feat(911): erasableSyntaxOnly not supported

internal/checker/checker.go

@@ -2470,6 +2470,9 @@ func (c *Checker) checkParameter(node *ast.Node) {
 		paramName = node.Name().Text()
 	}
 	if ast.HasSyntacticModifier(node, ast.ModifierFlagsParameterPropertyModifier) {
+		if c.compilerOptions.ErasableSyntaxOnly.IsTrue() {
+			c.error(node, diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled)
+		}
 		if !(ast.IsConstructorDeclaration(fn) && ast.NodeIsPresent(fn.Body())) {
 			c.error(node, diagnostics.A_parameter_property_is_only_allowed_in_a_constructor_implementation)
 		}
@@ -4785,6 +4788,11 @@ func (c *Checker) checkEnumDeclaration(node *ast.Node) {
 	c.checkCollisionsForDeclarationName(node, node.Name())
 	c.checkExportsOnMergedDeclarations(node)
 	c.checkSourceElements(node.Members())
+
+	if c.compilerOptions.ErasableSyntaxOnly.IsTrue() && node.Flags&ast.NodeFlagsAmbient == 0 {
+		c.error(node, diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled)
+	}
+
 	c.computeEnumMemberValues(node)
 	// Spec 2014 - Section 9.3:
 	// It isn't possible for one enum declaration to continue the automatic numbering sequence of another,
@@ -4871,6 +4879,9 @@ func (c *Checker) checkModuleDeclaration(node *ast.Node) {
 	symbol := c.getSymbolOfDeclaration(node)
 	// The following checks only apply on a non-ambient instantiated module declaration.
 	if symbol.Flags&ast.SymbolFlagsValueModule != 0 && !inAmbientContext && isInstantiatedModule(node, c.compilerOptions.ShouldPreserveConstEnums()) {
+		if c.compilerOptions.ErasableSyntaxOnly.IsTrue() {
+			c.error(node, diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled)
+		}
 		if c.compilerOptions.GetIsolatedModules() && ast.GetSourceFileOfNode(node).ExternalModuleIndicator == nil {
 			// This could be loosened a little if needed. The only problem we are trying to avoid is unqualified
 			// references to namespace members declared in other files. But use of namespaces is discouraged anyway,
@@ -5161,6 +5172,9 @@ func (c *Checker) checkImportEqualsDeclaration(node *ast.Node) {
 		return // If we hit an import declaration in an illegal context, just bail out to avoid cascading errors.
 	}
 	c.checkGrammarModifiers(node)
+	if c.compilerOptions.ErasableSyntaxOnly.IsTrue() && node.Flags&ast.NodeFlagsAmbient == 0 {
+		c.error(node, diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled)
+	}
 	if ast.IsInternalModuleImportEqualsDeclaration(node) || c.checkExternalImportOrExportDeclaration(node) {
 		c.checkImportBinding(node)
 		c.markLinkedReferences(node, ReferenceHintExportImportEquals, nil, nil)
@@ -5260,6 +5274,9 @@ func (c *Checker) checkExportAssignment(node *ast.Node) {
 	if c.checkGrammarModuleElementContext(node, illegalContextMessage) {
 		return // If we hit an export assignment in an illegal context, just bail out to avoid cascading errors.
 	}
+	if c.compilerOptions.ErasableSyntaxOnly.IsTrue() && node.AsExportAssignment().IsExportEquals && node.Flags&ast.NodeFlagsAmbient == 0 {
+		c.error(node, diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled)
+	}
 	container := node.Parent
 	if !ast.IsSourceFile(container) {
 		container = container.Parent
@@ -11653,6 +11670,11 @@ func (c *Checker) classDeclarationExtendsNull(classDecl *ast.Node) bool {
 }
 
