Legal JS is interpreted incorrectly in the presence of certain keywords

[DanielRosenwasser]

Take the following code.

var type;
var string;
var Foo;

type Foo = string;

Now add a newline between type Foo:

var type;
var string;
var Foo;

type
Foo = string;

Still valid, but should have a completely different meaning now. In the first, we have a type alias, while in the second, we have a lone identifier and a declaration.

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Here's actually a few contexts where we do the wrong thing:

• type aliases (see the example above)
• namespaces/internal modules:

namespace // this is the identifier 'namespace'
m // this is the identifier 'm'
{ } // this is a block body

• declared modules

declare // this is the identifier 'declare'
module // this is the identifier 'module'
"my external module" // this is just a string
{ } // this is a block body