Allow expectError assertions to detect this type mismatches on class methods (#105)

Author: BendingBender

source/lib/compiler.ts

@@ -26,7 +26,8 @@ const expectErrordiagnosticCodesToIgnore = new Set<DiagnosticCode>([
 	DiagnosticCode.ExpectedArgumentsButGotOther,
 	DiagnosticCode.NoOverloadMatches,
 	DiagnosticCode.PropertyMissingInType1ButRequiredInType2,
-	DiagnosticCode.TypeHasNoPropertiesInCommonWith
+	DiagnosticCode.TypeHasNoPropertiesInCommonWith,
+	DiagnosticCode.ThisContextOfTypeNotAssignableToMethodOfThisType
 ]);
 
 /**

source/lib/interfaces.ts

@@ -32,6 +32,7 @@ export enum DiagnosticCode {
 	TypeHasNoPropertiesInCommonWith = 2559,
 	NoOverloadMatches = 2769,
 	PropertyMissingInType1ButRequiredInType2 = 2741,
+	ThisContextOfTypeNotAssignableToMethodOfThisType = 2684,
 }
 
 export interface Diagnostic {

source/test/fixtures/expect-error/classes/index.d.ts

@@ -0,0 +1,4 @@
+export declare class Foo<T> {
+	public bar(this: Foo<void>): void;
+	public bar(value: T): void;
+}

source/test/fixtures/expect-error/classes/index.js

@@ -0,0 +1,9 @@
+class Foo {
+	bar(value) {
+		if (value) {
+			this.val = value;
+		}
+	}
+}
+
+module.exports.Foo = Foo;

source/test/fixtures/expect-error/classes/index.test-d.ts

@@ -0,0 +1,6 @@
+import {expectError} from '../../../..';
+import {Foo} from '.';
+
+const numberFoo = new Foo<number>();
+
+expectError(numberFoo.bar());

source/test/fixtures/expect-error/classes/package.json

@@ -0,0 +1,3 @@
+{
+	"name": "foo"
+}

source/test/test.ts

@@ -183,6 +183,12 @@ test('support setting a custom test directory', async t => {
 	]);
 });
 
+test('expectError for classes', async t => {
+	const diagnostics = await tsd({cwd: path.join(__dirname, 'fixtures/expect-error/classes')});
+
+	verify(t, diagnostics, []);
+});
+
 test('expectError for functions', async t => {
 	const diagnostics = await tsd({cwd: path.join(__dirname, 'fixtures/expect-error/functions')});