From 2d501b1d98e0424991e95cf0038afd97520b65bc Mon Sep 17 00:00:00 2001
From: Oleksandr T <oleksandr.tarasiuk@outlook.com>
Date: Fri, 28 Jan 2022 22:19:48 +0200
Subject: [PATCH] fix(47582): skip extraction if the type node is in the range
 of the type parameter declaration (#47596)

---
 src/services/refactors/extractType.ts         | 19 ++++++++++++++-----
 .../cases/fourslash/refactorExtractType72.ts  |  6 ++++++
 .../cases/fourslash/refactorExtractType73.ts  | 11 +++++++++++
 .../cases/fourslash/refactorExtractType74.ts  | 15 +++++++++++++++
 .../cases/fourslash/refactorExtractType75.ts  |  9 +++++++++
 5 files changed, 55 insertions(+), 5 deletions(-)
 create mode 100644 tests/cases/fourslash/refactorExtractType72.ts
 create mode 100644 tests/cases/fourslash/refactorExtractType73.ts
 create mode 100644 tests/cases/fourslash/refactorExtractType74.ts
 create mode 100644 tests/cases/fourslash/refactorExtractType75.ts

diff --git a/src/services/refactors/extractType.ts b/src/services/refactors/extractType.ts
index e932c9fcc15..0e16def63fe 100644
--- a/src/services/refactors/extractType.ts
+++ b/src/services/refactors/extractType.ts
@@ -144,11 +144,20 @@ namespace ts.refactor {
         function visitor(node: Node): true | undefined {
             if (isTypeReferenceNode(node)) {
                 if (isIdentifier(node.typeName)) {
-                    const symbol = checker.resolveName(node.typeName.text, node.typeName, SymbolFlags.TypeParameter, /* excludeGlobals */ true);
-                    const declaration = tryCast(symbol?.declarations?.[0], isTypeParameterDeclaration);
-                    if (declaration) {
-                        if (rangeContainsSkipTrivia(statement, declaration, file) && !rangeContainsSkipTrivia(selection, declaration, file)) {
-                            pushIfUnique(result, declaration);
+                    const typeName = node.typeName;
+                    const symbol = checker.resolveName(typeName.text, typeName, SymbolFlags.TypeParameter, /* excludeGlobals */ true);
+                    for (const decl of symbol?.declarations || emptyArray) {
+                        if (isTypeParameterDeclaration(decl) && decl.getSourceFile() === file) {
+                            // skip extraction if the type node is in the range of the type parameter declaration.
+                            // function foo<T extends { a?: /**/T }>(): void;
+                            if (decl.name.escapedText === typeName.escapedText && rangeContainsSkipTrivia(decl, selection, file)) {
+                                return true;
+                            }
+
+                            if (rangeContainsSkipTrivia(statement, decl, file) && !rangeContainsSkipTrivia(selection, decl, file)) {
+                                pushIfUnique(result, decl);
+                                break;
+                            }
                         }
                     }
                 }
diff --git a/tests/cases/fourslash/refactorExtractType72.ts b/tests/cases/fourslash/refactorExtractType72.ts
new file mode 100644
index 00000000000..d56f71938e8
--- /dev/null
+++ b/tests/cases/fourslash/refactorExtractType72.ts
@@ -0,0 +1,6 @@
+/// <reference path='fourslash.ts' />
+
+////export declare function foo<T extends { a?: /*a*/T/*b*/ }>(): void;
+
+goTo.select("a", "b");
+verify.not.refactorAvailable("Extract type", "Extract to type alias");
diff --git a/tests/cases/fourslash/refactorExtractType73.ts b/tests/cases/fourslash/refactorExtractType73.ts
new file mode 100644
index 00000000000..8eab5d632a7
--- /dev/null
+++ b/tests/cases/fourslash/refactorExtractType73.ts
@@ -0,0 +1,11 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: a.ts
+////interface Foo<T extends { prop: T }> {}
+
+// @Filename: b.ts
+////interface Foo<T extends { prop: /*a*/T/*b*/ }> {}
+
+goTo.file("b.ts");
+goTo.select("a", "b");
+verify.not.refactorAvailable("Extract type", "Extract to type alias");
diff --git a/tests/cases/fourslash/refactorExtractType74.ts b/tests/cases/fourslash/refactorExtractType74.ts
new file mode 100644
index 00000000000..5434c8c9b27
--- /dev/null
+++ b/tests/cases/fourslash/refactorExtractType74.ts
@@ -0,0 +1,15 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: a.ts
+//// interface Foo<T extends { prop: [|T|] }> {}
+
+// @Filename: b.ts
+//// // Some initial comments.
+//// // We need to ensure these files have different contents,
+//// // so their ranges differ, so we'll start a few lines below in this file.
+//// interface Foo<T extends { prop: [|T|] }> {}
+
+for (const range of test.ranges()) {
+    goTo.selectRange(range);
+    verify.not.refactorAvailable("Extract type", "Extract to type alias");
+}
diff --git a/tests/cases/fourslash/refactorExtractType75.ts b/tests/cases/fourslash/refactorExtractType75.ts
new file mode 100644
index 00000000000..f213cdd80da
--- /dev/null
+++ b/tests/cases/fourslash/refactorExtractType75.ts
@@ -0,0 +1,9 @@
+/// <reference path='fourslash.ts' />
+
+// @Filename: a.ts
+//// interface Foo<T extends { prop: T }> {}
+//// interface Foo<T extends { prop: /*a*/T/*b*/ }> {}
+
+goTo.file("a.ts");
+goTo.select("a", "b");
+verify.not.refactorAvailable("Extract type", "Extract to type alias");