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proc_macro: Improve Debug representations
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This commit improves the `fmt::Debug` output of `proc_macro` data structures by
primarily focusing on the representation exposed by `proc_macro` rather than the
compiler's own internal representation. This cuts down quite a bit on assorted
wrapper types and ensure a relatively clean output.

Closes #49720
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@alexcrichton
alexcrichton committed Apr 6, 2018
1 parent a143462 commit 6c08bb8
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Showing 2 changed files with 63 additions and 35 deletions.
83 changes: 57 additions & 26 deletions src/libproc_macro/lib.rs
View file
Expand Up @@ -127,7 +127,8 @@ impl fmt::Display for TokenStream {
#[stable(feature = "proc_macro_lib", since = "1.15.0")]
impl fmt::Debug for TokenStream {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
f.write_str("TokenStream ")?;
f.debug_list().entries(self.clone()).finish()
}
}

Expand Down Expand Up @@ -222,7 +223,7 @@ pub fn quote_span(span: Span) -> TokenStream {

/// A region of source code, along with macro expansion information.
#[unstable(feature = "proc_macro", issue = "38356")]
#[derive(Copy, Clone, Debug)]
#[derive(Copy, Clone)]
pub struct Span(syntax_pos::Span);

macro_rules! diagnostic_method {
Expand Down Expand Up @@ -334,6 +335,16 @@ impl Span {
diagnostic_method!(help, Level::Help);
}

#[unstable(feature = "proc_macro", issue = "38356")]
impl fmt::Debug for Span {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{:?} bytes({}...{})",
self.0.ctxt(),
self.0.lo().0,
self.0.hi().0)
}
}

/// A line-column pair representing the start or end of a `Span`.
#[unstable(feature = "proc_macro", issue = "38356")]
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
Expand Down Expand Up @@ -422,7 +433,7 @@ impl PartialEq<FileName> for SourceFile {

/// A single token or a delimited sequence of token trees (e.g. `[1, (), ..]`).
#[unstable(feature = "proc_macro", issue = "38356")]
#[derive(Clone, Debug)]
#[derive(Clone)]
pub enum TokenTree {
/// A delimited tokenstream
Group(Group),
Expand Down Expand Up @@ -463,6 +474,20 @@ impl TokenTree {
}
}

#[unstable(feature = "proc_macro", issue = "38356")]
impl fmt::Debug for TokenTree {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
// Each of these has the name in the struct type in the derived debug,
// so don't bother with an extra layer of indirection
match *self {
TokenTree::Group(ref tt) => tt.fmt(f),
TokenTree::Term(ref tt) => tt.fmt(f),
TokenTree::Op(ref tt) => tt.fmt(f),
TokenTree::Literal(ref tt) => tt.fmt(f),
}
}
}

#[unstable(feature = "proc_macro", issue = "38356")]
impl From<Group> for TokenTree {
fn from(g: Group) -> TokenTree {
Expand Down Expand Up @@ -717,7 +742,8 @@ impl fmt::Display for Term {
#[derive(Clone, Debug)]
#[unstable(feature = "proc_macro", issue = "38356")]
pub struct Literal {
token: token::Token,
lit: token::Lit,
suffix: Option<ast::Name>,
span: Span,
}

