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Remove unreachable! from macros.rs

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replaced unreachable! with error handling using Option.

Closes #2558
This commit is contained in:
codeworm96 2018-03-28 23:38:34 +08:00
parent 0f55350c7d
commit e68682f6db
1 changed files with 12 additions and 10 deletions
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22
src/macros.rs
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@ -687,7 +687,7 @@ impl MacroArgParser {
self.buf.clear();
}
fn add_meta_variable(&mut self, iter: &mut Cursor) {
fn add_meta_variable(&mut self, iter: &mut Cursor) -> Option<()> {
match iter.next() {
Some(TokenTree::Token(sp, Token::Ident(ref ident))) => {
self.result.push(ParsedMacroArg {
@ -697,8 +697,9 @@ impl MacroArgParser {
self.buf.clear();
self.is_meta_var = false;
Some(())
}
_ => unreachable!(),
_ => None,
}
}
@ -716,7 +717,7 @@ impl MacroArgParser {
delim: DelimToken,
iter: &mut Cursor,
span: Span,
) {
) -> Option<()> {
let mut buffer = String::new();
let mut first = false;
let mut lo = span.lo();
@ -740,7 +741,7 @@ impl MacroArgParser {
buffer.push_str(&pprust::token_to_string(t));
hi = sp.hi();
}
_ => unreachable!(),
_ => return None,
}
}
@ -758,6 +759,7 @@ impl MacroArgParser {
kind: MacroArgKind::Repeat(delim, inner, another, self.last_tok.clone()),
span: mk_sp(self.lo, self.hi),
});
Some(())
}
fn update_buffer(&mut self, lo: BytePos, t: &Token) {
@ -802,7 +804,7 @@ impl MacroArgParser {
}
/// Returns a collection of parsed macro def's arguments.
pub fn parse(mut self, tokens: ThinTokenStream) -> Vec<ParsedMacroArg> {
pub fn parse(mut self, tokens: ThinTokenStream) -> Option<Vec<ParsedMacroArg>> {
let mut iter = (tokens.into(): TokenStream).trees();
while let Some(ref tok) = iter.next() {
@ -819,7 +821,7 @@ impl MacroArgParser {
self.start_tok = Token::Dollar;
}
TokenTree::Token(_, Token::Colon) if self.is_meta_var => {
self.add_meta_variable(&mut iter);
self.add_meta_variable(&mut iter)?;
}
TokenTree::Token(sp, ref t) => self.update_buffer(sp.lo(), t),
TokenTree::Delimited(sp, delimited) => {
@ -834,10 +836,10 @@ impl MacroArgParser {
// Parse the stuff inside delimiters.
let mut parser = MacroArgParser::new();
parser.lo = sp.lo();
let delimited_arg = parser.parse(delimited.tts.clone());
let delimited_arg = parser.parse(delimited.tts.clone())?;
if self.is_meta_var {
self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp);
self.add_repeat(delimited_arg, delimited.delim, &mut iter, *sp)?;
} else {
self.add_delimited(delimited_arg, delimited.delim, *sp);
}
@ -853,7 +855,7 @@ impl MacroArgParser {
self.add_other();
}
self.result
Some(self.result)
}
}
@ -915,7 +917,7 @@ fn format_macro_args(
toks: ThinTokenStream,
shape: Shape,
) -> Option<String> {
let parsed_args = MacroArgParser::new().parse(toks);
let parsed_args = MacroArgParser::new().parse(toks)?;
wrap_macro_args(context, &parsed_args, shape)
}