1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
mod context;
use crate::edition_panic::use_panic_2021;
use crate::errors;
use rustc_ast::ptr::P;
use rustc_ast::token;
use rustc_ast::tokenstream::{DelimSpan, TokenStream};
use rustc_ast::{DelimArgs, Expr, ExprKind, MacCall, MacDelimiter, Path, PathSegment, UnOp};
use rustc_ast_pretty::pprust;
use rustc_errors::PResult;
use rustc_expand::base::{DummyResult, ExtCtxt, MacEager, MacResult};
use rustc_parse::parser::Parser;
use rustc_span::symbol::{sym, Ident, Symbol};
use rustc_span::{Span, DUMMY_SP};
use thin_vec::thin_vec;
pub fn expand_assert<'cx>(
cx: &'cx mut ExtCtxt<'_>,
span: Span,
tts: TokenStream,
) -> Box<dyn MacResult + 'cx> {
let Assert { cond_expr, custom_message } = match parse_assert(cx, span, tts) {
Ok(assert) => assert,
Err(mut err) => {
err.emit();
return DummyResult::any(span);
}
};
// `core::panic` and `std::panic` are different macros, so we use call-site
// context to pick up whichever is currently in scope.
let call_site_span = cx.with_call_site_ctxt(span);
let panic_path = || {
if use_panic_2021(span) {
// On edition 2021, we always call `$crate::panic::panic_2021!()`.
Path {
span: call_site_span,
segments: cx
.std_path(&[sym::panic, sym::panic_2021])
.into_iter()
.map(|ident| PathSegment::from_ident(ident))
.collect(),
tokens: None,
}
} else {
// Before edition 2021, we call `panic!()` unqualified,
// such that it calls either `std::panic!()` or `core::panic!()`.
Path::from_ident(Ident::new(sym::panic, call_site_span))
}
};
// Simply uses the user provided message instead of generating custom outputs
let expr = if let Some(tokens) = custom_message {
let then = cx.expr(
call_site_span,
ExprKind::MacCall(P(MacCall {
path: panic_path(),
args: P(DelimArgs {
dspan: DelimSpan::from_single(call_site_span),
delim: MacDelimiter::Parenthesis,
tokens,
}),
prior_type_ascription: None,
})),
);
expr_if_not(cx, call_site_span, cond_expr, then, None)
}
// If `generic_assert` is enabled, generates rich captured outputs
//
// FIXME(c410-f3r) See https://github.com/rust-lang/rust/issues/96949
else if let Some(features) = cx.ecfg.features && features.generic_assert {
context::Context::new(cx, call_site_span).build(cond_expr, panic_path())
}
// If `generic_assert` is not enabled, only outputs a literal "assertion failed: ..."
// string
else {
// Pass our own message directly to $crate::panicking::panic(),
// because it might contain `{` and `}` that should always be
// passed literally.
let then = cx.expr_call_global(
call_site_span,
cx.std_path(&[sym::panicking, sym::panic]),
thin_vec![cx.expr_str(
DUMMY_SP,
Symbol::intern(&format!(
"assertion failed: {}",
pprust::expr_to_string(&cond_expr).escape_debug()
)),
)],
);
expr_if_not(cx, call_site_span, cond_expr, then, None)
};
MacEager::expr(expr)
}
struct Assert {
cond_expr: P<Expr>,
custom_message: Option<TokenStream>,
}
// if !{ ... } { ... } else { ... }
fn expr_if_not(
cx: &ExtCtxt<'_>,
span: Span,
cond: P<Expr>,
then: P<Expr>,
els: Option<P<Expr>>,
) -> P<Expr> {
cx.expr_if(span, cx.expr(span, ExprKind::Unary(UnOp::Not, cond)), then, els)
}
fn parse_assert<'a>(cx: &mut ExtCtxt<'a>, sp: Span, stream: TokenStream) -> PResult<'a, Assert> {
let mut parser = cx.new_parser_from_tts(stream);
if parser.token == token::Eof {
return Err(cx.create_err(errors::AssertRequiresBoolean { span: sp }));
}
let cond_expr = parser.parse_expr()?;
// Some crates use the `assert!` macro in the following form (note extra semicolon):
//
// assert!(
// my_function();
// );
//
// Emit an error about semicolon and suggest removing it.
if parser.token == token::Semi {
cx.emit_err(errors::AssertRequiresExpression { span: sp, token: parser.token.span });
parser.bump();
}
// Some crates use the `assert!` macro in the following form (note missing comma before
// message):
//
// assert!(true "error message");
//
// Emit an error and suggest inserting a comma.
let custom_message =
if let token::Literal(token::Lit { kind: token::Str, .. }) = parser.token.kind {
let comma = parser.prev_token.span.shrink_to_hi();
cx.emit_err(errors::AssertMissingComma { span: parser.token.span, comma });
parse_custom_message(&mut parser)
} else if parser.eat(&token::Comma) {
parse_custom_message(&mut parser)
} else {
None
};
if parser.token != token::Eof {
return parser.unexpected();
}
Ok(Assert { cond_expr, custom_message })
}
fn parse_custom_message(parser: &mut Parser<'_>) -> Option<TokenStream> {
let ts = parser.parse_tokens();
if !ts.is_empty() { Some(ts) } else { None }
}
|