Expand All @@ -734,10 +760,9 @@ macro_rules! suffixed_int_literals {
/// below.
#[unstable(feature = "proc_macro", issue = "38356")]
pub fn $name(n: $kind) -> Literal {
let lit = token::Lit::Integer(Symbol::intern(&n.to_string()));
let ty = Some(Symbol::intern(stringify!($kind)));
Literal {
token: token::Literal(lit, ty),
lit: token::Lit::Integer(Symbol::intern(&n.to_string())),
suffix: Some(Symbol::intern(stringify!($kind))),
span: Span::call_site(),
}
}
Expand All @@ -759,9 +784,9 @@ macro_rules! unsuffixed_int_literals {
/// below.
#[unstable(feature = "proc_macro", issue = "38356")]
pub fn $name(n: $kind) -> Literal {
let lit = token::Lit::Integer(Symbol::intern(&n.to_string()));
Literal {
token: token::Literal(lit, None),
lit: token::Lit::Integer(Symbol::intern(&n.to_string())),
suffix: None,
span: Span::call_site(),
}
}
Expand Down Expand Up @@ -814,9 +839,9 @@ impl Literal {
if !n.is_finite() {
panic!("Invalid float literal {}", n);
}
let lit = token::Lit::Float(Symbol::intern(&n.to_string()));
Literal {
token: token::Literal(lit, None),
lit: token::Lit::Float(Symbol::intern(&n.to_string())),
suffix: None,
span: Span::call_site(),
}
}
Expand All @@ -837,9 +862,9 @@ impl Literal {
if !n.is_finite() {
panic!("Invalid float literal {}", n);
}
let lit = token::Lit::Float(Symbol::intern(&n.to_string()));
Literal {
token: token::Literal(lit, Some(Symbol::intern("f32"))),
lit: token::Lit::Float(Symbol::intern(&n.to_string())),
suffix: Some(Symbol::intern("f32")),
span: Span::call_site(),
}
}
Expand All @@ -859,9 +884,9 @@ impl Literal {
if !n.is_finite() {
panic!("Invalid float literal {}", n);
}
let lit = token::Lit::Float(Symbol::intern(&n.to_string()));
Literal {
token: token::Literal(lit, None),
lit: token::Lit::Float(Symbol::intern(&n.to_string())),
suffix: None,
span: Span::call_site(),
}
}
Expand All @@ -882,9 +907,9 @@ impl Literal {
if !n.is_finite() {
panic!("Invalid float literal {}", n);
}
let lit = token::Lit::Float(Symbol::intern(&n.to_string()));
Literal {
token: token::Literal(lit, Some(Symbol::intern("f64"))),
lit: token::Lit::Float(Symbol::intern(&n.to_string())),
suffix: Some(Symbol::intern("f64")),
span: Span::call_site(),
}
}
Expand All @@ -897,7 +922,8 @@ impl Literal {
escaped.extend(ch.escape_debug());
}
Literal {
token: token::Literal(token::Lit::Str_(Symbol::intern(&escaped)), None),
lit: token::Lit::Str_(Symbol::intern(&escaped)),
suffix: None,
span: Span::call_site(),
}
}
Expand All @@ -908,7 +934,8 @@ impl Literal {
let mut escaped = String::new();
escaped.extend(ch.escape_unicode());
Literal {
token: token::Literal(token::Lit::Char(Symbol::intern(&escaped)), None),
lit: token::Lit::Char(Symbol::intern(&escaped)),
suffix: None,
span: Span::call_site(),
}
}
Expand All @@ -919,7 +946,8 @@ impl Literal {
let string = bytes.iter().cloned().flat_map(ascii::escape_default)
.map(Into::<char>::into).collect::<String>();
Literal {
token: token::Literal(token::Lit::ByteStr(Symbol::intern(&string)), None),
lit: token::Lit::ByteStr(Symbol::intern(&string)),
suffix: None,
span: Span::call_site(),
}
}
Expand Down Expand Up @@ -1055,7 +1083,7 @@ impl TokenTree {
Ident(ident, true) => {
tt!(Term::new(&format!("r#{}", ident), Span(span)))
}
Literal(..) => tt!(self::Literal { token, span: Span(span) }),
Literal(lit, suffix) => tt!(self::Literal { lit, suffix, span: Span(span) }),
DocComment(c) => {
let style = comments::doc_comment_style(&c.as_str());
let stripped = comments::strip_doc_comment_decoration(&c.as_str());
Expand Down Expand Up @@ -1111,33 +1139,36 @@ impl TokenTree {
return TokenTree::Token(tt.span.0, token).into();
}
self::TokenTree::Literal(self::Literal {
token: Literal(Lit::Integer(ref a), b),
lit: Lit::Integer(ref a),
suffix,
span,
})
if a.as_str().starts_with("-") =>
{
let minus = BinOp(BinOpToken::Minus);
let integer = Symbol::intern(&a.as_str()[1..]);
let integer = Literal(Lit::Integer(integer), b);
let integer = Literal(Lit::Integer(integer), suffix);
let a = TokenTree::Token(span.0, minus);
let b = TokenTree::Token(span.0, integer);
return vec![a, b].into_iter().collect()
}
self::TokenTree::Literal(self::Literal {
token: Literal(Lit::Float(ref a), b),
lit: Lit::Float(ref a),
suffix,
span,
})
if a.as_str().starts_with("-") =>
{
let minus = BinOp(BinOpToken::Minus);
let float = Symbol::intern(&a.as_str()[1..]);
let float = Literal(Lit::Float(float), b);
let float = Literal(Lit::Float(float), suffix);
let a = TokenTree::Token(span.0, minus);
let b = TokenTree::Token(span.0, float);
return vec![a, b].into_iter().collect()
}
self::TokenTree::Literal(tt) => {
return TokenTree::Token(tt.span.0, tt.token).into()
let token = Literal(tt.lit, tt.suffix);
return TokenTree::Token(tt.span.0, token).into()
}
};

Expand Down
15 changes: 6 additions & 9 deletions src/libproc_macro/quote.rs
View file
Expand Up @@ -208,13 +208,15 @@ macro_rules! literals {
match self {
$(LiteralKind::$i => {
Literal {
token: token::Literal(token::Lit::$i(sym), suffix),
lit: token::Lit::$i(sym),
suffix,
span: contents.span,
}
})*
$(LiteralKind::$raw(n) => {
Literal {
token: token::Literal(token::Lit::$raw(sym, n), suffix),
lit: token::Lit::$raw(sym, n),
suffix,
span: contents.span,
}
})*
Expand All @@ -224,16 +226,11 @@ macro_rules! literals {

impl Literal {
fn kind_contents_and_suffix(self) -> (LiteralKind, Term, Option<Term>) {
let (lit, suffix) = match self.token {
token::Literal(lit, suffix) => (lit, suffix),
_ => panic!("unsupported literal {:?}", self.token),
};

let (kind, contents) = match lit {
let (kind, contents) = match self.lit {
$(token::Lit::$i(contents) => (LiteralKind::$i, contents),)*
$(token::Lit::$raw(contents, n) => (LiteralKind::$raw(n), contents),)*
};
let suffix = suffix.map(|sym| Term::new(&sym.as_str(), self.span()));
let suffix = self.suffix.map(|sym| Term::new(&sym.as_str(), self.span()));
(kind, Term::new(&contents.as_str(), self.span()), suffix)
}
}
Expand Down

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