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ast: Remove some indirection layers from values in key-value attributes

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This commit is contained in:
Vadim Petrochenkov 2020-12-19 23:38:22 +03:00
parent ef589490a7
commit 71cd6f42a6
12 changed files with 72 additions and 50 deletions
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34
compiler/rustc_ast_lowering/src/lib.rs
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@ -1013,10 +1013,36 @@ impl<'a, 'hir> LoweringContext<'a, 'hir> {
// This is an inert key-value attribute - it will never be visible to macros
// after it gets lowered to HIR. Therefore, we can synthesize tokens with fake
// spans to handle nonterminals in `#[doc]` (e.g. `#[doc = $e]`).
MacArgs::Eq(eq_span, ref tokens) => MacArgs::Eq(
eq_span,
self.lower_token_stream(tokens.clone(), CanSynthesizeMissingTokens::Yes),
),
MacArgs::Eq(eq_span, ref token) => {
// In valid code the value is always representable as a single literal token.
fn unwrap_single_token(sess: &Session, tokens: TokenStream, span: Span) -> Token {
if tokens.len() != 1 {
sess.diagnostic()
.delay_span_bug(span, "multiple tokens in key-value attribute's value");
}
match tokens.into_trees().next() {
Some(TokenTree::Token(token)) => token,
Some(TokenTree::Delimited(_, delim, tokens)) => {
if delim != token::NoDelim {
sess.diagnostic().delay_span_bug(
span,
"unexpected delimiter in key-value attribute's value",
)
}
unwrap_single_token(sess, tokens, span)
}
None => Token::dummy(),
}
}
let tokens = TokenStreamLowering {
parse_sess: &self.sess.parse_sess,
synthesize_tokens: CanSynthesizeMissingTokens::Yes,
nt_to_tokenstream: self.nt_to_tokenstream,
}
.lower_token(token.clone());
MacArgs::Eq(eq_span, unwrap_single_token(self.sess, tokens, token.span))
}
}
}