diff --git a/internal/ast/utilities.go b/internal/ast/utilities.go
index 5c5fd2314d..8c6f65c04b 100644
--- a/internal/ast/utilities.go
+++ b/internal/ast/utilities.go
@@ -1507,7 +1507,7 @@ func GetAssignmentDeclarationKind(bin *BinaryExpression) JSDeclarationKind {
 	if IsInJSFile(bin.Left) && bin.Left.Expression().Kind == KindThisKeyword {
 		return JSDeclarationKindThisProperty
 	}
-	if bin.Left.Kind == KindPropertyAccessExpression && IsEntityNameExpressionEx(bin.Left.Expression(), IsInJSFile(bin.Left)) && IsIdentifier(bin.Left.Name()) ||
+	if bin.Left.Kind == KindPropertyAccessExpression && IsEntityNameExpressionEx(bin.Left.Expression(), IsInJSFile(bin.Left)) && bin.Left.Name() != nil && IsIdentifier(bin.Left.Name()) ||
 		bin.Left.Kind == KindElementAccessExpression && IsEntityNameExpressionEx(bin.Left.Expression(), IsInJSFile(bin.Left)) {
 		return JSDeclarationKindProperty
 	}
diff --git a/testdata/baselines/reference/compiler/crash-on-neo-async.js b/testdata/baselines/reference/compiler/crash-on-neo-async.js
new file mode 100644
index 0000000000..55bd99f57f
--- /dev/null
+++ b/testdata/baselines/reference/compiler/crash-on-neo-async.js
@@ -0,0 +1,46 @@
+//// [tests/cases/compiler/crash-on-neo-async.ts] ////
+
+//// [crash-on-neo-async.js]
+// This test reproduces a crash that occurs when parsing files like webpack/node_modules/neo-async/async.js
+// The crash happens in GetAssignmentDeclarationKind when checking IsIdentifier(bin.Left.Name())
+// where bin.Left.Name() returns nil for ElementAccessExpression
+// Pattern that causes the crash - element access assignment
+var obj = {};
+var prop = 'test';
+// This assignment with element access should not crash
+// It previously crashed because ElementAccessExpression.Name() returns nil
+// and IsIdentifier was called on that nil value
+obj[prop] = function () {
+    return 42;
+};
+// Property access assignment should work fine (has a valid Name())
+obj.prop2 = function () {
+    return 43;
+};
+// Nested element access assignment
+obj['nested'][prop] = function () {
+    return 44;
+};
+
+
+//// [crash-on-neo-async.js]
+// This test reproduces a crash that occurs when parsing files like webpack/node_modules/neo-async/async.js
+// The crash happens in GetAssignmentDeclarationKind when checking IsIdentifier(bin.Left.Name())
+// where bin.Left.Name() returns nil for ElementAccessExpression
+// Pattern that causes the crash - element access assignment
+var obj = {};
+var prop = 'test';
+// This assignment with element access should not crash
+// It previously crashed because ElementAccessExpression.Name() returns nil
+// and IsIdentifier was called on that nil value
+obj[prop] = function () {
+    return 42;
+};
+// Property access assignment should work fine (has a valid Name())
+obj.prop2 = function () {
+    return 43;
+};
+// Nested element access assignment
+obj['nested'][prop] = function () {
+    return 44;
+};
diff --git a/testdata/baselines/reference/compiler/crash-on-neo-async.symbols b/testdata/baselines/reference/compiler/crash-on-neo-async.symbols
new file mode 100644
index 0000000000..de159102ef
--- /dev/null
+++ b/testdata/baselines/reference/compiler/crash-on-neo-async.symbols
@@ -0,0 +1,38 @@
+//// [tests/cases/compiler/crash-on-neo-async.ts] ////
+
+=== crash-on-neo-async.js ===
+// This test reproduces a crash that occurs when parsing files like webpack/node_modules/neo-async/async.js
+// The crash happens in GetAssignmentDeclarationKind when checking IsIdentifier(bin.Left.Name())
+// where bin.Left.Name() returns nil for ElementAccessExpression
+// Pattern that causes the crash - element access assignment
+var obj = {};
+>obj : Symbol(obj, Decl(crash-on-neo-async.js, 4, 3))
+
+var prop = 'test';
+>prop : Symbol(prop, Decl(crash-on-neo-async.js, 5, 3))
+
+// This assignment with element access should not crash
