From 5bbedac7fc2cab8c4b8c966b323f44eda73885b6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mateusz=20Burzy=C5=84ski?= <mateuszburzynski@gmail.com>
Date: Sun, 23 Aug 2026 09:56:47 +0200
Subject: [PATCH] Fix crash on malformed object destructuring assignment

---
 .../transformers/estransforms/classfields.go  |  1 -
 ...tructuringAssignmentClassFields.errors.txt | 20 +++++++++++++++++++
 ...bjectDestructuringAssignmentClassFields.js | 10 ++++++++++
 ...DestructuringAssignmentClassFields.symbols |  8 ++++++++
 ...ctDestructuringAssignmentClassFields.types | 15 ++++++++++++++
 ...bjectDestructuringAssignmentClassFields.ts |  1 +
 6 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100644 tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.errors.txt
 create mode 100644 tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.js
 create mode 100644 tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.symbols
 create mode 100644 tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.types
 create mode 100644 tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts

diff --git a/tsc/internal/transformers/estransforms/classfields.go b/tsc/internal/transformers/estransforms/classfields.go
index 68dc3950413d9..02742c9571cb5 100644
--- a/tsc/internal/transformers/estransforms/classfields.go
+++ b/tsc/internal/transformers/estransforms/classfields.go
@@ -3318,7 +3318,6 @@ func (tx *classFieldsTransformer) visitAssignmentRestProperty(node *ast.Node) *a
 }
 
 func (tx *classFieldsTransformer) visitObjectAssignmentElement(node *ast.Node) *ast.Node {
-	debug.Assert(node != nil && ast.IsObjectBindingOrAssignmentElement(node))
 	if ast.IsSpreadAssignment(node) {
 		return tx.visitAssignmentRestProperty(node)
 	}
diff --git a/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.errors.txt b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.errors.txt
new file mode 100644
index 0000000000000..87e4aba639e60
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.errors.txt
@@ -0,0 +1,20 @@
+malformedObjectDestructuringAssignmentClassFields.ts(1,3): error TS1136: Property assignment expected.
+malformedObjectDestructuringAssignmentClassFields.ts(1,6): error TS1005: ',' expected.
+malformedObjectDestructuringAssignmentClassFields.ts(1,7): error TS1127: Invalid character.
+malformedObjectDestructuringAssignmentClassFields.ts(1,10): error TS1109: Expression expected.
+malformedObjectDestructuringAssignmentClassFields.ts(2,1): error TS1005: ')' expected.
+
+
+==== malformedObjectDestructuringAssignmentClassFields.ts (5 errors) ====
+    ({x(A.#}=
+      ~
+!!! error TS1136: Property assignment expected.
+         ~
+!!! error TS1005: ',' expected.
+          ~
+!!! error TS1127: Invalid character.
+             
+!!! error TS1109: Expression expected.
+    
+    
+!!! error TS1005: ')' expected.
\ No newline at end of file
diff --git a/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.js b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.js
new file mode 100644
index 0000000000000..1416d26fea47e
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.js
@@ -0,0 +1,10 @@
+//// [tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts] ////
+
+//// [malformedObjectDestructuringAssignmentClassFields.ts]
+({x(A.#}=
+
+
+//// [malformedObjectDestructuringAssignmentClassFields.js]
+"use strict";
+({ x(A) { }, : .# } =
+);
diff --git a/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.symbols b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.symbols
new file mode 100644
index 0000000000000..ec5eb7d8d85c9
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.symbols
@@ -0,0 +1,8 @@
+//// [tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts] ////
+
+=== malformedObjectDestructuringAssignmentClassFields.ts ===
+({x(A.#}=
+>x : Symbol(x, Decl(malformedObjectDestructuringAssignmentClassFields.ts, 0, 2))
+>A : Symbol(A, Decl(malformedObjectDestructuringAssignmentClassFields.ts, 0, 4))
+> : Symbol((Missing), Decl(malformedObjectDestructuringAssignmentClassFields.ts, 0, 5))
+
diff --git a/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.types b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.types
new file mode 100644
index 0000000000000..46e410d3b1385
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/malformedObjectDestructuringAssignmentClassFields.types
@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts] ////
+
+=== malformedObjectDestructuringAssignmentClassFields.ts ===
+({x(A.#}=
+>({x(A.#}= : any
+>{x(A.#}= : any
+>{x(A.#} : { x(A: any): any; "": any; }
+>x : (A: any) => any
+>A : any
+> : any
+>.# : any
+> : any
+
+> : any
+
diff --git a/tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts b/tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts
new file mode 100644
index 0000000000000..fef8375cad5cd
--- /dev/null
+++ b/tsc/testdata/tests/cases/compiler/malformedObjectDestructuringAssignmentClassFields.ts
@@ -0,0 +1 @@
+({x(A.#}=