From ca324a0af5cea00b44ab63d396d8565c258772f0 Mon Sep 17 00:00:00 2001
From: magierjones <simon.jaeger@magierjones.de>
Date: Mon, 9 Sep 2019 10:14:57 +0200
Subject: [PATCH] fix #32843 : evaluate right scope when checked if all type
 parameter are unused for jsdoc `@template`

---
 src/compiler/checker.ts                       |  2 +-
 ...usedTypeParameters_templateTag2.errors.txt | 42 +++++++++++++++++++
 .../unusedTypeParameters_templateTag2.symbols | 40 ++++++++++++++++++
 .../unusedTypeParameters_templateTag2.types   | 40 ++++++++++++++++++
 .../unusedTypeParameters_templateTag2.ts      | 34 +++++++++++++++
 5 files changed, 157 insertions(+), 1 deletion(-)
 create mode 100644 tests/baselines/reference/unusedTypeParameters_templateTag2.errors.txt
 create mode 100644 tests/baselines/reference/unusedTypeParameters_templateTag2.symbols
 create mode 100644 tests/baselines/reference/unusedTypeParameters_templateTag2.types
 create mode 100644 tests/cases/compiler/unusedTypeParameters_templateTag2.ts

diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 758b6252ea957..69b5d62a0e627 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -27386,7 +27386,7 @@ namespace ts {
                             ? rangeOfNode(parent)
                             // Include the `<>` in the error message
                             : rangeOfTypeParameters(parent.typeParameters!);
-                        const only = typeParameters.length === 1;
+                        const only = parent.typeParameters!.length === 1;
                         const message = only ? Diagnostics._0_is_declared_but_its_value_is_never_read : Diagnostics.All_type_parameters_are_unused;
                         const arg0 = only ? name : undefined;
                         addDiagnostic(typeParameter, UnusedKind.Parameter, createFileDiagnostic(getSourceFileOfNode(parent), range.pos, range.end - range.pos, message, arg0));
diff --git a/tests/baselines/reference/unusedTypeParameters_templateTag2.errors.txt b/tests/baselines/reference/unusedTypeParameters_templateTag2.errors.txt
new file mode 100644
index 0000000000000..40da52ffbd7ea
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters_templateTag2.errors.txt
@@ -0,0 +1,42 @@
+/a.js(3,4): error TS6133: 'V' is declared but its value is never read.
+/a.js(13,4): error TS6205: All type parameters are unused
+/a.js(20,16): error TS6133: 'V' is declared but its value is never read.
+/a.js(20,18): error TS6133: 'X' is declared but its value is never read.
+
+
+==== /a.js (4 errors) ====
+    /**
+     * @template T
+     * @template V
+       ~~~~~~~~~~~
+!!! error TS6133: 'V' is declared but its value is never read.
+     */
+    class C1 {
+        constructor() {
+            /** @type {T} */
+            this.p;
+        }
+    }
+    
+    /**
+     * @template T,V
+       ~~~~~~~~~~~~~
+!!! error TS6205: All type parameters are unused
+     */
+    class C2 {
+        constructor() { }
+    }
+    
+    /**
+     * @template T,V,X
+                   ~
+!!! error TS6133: 'V' is declared but its value is never read.
+                     ~
+!!! error TS6133: 'X' is declared but its value is never read.
+     */
+    class C3 {
+        constructor() {
+            /** @type {T} */
+            this.p;
+        }
+    }
\ No newline at end of file
diff --git a/tests/baselines/reference/unusedTypeParameters_templateTag2.symbols b/tests/baselines/reference/unusedTypeParameters_templateTag2.symbols
new file mode 100644
index 0000000000000..c38b52a9bbdfa
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters_templateTag2.symbols
@@ -0,0 +1,40 @@
+=== /a.js ===
+/**
+ * @template T
+ * @template V
+ */
+class C1 {
+>C1 : Symbol(C1, Decl(a.js, 0, 0))
+
+    constructor() {
+        /** @type {T} */
+        this.p;
+>this.p : Symbol(C1.p, Decl(a.js, 5, 19))
+>this : Symbol(C1, Decl(a.js, 0, 0))
+>p : Symbol(C1.p, Decl(a.js, 5, 19))
+    }
+}
+
+/**
+ * @template T,V
+ */
+class C2 {
+>C2 : Symbol(C2, Decl(a.js, 9, 1))
+
+    constructor() { }
+}
+
+/**
+ * @template T,V,X
+ */
+class C3 {
+>C3 : Symbol(C3, Decl(a.js, 16, 1))
+
+    constructor() {
+        /** @type {T} */
+        this.p;
+>this.p : Symbol(C3.p, Decl(a.js, 22, 19))
+>this : Symbol(C3, Decl(a.js, 16, 1))
+>p : Symbol(C3.p, Decl(a.js, 22, 19))
+    }
+}
diff --git a/tests/baselines/reference/unusedTypeParameters_templateTag2.types b/tests/baselines/reference/unusedTypeParameters_templateTag2.types
new file mode 100644
index 0000000000000..45e33a5e3799e
--- /dev/null
+++ b/tests/baselines/reference/unusedTypeParameters_templateTag2.types
@@ -0,0 +1,40 @@
+=== /a.js ===
+/**
+ * @template T
+ * @template V
+ */
+class C1 {
+>C1 : C1<T, V>
+
+    constructor() {
+        /** @type {T} */
+        this.p;
+>this.p : T
+>this : this
+>p : T
+    }
+}
+
+/**
+ * @template T,V
+ */
+class C2 {
+>C2 : C2<T, V>
+
+    constructor() { }
+}
+
+/**
+ * @template T,V,X
+ */
+class C3 {
+>C3 : C3<T, V, X>
+
+    constructor() {
+        /** @type {T} */
+        this.p;
+>this.p : T
+>this : this
+>p : T
+    }
+}
diff --git a/tests/cases/compiler/unusedTypeParameters_templateTag2.ts b/tests/cases/compiler/unusedTypeParameters_templateTag2.ts
new file mode 100644
index 0000000000000..5db7a82a89804
--- /dev/null
+++ b/tests/cases/compiler/unusedTypeParameters_templateTag2.ts
@@ -0,0 +1,34 @@
+// @allowJs: true
+// @checkJs: true
+// @noEmit: true
+// @noUnusedParameters:true
+
+// @Filename: /a.js
+
+/**
+ * @template T
+ * @template V
+ */
+class C1 {
+    constructor() {
+        /** @type {T} */
+        this.p;
+    }
+}
+
+/**
+ * @template T,V
+ */
+class C2 {
+    constructor() { }
+}
+
+/**
+ * @template T,V,X
+ */
+class C3 {
+    constructor() {
+        /** @type {T} */
+        this.p;
+    }
+}
\ No newline at end of file