+// It previously crashed because ElementAccessExpression.Name() returns nil
+// and IsIdentifier was called on that nil value
+obj[prop] = function () {
+>obj : Symbol(obj, Decl(crash-on-neo-async.js, 4, 3))
+>prop : Symbol(prop, Decl(crash-on-neo-async.js, 5, 3))
+
+    return 42;
+};
+// Property access assignment should work fine (has a valid Name())
+obj.prop2 = function () {
+>obj.prop2 : Symbol(prop2, Decl(crash-on-neo-async.js, 11, 2))
+>obj : Symbol(obj, Decl(crash-on-neo-async.js, 4, 3))
+>prop2 : Symbol(prop2, Decl(crash-on-neo-async.js, 11, 2))
+
+    return 43;
+};
+// Nested element access assignment
+obj['nested'][prop] = function () {
+>obj : Symbol(obj, Decl(crash-on-neo-async.js, 4, 3))
+>prop : Symbol(prop, Decl(crash-on-neo-async.js, 5, 3))
+
+    return 44;
+};
+
diff --git a/testdata/baselines/reference/compiler/crash-on-neo-async.types b/testdata/baselines/reference/compiler/crash-on-neo-async.types
new file mode 100644
index 0000000000..6def691b25
--- /dev/null
+++ b/testdata/baselines/reference/compiler/crash-on-neo-async.types
@@ -0,0 +1,56 @@
+//// [tests/cases/compiler/crash-on-neo-async.ts] ////
+
+=== crash-on-neo-async.js ===
+// This test reproduces a crash that occurs when parsing files like webpack/node_modules/neo-async/async.js
+// The crash happens in GetAssignmentDeclarationKind when checking IsIdentifier(bin.Left.Name())
+// where bin.Left.Name() returns nil for ElementAccessExpression
+// Pattern that causes the crash - element access assignment
+var obj = {};
+>obj : { prop2: () => number; }
+>{} : { prop2: () => number; }
+
+var prop = 'test';
+>prop : string
+>'test' : "test"
+
+// This assignment with element access should not crash
+// It previously crashed because ElementAccessExpression.Name() returns nil
+// and IsIdentifier was called on that nil value
+obj[prop] = function () {
+>obj[prop] = function () {    return 42;} : () => number
+>obj[prop] : any
+>obj : { prop2: () => number; }
+>prop : string
+>function () {    return 42;} : () => number
+
+    return 42;
+>42 : 42
+
+};
+// Property access assignment should work fine (has a valid Name())
+obj.prop2 = function () {
+>obj.prop2 = function () {    return 43;} : () => number
+>obj.prop2 : () => number
+>obj : { prop2: () => number; }
+>prop2 : () => number
+>function () {    return 43;} : () => number
+
+    return 43;
+>43 : 43
+
+};
+// Nested element access assignment
+obj['nested'][prop] = function () {
+>obj['nested'][prop] = function () {    return 44;} : () => number
+>obj['nested'][prop] : any
+>obj['nested'] : any
+>obj : { prop2: () => number; }
+>'nested' : "nested"
+>prop : string
+>function () {    return 44;} : () => number
+
+    return 44;
+>44 : 44
+
+};
+
diff --git a/testdata/tests/cases/compiler/crash-on-neo-async.ts b/testdata/tests/cases/compiler/crash-on-neo-async.ts
new file mode 100644
index 0000000000..9e30af1aa9
--- /dev/null
+++ b/testdata/tests/cases/compiler/crash-on-neo-async.ts
@@ -0,0 +1,22 @@
+// @checkJs: true
+// @filename: crash-on-neo-async.js
+// This test reproduces a crash that occurs when parsing files like webpack/node_modules/neo-async/async.js
+// The crash happens in GetAssignmentDeclarationKind when checking IsIdentifier(bin.Left.Name())
+// where bin.Left.Name() returns nil for ElementAccessExpression
+// Pattern that causes the crash - element access assignment
+var obj = {};
+var prop = 'test';
+// This assignment with element access should not crash
+// It previously crashed because ElementAccessExpression.Name() returns nil
+// and IsIdentifier was called on that nil value
+obj[prop] = function () {
+    return 42;
+};
+// Property access assignment should work fine (has a valid Name())
+obj.prop2 = function () {
+    return 43;
+};
+// Nested element access assignment
+obj['nested'][prop] = function () {
+    return 44;
+};