 func (c *Checker) checkAssertion(node *ast.Node, checkMode CheckMode) *Type {
+	if node.Kind == ast.KindTypeAssertionExpression {
+		if c.compilerOptions.ErasableSyntaxOnly.IsTrue() {
+			c.diagnostics.Add(ast.NewDiagnostic(ast.GetSourceFileOfNode(node), core.NewTextRange(scanner.SkipTrivia(ast.GetSourceFileOfNode(node).Text(), node.Pos()), node.Expression().Pos()), diagnostics.This_syntax_is_not_allowed_when_erasableSyntaxOnly_is_enabled))
+		}
+	}
 	typeNode := node.Type()
 	exprType := c.checkExpressionEx(node.Expression(), checkMode)
 	if isConstTypeReference(typeNode) {

testdata/baselines/reference/submodule/compiler/erasableSyntaxOnly.errors.txt

@@ -1,36 +1,74 @@
 error TS2318: Cannot find global type 'IterableIterator'.
+commonjs.cts(1,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+commonjs.cts(2,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(3,17): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(6,11): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(10,11): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(16,11): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(17,15): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(22,6): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(26,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(28,12): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(67,6): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(68,6): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(69,7): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(72,6): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(73,7): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(74,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(79,11): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(81,12): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(86,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(89,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(90,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
+index.ts(94,1): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
 
 !!! error TS2318: Cannot find global type 'IterableIterator'.
-==== index.ts (0 errors) ====
+==== index.ts (20 errors) ====
     class MyClassErr {
         // No parameter properties
         constructor(public foo: string) { }
+                    ~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     }
 
     namespace IllegalBecauseInstantiated {
+              ~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
         export const m = 1;
     }
 
     namespace AlsoIllegalBecauseInstantiated {
+              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
         class PrivateClass {
 
         }
     }
 
     namespace IllegalBecauseNestedInstantiated {
+              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
         namespace Nested {
+                  ~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
             export const m = 1;
         }
     }
 
     enum NotLegalEnum {
+         ~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
         B = 1
     }
 
     import NoGoodAlias = NotLegalEnum.B;
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
     const enum NotLegalConstEnum {
+               ~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
         C = 2
     }
 
@@ -70,37 +108,65 @@ error TS2318: Cannot find global type 'IterableIterator'.
 
     // Not erasable
     (()=><any>{})();
+         ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     (()=>< any >{})();
+         ~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     (()=> < any > {})();
+          ~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
     // Erasable
     (()=><any>({}))();
+         ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     (()=>(<any>{}))();
+          ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     <any>{};
+    ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
 
     // return and yield ASI
     function *gen() {
         yield <any>
+              ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
             1;
         return <any>
+               ~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
             1;
     }
 
     // at the start of an ExpressionStatement if followed by an object literal; though I'm not sure why one would use it there
     <unknown>{foo() {}}.foo();
+    ~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
     // at the start of an ExpressionStatement if followed by function keyword
     <unknown>function() {}();
+    ~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     <unknown>function() {};
+    ~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
     // at the start of an ExpressionStatement if followed by an anonymous class expression
     // note that this exact syntax currently emits invalid JS (no parenthesis added like for function above)
     <unknown>class {}
+    ~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
-==== commonjs.cts (0 errors) ====
+==== commonjs.cts (2 errors) ====
     import foo = require("./other.cjs");
+    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
     export = foo;
+    ~~~~~~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
 
 ==== other.d.cts (0 errors) ====

testdata/baselines/reference/submodule/compiler/erasableSyntaxOnly2.errors.txt

@@ -1,15 +1,24 @@
+index.ts(1,10): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 index.ts(1,19): error TS1005: '>' expected.
+index.ts(2,9): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 index.ts(2,18): error TS1005: '>' expected.
+index.ts(3,9): error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 index.ts(3,17): error TS1005: '>' expected.
 
 
-==== index.ts (3 errors) ====
+==== index.ts (6 errors) ====
     let a = (<unknown function foo() {});
+             ~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
                       ~~~~~~~~
 !!! error TS1005: '>' expected.
     let b = <unknown 123;
+            ~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
                      ~~~
 !!! error TS1005: '>' expected.
     let c = <unknown
+            ~~~~~~~~
+!!! error TS1294: This syntax is not allowed when 'erasableSyntaxOnly' is enabled.
 
 !!! error TS1005: '>' expected.