1 use rustc_errors::{Applicability, DiagnosticBuilder};
3 use rustc_ast::ast::{self, *};
5 use rustc_ast::token::{self, TokenKind};
6 use rustc_ast::tokenstream::{DelimSpan, TokenStream, TokenTree};
7 use rustc_ast_pretty::pprust;
8 use rustc_expand::base::*;
9 use rustc_parse::parser::Parser;
10 use rustc_span::symbol::{sym, Ident, Symbol};
11 use rustc_span::{Span, DUMMY_SP};
13 pub fn expand_assert<'cx>(
14 cx: &'cx mut ExtCtxt<'_>,
17 ) -> Box<dyn MacResult + 'cx> {
18 let Assert { cond_expr, custom_message } = match parse_assert(cx, sp, tts) {
22 return DummyResult::any(sp);
26 // `core::panic` and `std::panic` are different macros, so we use call-site
27 // context to pick up whichever is currently in scope.
28 let sp = cx.with_call_site_ctxt(sp);
29 let tokens = custom_message.unwrap_or_else(|| {
30 TokenStream::from(TokenTree::token(
33 Symbol::intern(&format!(
34 "assertion failed: {}",
35 pprust::expr_to_string(&cond_expr).escape_debug()
42 let args = P(MacArgs::Delimited(DelimSpan::from_single(sp), MacDelimiter::Parenthesis, tokens));
43 let panic_call = MacCall {
44 path: Path::from_ident(Ident::new(sym::panic, sp)),
46 prior_type_ascription: None,
48 let if_expr = cx.expr_if(
50 cx.expr(sp, ExprKind::Unary(UnOp::Not, cond_expr)),
51 cx.expr(sp, ExprKind::MacCall(panic_call)),
54 MacEager::expr(if_expr)
58 cond_expr: P<ast::Expr>,
59 custom_message: Option<TokenStream>,
66 ) -> Result<Assert, DiagnosticBuilder<'a>> {
67 let mut parser = cx.new_parser_from_tts(stream);
69 if parser.token == token::Eof {
70 let mut err = cx.struct_span_err(sp, "macro requires a boolean expression as an argument");
71 err.span_label(sp, "boolean expression required");
75 let cond_expr = parser.parse_expr()?;
77 // Some crates use the `assert!` macro in the following form (note extra semicolon):
83 // Emit an error about semicolon and suggest removing it.
84 if parser.token == token::Semi {
85 let mut err = cx.struct_span_err(sp, "macro requires an expression as an argument");
88 "try removing semicolon",
90 Applicability::MaybeIncorrect,
97 // Some crates use the `assert!` macro in the following form (note missing comma before
100 // assert!(true "error message");
102 // Emit an error and suggest inserting a comma.
104 if let token::Literal(token::Lit { kind: token::Str, .. }) = parser.token.kind {
105 let mut err = cx.struct_span_err(parser.token.span, "unexpected string literal");
106 let comma_span = parser.prev_token.span.shrink_to_hi();
107 err.span_suggestion_short(
109 "try adding a comma",
111 Applicability::MaybeIncorrect,
115 parse_custom_message(&mut parser)
116 } else if parser.eat(&token::Comma) {
117 parse_custom_message(&mut parser)
122 if parser.token != token::Eof {
123 parser.expect_one_of(&[], &[])?;
127 Ok(Assert { cond_expr, custom_message })
130 fn parse_custom_message(parser: &mut Parser<'_>) -> Option<TokenStream> {
131 let ts = parser.parse_tokens();
132 if !ts.is_empty() { Some(ts) } else { None }