diff --git a/src/compiler/checker.ts b/src/compiler/checker.ts
index 5a2561e81ed..a860c037c89 100644
--- a/src/compiler/checker.ts
+++ b/src/compiler/checker.ts
@@ -30594,9 +30594,9 @@ namespace ts {
                 if (node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement) {
                     checkVarDeclaredNamesNotShadowed(node);
                 }
-                checkCollisionWithRequireExportsInGeneratedCode(node, <Identifier>node.name);
-                checkCollisionWithGlobalPromiseInGeneratedCode(node, <Identifier>node.name);
-                if (!compilerOptions.noEmit && languageVersion < ScriptTarget.ESNext && needCollisionCheckForIdentifier(node, node.name as Identifier, "WeakMap")) {
+                checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
+                checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
+                if (!compilerOptions.noEmit && languageVersion < ScriptTarget.ESNext && needCollisionCheckForIdentifier(node, node.name, "WeakMap")) {
                     potentialWeakMapCollisions.push(node);
                 }
             }
@@ -35856,10 +35856,10 @@ namespace ts {
                     node.kind === SyntaxKind.FunctionExpression ||
                     node.kind === SyntaxKind.MethodDeclaration);
                 if (node.flags & NodeFlags.Ambient) {
-                    return grammarErrorOnNode(node.asteriskToken!, Diagnostics.Generators_are_not_allowed_in_an_ambient_context);
+                    return grammarErrorOnNode(node.asteriskToken, Diagnostics.Generators_are_not_allowed_in_an_ambient_context);
                 }
                 if (!node.body) {
-                    return grammarErrorOnNode(node.asteriskToken!, Diagnostics.An_overload_signature_cannot_be_declared_as_a_generator);
+                    return grammarErrorOnNode(node.asteriskToken, Diagnostics.An_overload_signature_cannot_be_declared_as_a_generator);
                 }
             }
         }