slice.getStart()) }
+    Expr getStart() { result.asExpr() = slice.getStart() }
 
-    Expr getStop() { result = TExpr(slice.getStop()) }
+    Expr getStop() { result.asExpr() = slice.getStop() }
 
-    Expr getStep() { result = TExpr(slice.getStep()) }
+    Expr getStep() { result.asExpr() = slice.getStep() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getStart()
@@ -989,7 +951,7 @@ module Ast implements AstSig<Py::Location> {
 
     StarredExpr() { starred = this.asExpr() }
 
-    Expr getValue() { result = TExpr(starred.getValue()) }
+    Expr getValue() { result.asExpr() = starred.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getValue() }
   }
@@ -1000,7 +962,7 @@ module Ast implements AstSig<Py::Location> {
 
     FstringExpr() { fstring = this.asExpr() }
 
-    Expr getValue(int n) { result = TExpr(fstring.getValue(n)) }
+    Expr getValue(int n) { result.asExpr() = fstring.getValue(n) }
 
     override AstNode getChild(int index) { result = this.getValue(index) }
   }
@@ -1011,9 +973,9 @@ module Ast implements AstSig<Py::Location> {
 
     FormattedValueExpr() { fv = this.asExpr() }
 
-    Expr getValue() { result = TExpr(fv.getValue()) }
+    Expr getValue() { result.asExpr() = fv.getValue() }
 
-    Expr getFormatSpec() { result = TExpr(fv.getFormatSpec()) }
+    Expr getFormatSpec() { result.asExpr() = fv.getFormatSpec() }
 
     override AstNode getChild(int index) {
       index = 0 and result = this.getValue()
@@ -1028,7 +990,7 @@ module Ast implements AstSig<Py::Location> {
 
     YieldExpr() { yield = this.asExpr() }
 
-    Expr getValue() { result = TExpr(yield.getValue()) }
+    Expr getValue() { result.asExpr() = yield.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getValue() }
   }
@@ -1039,7 +1001,7 @@ module Ast implements AstSig<Py::Location> {
 
     YieldFromExpr() { yieldFrom = this.asExpr() }
 
-    Expr getValue() { result = TExpr(yieldFrom.getValue()) }
+    Expr getValue() { result.asExpr() = yieldFrom.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getValue() }
   }
@@ -1050,7 +1012,7 @@ module Ast implements AstSig<Py::Location> {
 
     AwaitExpr() { await = this.asExpr() }
 
-    Expr getValue() { result = TExpr(await.getValue()) }
+    Expr getValue() { result.asExpr() = await.getValue() }
 
     override AstNode getChild(int index) { index = 0 and result = this.getValue() }
   }
@@ -1061,7 +1023,7 @@ module Ast implements AstSig<Py::Location> {
 
     ClassDefExpr() { classExpr = this.asExpr() }
 
-    Expr getBase(int n) { result = TExpr(classExpr.getBase(n)) }
+    Expr getBase(int n) { result.asExpr() = classExpr.getBase(n) }
 
     override AstNode getChild(int index) { result = this.getBase(index) }
   }
@@ -1079,14 +1041,14 @@ module Ast implements AstSig<Py::Location> {
      * renumber here to obtain contiguous indices.
      */
     Expr getDefault(int n) {
-      result =
-        TExpr(rank[n + 1](Py::Expr d, int i | d = funcExpr.getArgs().getDefault(i) | d order by i))
+      result.asExpr() =
+        rank[n + 1](Py::Expr d, int i | d = funcExpr.getArgs().getDefault(i) | d order by i)
     }
 
     /** Gets the `n`th default for a keyword-only argument, in evaluation order. */
     Expr getKwDefault(int n) {
-      result =
-        TExpr(rank[n + 1](Py::Expr d, int i | d = funcExpr.getArgs().getKwDefault(i) | d order by i))
+      result.asExpr() =
+        rank[n + 1](Py::Expr d, int i | d = funcExpr.getArgs().getKwDefault(i) | d order by i)
     }
 
     int getNumberOfDefaults() { result = count(funcExpr.getArgs().getADefault()) }
@@ -1106,14 +1068,14 @@ module Ast implements AstSig<Py::Location> {
 
     /** Gets the `n`th default for a positional argument, in evaluation order. */
     Expr getDefault(int n) {
-      result =
-        TExpr(rank[n + 1](Py::Expr d, int i | d = lambda.getArgs().getDefault(i) | d order by i))
+      result.asExpr() =
+        rank[n + 1](Py::Expr d, int i | d = lambda.getArgs().getDefault(i) | d order by i)
     }
 
     /** Gets the `n`th default for a keyword-only argument, in evaluation order. */
     Expr getKwDefault(int n) {
-      result =
-        TExpr(rank[n + 1](Py::Expr d, int i | d = lambda.getArgs().getKwDefault(i) | d order by i))
+      result.asExpr() =
+        rank[n + 1](Py::Expr d, int i | d = lambda.getArgs().getKwDefault(i) | d order by i)
     }
 
     int getNumberOfDefaults() { result = count(lambda.getArgs().getADefault()) }