From dabf2a6af2f8a70a5f44dd0dd5b4f2b99a3c77d4 Mon Sep 17 00:00:00 2001
From: Nathan Shively-Sanders <293473+sandersn@users.noreply.github.com>
Date: Fri, 5 Apr 2019 16:37:27 -0700
Subject: [PATCH] Always check extends clause of classes

Even if (1) @extends is provided and (2) we're not producing
diagnostics. That's because we need to know whether the extends clause
references an imported alias.
---
 src/compiler/checker.ts                       |  9 +++++----
 .../reference/extendsTagEmit.errors.txt       | 17 ++++++++++++++++
 tests/baselines/reference/extendsTagEmit.js   | 20 +++++++++++++++++++
 .../reference/extendsTagEmit.symbols          | 14 +++++++++++++
 .../baselines/reference/extendsTagEmit.types  | 14 +++++++++++++
 .../cases/conformance/jsdoc/extendsTagEmit.ts | 12 +++++++++++
 6 files changed, 82 insertions(+), 4 deletions(-)
 create mode 100644 tests/baselines/reference/extendsTagEmit.errors.txt
 create mode 100644 tests/baselines/reference/extendsTagEmit.js
 create mode 100644 tests/baselines/reference/extendsTagEmit.symbols
 create mode 100644 tests/baselines/reference/extendsTagEmit.types
 create mode 100644 tests/cases/conformance/jsdoc/extendsTagEmit.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 3fe96ca7ac45c..3ff978c862e07 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -27424,6 +27424,11 @@ namespace ts {
                 if (languageVersion < ScriptTarget.ES2015) {
                     checkExternalEmitHelpers(baseTypeNode.parent, ExternalEmitHelpers.Extends);
                 }
+                // check both @extends and extends if both are specified.
+                const extendsNode = getClassExtendsHeritageElement(node);
+                if (extendsNode && extendsNode !== baseTypeNode) {
+                    checkExpression(extendsNode.expression);
+                }
 
                 const baseTypes = getBaseTypes(type);
                 if (baseTypes.length && produceDiagnostics) {
@@ -27432,10 +27437,6 @@ namespace ts {
                     const staticBaseType = getApparentType(baseConstructorType);
                     checkBaseTypeAccessibility(staticBaseType, baseTypeNode);
                     checkSourceElement(baseTypeNode.expression);
-                    const extendsNode = getClassExtendsHeritageElement(node);
-                    if (extendsNode && extendsNode !== baseTypeNode) {
-                        checkExpression(extendsNode.expression);
-                    }
                     if (some(baseTypeNode.typeArguments)) {
                         forEach(baseTypeNode.typeArguments, checkSourceElement);
                         for (const constructor of getConstructorsForTypeArguments(staticBaseType, baseTypeNode.typeArguments, baseTypeNode)) {
diff --git a/tests/baselines/reference/extendsTagEmit.errors.txt b/tests/baselines/reference/extendsTagEmit.errors.txt
new file mode 100644
index 0000000000000..3aef84b933e70
--- /dev/null
+++ b/tests/baselines/reference/extendsTagEmit.errors.txt
@@ -0,0 +1,17 @@
+tests/cases/conformance/jsdoc/main.js(2,15): error TS2304: Cannot find name 'Mismatch'.
+tests/cases/conformance/jsdoc/main.js(2,15): error TS8023: JSDoc '@extends Mismatch' does not match the 'extends B' clause.
+
+
+==== tests/cases/conformance/jsdoc/super.js (0 errors) ====
+    export class B { }
+    
+==== tests/cases/conformance/jsdoc/main.js (2 errors) ====
+    import { B } from './super'
+    /** @extends {Mismatch} */
+                  ~~~~~~~~
+!!! error TS2304: Cannot find name 'Mismatch'.
+                  ~~~~~~~~
+!!! error TS8023: JSDoc '@extends Mismatch' does not match the 'extends B' clause.
+    class C extends B { }
+    
+    
\ No newline at end of file
diff --git a/tests/baselines/reference/extendsTagEmit.js b/tests/baselines/reference/extendsTagEmit.js
new file mode 100644
index 0000000000000..e359eb0c83ac9
--- /dev/null
+++ b/tests/baselines/reference/extendsTagEmit.js
@@ -0,0 +1,20 @@
+//// [tests/cases/conformance/jsdoc/extendsTagEmit.ts] ////
+
+//// [super.js]
+export class B { }
+
+//// [main.js]
+import { B } from './super'
+/** @extends {Mismatch} */
+class C extends B { }
+
+
+
+//// [super.js]
+export class B {
+}
+//// [main.js]
+import { B } from './super';
+/** @extends {Mismatch} */
+class C extends B {
+}
diff --git a/tests/baselines/reference/extendsTagEmit.symbols b/tests/baselines/reference/extendsTagEmit.symbols
new file mode 100644
index 0000000000000..ff01e0059a4dd
--- /dev/null
+++ b/tests/baselines/reference/extendsTagEmit.symbols
@@ -0,0 +1,14 @@
+=== tests/cases/conformance/jsdoc/super.js ===
+export class B { }
+>B : Symbol(B, Decl(super.js, 0, 0))
+
+=== tests/cases/conformance/jsdoc/main.js ===
+import { B } from './super'
+>B : Symbol(B, Decl(main.js, 0, 8))
+
+/** @extends {Mismatch} */
+class C extends B { }
+>C : Symbol(C, Decl(main.js, 0, 27))
+>B : Symbol(B, Decl(main.js, 0, 8))
+
+
diff --git a/tests/baselines/reference/extendsTagEmit.types b/tests/baselines/reference/extendsTagEmit.types
new file mode 100644
index 0000000000000..3268796e8ac95
--- /dev/null
+++ b/tests/baselines/reference/extendsTagEmit.types
@@ -0,0 +1,14 @@
+=== tests/cases/conformance/jsdoc/super.js ===
+export class B { }
+>B : B
+
+=== tests/cases/conformance/jsdoc/main.js ===
+import { B } from './super'
+>B : typeof B
+
+/** @extends {Mismatch} */
+class C extends B { }
+>C : C
+>B : typeof B
+
+
diff --git a/tests/cases/conformance/jsdoc/extendsTagEmit.ts b/tests/cases/conformance/jsdoc/extendsTagEmit.ts
new file mode 100644
index 0000000000000..a8b3c19be5b17
--- /dev/null
+++ b/tests/cases/conformance/jsdoc/extendsTagEmit.ts
@@ -0,0 +1,12 @@
+// @allowJs: true
+// @checkJs: true
+// @target: esnext
+// @outDir: out
+// @Filename: super.js
+export class B { }
+
+// @Filename: main.js
+import { B } from './super'
+/** @extends {Mismatch} */
+class C extends B { }
+