From 8662f0d0c251995f904b09032777d78a2a75129b Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 11 Feb 2026 00:15:51 +0000
Subject: [PATCH 1/2] Initial plan


From d29f71590bc83e904279ff6ae2c7a56a25110b0c Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Wed, 11 Feb 2026 01:02:21 +0000
Subject: [PATCH 2/2] Port TypeScript PR #63026: Fix crash from
 circularly-reentrant getEffectsSignature

Add PropagatesThisKeyword container flag and seenThisKeyword save/restore
logic in IsControlFlowContainer branch to prevent infinite recursion when
typeof queries in function-like type nodes trigger getEffectsSignature.

Co-authored-by: jakebailey <5341706+jakebailey@users.noreply.github.com>
---
 internal/binder/binder.go | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/internal/binder/binder.go b/internal/binder/binder.go
index f44ff210738..99f542474b1 100644
--- a/internal/binder/binder.go
+++ b/internal/binder/binder.go
@@ -39,6 +39,7 @@ const (
 	ContainerFlagsIsInterface                                      ContainerFlags = 1 << 6
 	ContainerFlagsIsObjectLiteralOrClassExpressionMethodOrAccessor ContainerFlags = 1 << 7
 	ContainerFlagsIsThisContainer                                  ContainerFlags = 1 << 8
+	ContainerFlagsPropagatesThisKeyword                            ContainerFlags = 1 << 9
 )
 
 type ExpandoAssignmentInfo struct {
@@ -1520,6 +1521,7 @@ func (b *Binder) bindContainer(node *ast.Node, containerFlags ContainerFlags) {
 		saveExceptionTarget := b.currentExceptionTarget
 		saveActiveLabelList := b.activeLabelList
 		saveHasExplicitReturn := b.hasExplicitReturn
+		saveSeenThisKeyword := b.seenThisKeyword
 		isImmediatelyInvoked := (containerFlags&ContainerFlagsIsFunctionExpression != 0 &&
 			!ast.HasSyntacticModifier(node, ast.ModifierFlagsAsync) &&
 			!isGeneratorFunctionExpression(node) &&
@@ -1545,9 +1547,10 @@ func (b *Binder) bindContainer(node *ast.Node, containerFlags ContainerFlags) {
 		b.currentContinueTarget = nil
 		b.activeLabelList = nil
 		b.hasExplicitReturn = false
+		b.seenThisKeyword = false
 		b.bindChildren(node)
 		// Reset all reachability check related flags on node (for incremental scenarios)
-		node.Flags &= ^ast.NodeFlagsReachabilityCheckFlags
+		node.Flags &= ^(ast.NodeFlagsReachabilityCheckFlags | ast.NodeFlagsContainsThis)
 		if b.currentFlow.Flags&ast.FlowFlagsUnreachable == 0 && containerFlags&ContainerFlagsIsFunctionLike != 0 {
 			bodyData := node.BodyData()
 			if bodyData != nil && ast.NodeIsPresent(bodyData.Body) {
@@ -1558,6 +1561,9 @@ func (b *Binder) bindContainer(node *ast.Node, containerFlags ContainerFlags) {
 				bodyData.EndFlowNode = b.currentFlow
 			}
 		}
+		if b.seenThisKeyword {
+			node.Flags |= ast.NodeFlagsContainsThis
+		}
 		if node.Kind == ast.KindSourceFile {
 			node.Flags |= b.emitFlags
 			node.AsSourceFile().EndFlowNode = b.currentFlow
@@ -1579,6 +1585,11 @@ func (b *Binder) bindContainer(node *ast.Node, containerFlags ContainerFlags) {
 		b.currentExceptionTarget = saveExceptionTarget
 		b.activeLabelList = saveActiveLabelList
 		b.hasExplicitReturn = saveHasExplicitReturn
+		if containerFlags&ContainerFlagsPropagatesThisKeyword != 0 {
+			b.seenThisKeyword = saveSeenThisKeyword || b.seenThisKeyword
+		} else {
+			b.seenThisKeyword = saveSeenThisKeyword
+		}
 	} else if containerFlags&ContainerFlagsIsInterface != 0 {
 		b.seenThisKeyword = false
 		b.bindChildren(node)
@@ -2528,13 +2539,13 @@ func GetContainerFlags(node *ast.Node) ContainerFlags {
 	case ast.KindConstructor, ast.KindClassStaticBlockDeclaration:
 		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsIsThisContainer
 	case ast.KindMethodSignature, ast.KindCallSignature, ast.KindFunctionType, ast.KindConstructSignature, ast.KindConstructorType:
-		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike
+		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsPropagatesThisKeyword
 	case ast.KindFunctionDeclaration:
 		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsIsThisContainer
 	case ast.KindFunctionExpression:
 		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsIsFunctionExpression | ContainerFlagsIsThisContainer
 	case ast.KindArrowFunction:
-		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsIsFunctionExpression
+		return ContainerFlagsIsContainer | ContainerFlagsIsControlFlowContainer | ContainerFlagsHasLocals | ContainerFlagsIsFunctionLike | ContainerFlagsIsFunctionExpression | ContainerFlagsPropagatesThisKeyword
 	case ast.KindModuleBlock:
 		return ContainerFlagsIsControlFlowContainer
 	case ast.KindPropertyDeclaration: