fix issue-144595

[bb1yd]

relevant issue:#144595
I implement this issue by simply find every colon in the tuple struct.

This method has a problem that it might mislead the user when the user type something likestruct Foo(std::string:String); (accidentally type :: as :). The compiler will print:

help: if you wanted to create a tuple struct, remove field names:
 --> test.rs:3:21
  |
3 |     struct Foo(std::string:String);
  |                     -------

I'm not sure if this is acceptable. Maybe a better way is to parse the field as a record struct field again.

[bb1yd]

r? compiler

[bb1yd]

@rustbot ready

[rustbot]

The parser was modified, potentially altering the grammar of (stable) Rust
which would be a breaking change.

cc @fmease

[bb1yd]

too messy

new PR:#156545