Remove "unnecessary" type assertions.

Author: DanielRosenwasser

src/compiler/checker.ts

@@ -30102,8 +30102,8 @@ namespace ts {
                 if (node.kind === SyntaxKind.VariableDeclaration || node.kind === SyntaxKind.BindingElement) {
                     checkVarDeclaredNamesNotShadowed(node);
                 }
-                checkCollisionWithRequireExportsInGeneratedCode(node, <Identifier>node.name);
-                checkCollisionWithGlobalPromiseInGeneratedCode(node, <Identifier>node.name);
+                checkCollisionWithRequireExportsInGeneratedCode(node, node.name);
+                checkCollisionWithGlobalPromiseInGeneratedCode(node, node.name);
             }
         }
 
@@ -35268,10 +35268,10 @@ 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);
                 }
             }
         }