From c344a3ea5b6bacf4ecc5b5ca77c2319a2fed05de Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Tue, 10 Jul 2018 08:33:19 -0700
Subject: [PATCH] Fix bogus use before def in jsdoc (#25532)

Block scoped variables, classes and enums would issue a bogus
use-before-def error in jsdoc because name resolution always adds Value,
even when resolving a type.

Fixes #25097
---
 src/compiler/checker.ts                                |  3 ++-
 .../reference/jsdocTypeReferenceUseBeforeDef.symbols   |  9 +++++++++
 .../reference/jsdocTypeReferenceUseBeforeDef.types     | 10 ++++++++++
 .../jsdoc/jsdocTypeReferenceUseBeforeDef.ts            |  8 ++++++++
 4 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.symbols
 create mode 100644 tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.types
 create mode 100644 tests/cases/conformance/jsdoc/jsdocTypeReferenceUseBeforeDef.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3ddf460f80f..2e48c4ca1bc 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -1059,6 +1059,7 @@ namespace ts {
             // 5. inside a TS export= declaration (since we will move the export statement during emit to avoid TDZ)
             // or if usage is in a type context:
             // 1. inside a type query (typeof in type position)
+            // 2. inside a jsdoc comment
             if (usage.parent.kind === SyntaxKind.ExportSpecifier || (usage.parent.kind === SyntaxKind.ExportAssignment && (usage.parent as ExportAssignment).isExportEquals)) {
                 // export specifiers do not use the variable, they only make it available for use
                 return true;
@@ -1069,7 +1070,7 @@ namespace ts {
             }
 
             const container = getEnclosingBlockScopeContainer(declaration);
-            return isInTypeQuery(usage) || isUsedInFunctionOrInstanceProperty(usage, declaration, container);
+            return !!(usage.flags & NodeFlags.JSDoc) || isInTypeQuery(usage) || isUsedInFunctionOrInstanceProperty(usage, declaration, container);
 
             function isImmediatelyUsedInInitializerOfBlockScopedVariable(declaration: VariableDeclaration, usage: Node): boolean {
                 const container = getEnclosingBlockScopeContainer(declaration);
diff --git a/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.symbols b/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.symbols
new file mode 100644
index 00000000000..798c892f520
--- /dev/null
+++ b/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.symbols
@@ -0,0 +1,9 @@
+=== tests/cases/conformance/jsdoc/bug25097.js ===
+/** @type {C | null} */
+const c = null
+>c : Symbol(c, Decl(bug25097.js, 1, 5))
+
+class C {
+>C : Symbol(C, Decl(bug25097.js, 1, 14))
+}
+
diff --git a/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.types b/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.types
new file mode 100644
index 00000000000..0a79a140c7d
--- /dev/null
+++ b/tests/baselines/reference/jsdocTypeReferenceUseBeforeDef.types
@@ -0,0 +1,10 @@
+=== tests/cases/conformance/jsdoc/bug25097.js ===
+/** @type {C | null} */
+const c = null
+>c : C
+>null : null
+
+class C {
+>C : C
+}
+
diff --git a/tests/cases/conformance/jsdoc/jsdocTypeReferenceUseBeforeDef.ts b/tests/cases/conformance/jsdoc/jsdocTypeReferenceUseBeforeDef.ts
new file mode 100644
index 00000000000..93e735e1fa6
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/jsdocTypeReferenceUseBeforeDef.ts
@@ -0,0 +1,8 @@
+// @noEmit: true
+// @allowJs: true
+// @checkJs: true
+// @Filename: bug25097.js
+/** @type {C | null} */
+const c = null
+class C {
+}