From 38f71f31eb8cef9b442039122d5f2ae0b555283c Mon Sep 17 00:00:00 2001
From: andre-fajar-n <andrenugroho395@gmail.com>
Date: Tue, 13 Oct 2026 20:41:07 +0700
Subject: [PATCH] Fix GetTypeNodePrecedence nil panic when stripInternal strips
 type alias RHS

---
 .../transformers/declarations/transform.go        |  7 ++++++-
 .../declarationEmitStripInternalTypeAliasRHS.js   | 15 +++++++++++++++
 ...clarationEmitStripInternalTypeAliasRHS.symbols | 13 +++++++++++++
 ...declarationEmitStripInternalTypeAliasRHS.types | 10 ++++++++++
 .../declarationEmitStripInternalTypeAliasRHS.ts   |  7 +++++++
 5 files changed, 51 insertions(+), 1 deletion(-)
 create mode 100644 tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.js
 create mode 100644 tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.symbols
 create mode 100644 tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.types
 create mode 100644 tsc/testdata/tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts

diff --git a/tsc/internal/transformers/declarations/transform.go b/tsc/internal/transformers/declarations/transform.go
index f2bb66a6803cb..93d96761460fb 100644
--- a/tsc/internal/transformers/declarations/transform.go
+++ b/tsc/internal/transformers/declarations/transform.go
@@ -1791,12 +1791,17 @@ func (tx *DeclarationTransformer) transformTopLevelDeclaration(input *ast.Node)
 
 func (tx *DeclarationTransformer) transformTypeAliasDeclaration(input *ast.TypeAliasDeclaration) *ast.Node {
 	tx.needsDeclare = false
+	t := tx.Visitor().Visit(input.Type)
+	if t == nil {
+		// stripInternal can elide an @internal type RHS; fall back like index signatures
+		t = tx.Factory().NewKeywordTypeNode(ast.KindAnyKeyword)
+	}
 	return tx.Factory().UpdateTypeAliasDeclaration(
 		input,
 		tx.ensureModifiers(input.AsNode()),
 		input.Name(),
 		tx.Visitor().VisitNodes(input.TypeParameters),
-		tx.Visitor().Visit(input.Type),
+		t,
 	)
 }
 
diff --git a/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.js b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.js
new file mode 100644
index 0000000000000..42c6d66790d28
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.js
@@ -0,0 +1,15 @@
+//// [tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts] ////
+
+//// [declarationEmitStripInternalTypeAliasRHS.ts]
+interface Foo {}
+export type T =
+    /** @internal */
+    Foo;
+
+
+//// [declarationEmitStripInternalTypeAliasRHS.js]
+export {};
+
+
+//// [declarationEmitStripInternalTypeAliasRHS.d.ts]
+export type T = any;
diff --git a/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.symbols b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.symbols
new file mode 100644
index 0000000000000..0acbf814f97ab
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.symbols
@@ -0,0 +1,13 @@
+//// [tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts] ////
+
+=== declarationEmitStripInternalTypeAliasRHS.ts ===
+interface Foo {}
+>Foo : Symbol(Foo, Decl(declarationEmitStripInternalTypeAliasRHS.ts, 0, 0))
+
+export type T =
+>T : Symbol(T, Decl(declarationEmitStripInternalTypeAliasRHS.ts, 0, 16))
+
+    /** @internal */
+    Foo;
+>Foo : Symbol(Foo, Decl(declarationEmitStripInternalTypeAliasRHS.ts, 0, 0))
+
diff --git a/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.types b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.types
new file mode 100644
index 0000000000000..a048024e07e7b
--- /dev/null
+++ b/tsc/testdata/baselines/reference/compiler/declarationEmitStripInternalTypeAliasRHS.types
@@ -0,0 +1,10 @@
+//// [tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts] ////
+
+=== declarationEmitStripInternalTypeAliasRHS.ts ===
+interface Foo {}
+export type T =
+>T : Foo
+
+    /** @internal */
+    Foo;
+
diff --git a/tsc/testdata/tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts b/tsc/testdata/tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts
new file mode 100644
index 0000000000000..f64b3b8601b67
--- /dev/null
+++ b/tsc/testdata/tests/cases/compiler/declarationEmitStripInternalTypeAliasRHS.ts
@@ -0,0 +1,7 @@
+// @declaration: true
+// @stripInternal: true
+
+interface Foo {}
+export type T =
+    /** @internal */
+    Foo;