Improve the existing fix-the-AST code to better identify the
expression following the "go" or "defer" keywords:
- Don't slurp the expression start outside the loop since the
expression might only have a single token.
- Set expression end to the position after the final token, not the
position of the final token.
- Track curly brace nesting to properly capture an entire "func() {}"
expression.
- Fix parent node detection to work when BadStmt isn't first statement
of block.
- Add special case to detect dangling period, e.g. "defer fmt.". We
insert phantom "_" selectors like go/parser does to prevent the
dangling "." from messing up the AST.
- Use reflect in offsetPositions so it updates positions in all node
types. This code shouldn't be called often, so I don't think
performance is a concern.
I also tweaked the function snippet code so it properly expands
"defer" and "go" expressions to function calls. It thought it didn't
have to expand since there was already a *ast.CallExpr, but the
CallExpr was faked by us and the source doesn't actually contain the
"()" calling parens.
Note that this does not work for nested go/defer statements. For
example, completions won't work properly in cases like this:
go func() {
defer fmt.<>
}
I think we can fix this as well with some more work.
Change-Id: I8f9753fda76909b0e3a83489cdea69ad04ee237a
Reviewed-on: https://go-review.googlesource.com/c/tools/+/193997
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
Run-TryBot: Rebecca Stambler <rstambler@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
