Detect more TS syntax in JS files

* optional class methods
* type arguments on tagged template expressions

Author: ajafff

src/compiler/program.ts

@@ -1760,13 +1760,12 @@ namespace ts {
                     switch (parent.kind) {
                         case SyntaxKind.Parameter:
                         case SyntaxKind.PropertyDeclaration:
-                            if ((<ParameterDeclaration | PropertyDeclaration>parent).questionToken === node) {
+                        case SyntaxKind.MethodDeclaration:
+                            if ((<ParameterDeclaration | PropertyDeclaration | MethodDeclaration>parent).questionToken === node) {
                                 diagnostics.push(createDiagnosticForNode(node, Diagnostics._0_can_only_be_used_in_a_ts_file, "?"));
                                 return;
                             }
                         // falls through
-                        case SyntaxKind.MethodDeclaration:
-                        case SyntaxKind.MethodSignature:
                         case SyntaxKind.Constructor:
                         case SyntaxKind.GetAccessor:
                         case SyntaxKind.SetAccessor:
@@ -1835,23 +1834,22 @@ namespace ts {
                         case SyntaxKind.ClassDeclaration:
                         case SyntaxKind.ClassExpression:
                         case SyntaxKind.MethodDeclaration:
-                        case SyntaxKind.MethodSignature:
                         case SyntaxKind.Constructor:
                         case SyntaxKind.GetAccessor:
                         case SyntaxKind.SetAccessor:
                         case SyntaxKind.FunctionExpression:
                         case SyntaxKind.FunctionDeclaration:
                         case SyntaxKind.ArrowFunction:
                             // Check type parameters
-                            if (nodes === (<ClassLikeDeclaration | FunctionLikeDeclaration>parent).typeParameters) {
+                            if (nodes === (<DeclarationWithTypeParameterChildren>parent).typeParameters) {
                                 diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_parameter_declarations_can_only_be_used_in_a_ts_file));
                                 return;
                             }
                         // falls through
                         case SyntaxKind.VariableStatement:
                             // Check modifiers
-                            if (nodes === (<ClassDeclaration | FunctionLikeDeclaration | VariableStatement>parent).modifiers) {
-                                return checkModifiers(<NodeArray<Modifier>>nodes, parent.kind === SyntaxKind.VariableStatement);
+                            if (nodes === parent.modifiers) {
+                                return checkModifiers(parent.modifiers, parent.kind === SyntaxKind.VariableStatement);
                             }
                             break;
                         case SyntaxKind.PropertyDeclaration:
@@ -1877,8 +1875,9 @@ namespace ts {
                         case SyntaxKind.ExpressionWithTypeArguments:
                         case SyntaxKind.JsxSelfClosingElement:
                         case SyntaxKind.JsxOpeningElement:
+                        case SyntaxKind.TaggedTemplateExpression:
                             // Check type arguments
-                            if (nodes === (<CallExpression | NewExpression | ExpressionWithTypeArguments | JsxOpeningLikeElement>parent).typeArguments) {
+                            if (nodes === (<NodeWithTypeArguments>parent).typeArguments) {
                                 diagnostics.push(createDiagnosticForNodeArray(nodes, Diagnostics.type_arguments_can_only_be_used_in_a_ts_file));
                                 return;
                             }

tests/baselines/reference/jsFileCompilationOptionalClassElementSyntaxOfClass.errors.txt

@@ -0,0 +1,18 @@
+error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+tests/cases/compiler/a.js(2,8): error TS8009: '?' can only be used in a .ts file.
+tests/cases/compiler/a.js(4,8): error TS8009: '?' can only be used in a .ts file.
+
+
+!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
+!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
+==== tests/cases/compiler/a.js (2 errors) ====
+    class C {
+        foo?() {
+           ~
+!!! error TS8009: '?' can only be used in a .ts file.
+        }
+        bar? = 1; 
+           ~
+!!! error TS8009: '?' can only be used in a .ts file.
+    }

tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.errors.txt

@@ -1,11 +1,19 @@
-error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
-  Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-tests/cases/compiler/a.js(1,5): error TS8011: 'type arguments' can only be used in a .ts file.
+tests/cases/compiler/a.jsx(1,5): error TS8011: 'type arguments' can only be used in a .ts file.
+tests/cases/compiler/a.jsx(2,5): error TS8011: 'type arguments' can only be used in a .ts file.
+tests/cases/compiler/a.jsx(3,6): error TS8011: 'type arguments' can only be used in a .ts file.
+tests/cases/compiler/a.jsx(4,6): error TS8011: 'type arguments' can only be used in a .ts file.
 
 
-!!! error TS5055: Cannot write file 'tests/cases/compiler/a.js' because it would overwrite input file.
-!!! error TS5055:   Adding a tsconfig.json file will help organize projects that contain both TypeScript and JavaScript files. Learn more at https://aka.ms/tsconfig.
-==== tests/cases/compiler/a.js (1 errors) ====
+==== tests/cases/compiler/a.jsx (4 errors) ====
     Foo<number>();
         ~~~~~~
+!!! error TS8011: 'type arguments' can only be used in a .ts file.
+    Foo<number>``;
+        ~~~~~~
+!!! error TS8011: 'type arguments' can only be used in a .ts file.
+    <Foo<number>></Foo>;
+         ~~~~~~
+!!! error TS8011: 'type arguments' can only be used in a .ts file.
+    <Foo<number>/>;
+         ~~~~~~
 !!! error TS8011: 'type arguments' can only be used in a .ts file.

tests/baselines/reference/jsFileCompilationTypeArgumentSyntaxOfCall.js

@@ -0,0 +1,15 @@
+//// [a.jsx]
+Foo<number>();
+Foo<number>``;
+<Foo<number>></Foo>;
+<Foo<number>/>;
+
+//// [a.js]
+var __makeTemplateObject = (this && this.__makeTemplateObject) || function (cooked, raw) {
+    if (Object.defineProperty) { Object.defineProperty(cooked, "raw", { value: raw }); } else { cooked.raw = raw; }
+    return cooked;
+};
+Foo();
+Foo(__makeTemplateObject([""], [""]));
+<Foo></Foo>;
+<Foo />;

tests/cases/compiler/jsFileCompilationOptionalClassElementSyntaxOfClass.ts

@@ -0,0 +1,8 @@
+// @allowJs: true
+// @noTypesAndSymbols: true
+// @filename: a.js
+class C {
+    foo?() {
+    }
+    bar? = 1; 
+}

tests/cases/compiler/jsFileCompilationTypeArgumentSyntaxOfCall.ts

@@ -1,3 +1,7 @@
 // @allowJs: true
-// @filename: a.js
-Foo<number>();
+// @noTypesAndSymbols: true
+// @filename: a.jsx
+Foo<number>();
+Foo<number>``;
+<Foo<number>></Foo>;
+<Foo<number>/>;