Better error for wrong return (: vs =>) in types
Better error for wrong return (: vs =>) in types

It's very ambiguous in expression position, so impossible to give a
better message from the parser. For example:

let f = (x: number) => number => x + 1;
                    ~~
                    Should be ':'

But the parser doesn't know that 'number' isn't an expression now.

donaldpipowitch/TypeScript,synaptek/TypeScript,kpreisser/TypeScript,alexeagle/TypeScript,synaptek/TypeScript,kpreisser/TypeScript,weswigham/TypeScript,RyanCavanaugh/TypeScript,Microsoft/TypeScript,microsoft/TypeScript,Eyas/TypeScript,TukekeSoft/TypeScript,SaschaNaz/TypeScript,nojvek/TypeScript,minestarks/TypeScript,microsoft/TypeScript,nojvek/TypeScript,basarat/TypeScript,basarat/TypeScript,TukekeSoft/TypeScript,TukekeSoft/TypeScript,SaschaNaz/TypeScript,Eyas/TypeScript,donaldpipowitch/TypeScript,chuckjaz/TypeScript,basarat/TypeScript,basarat/TypeScript,SaschaNaz/TypeScript,Microsoft/TypeScript,weswigham/TypeScript,synaptek/TypeScript,minestarks/TypeScript,synaptek/TypeScript,weswigham/TypeScript,Microsoft/TypeScript,Eyas/TypeScript,chuckjaz/TypeScript,donaldpipowitch/TypeScript,microsoft/TypeScript,chuckjaz/TypeScript,minestarks/TypeScript,SaschaNaz/TypeScript,nojvek/TypeScript,nojvek/TypeScript,kpreisser/TypeScript,alexeagle/TypeScript,RyanCavanaugh/TypeScript,RyanCavanaugh/TypeScript,donaldpipowitch/TypeScript,chuckjaz/TypeScript,kitsonk/TypeScript,alexeagle/TypeScript,kitsonk/TypeScript,Eyas/TypeScript,kitsonk/TypeScript