rust/tests/ui/did_you_mean/issue-49746-unicode-confusable-in-float-literal-expt.rs

const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
//~^ ERROR expected at least one digit in exponent
//~| ERROR unknown start of token: \u{2212}
//~| ERROR cannot subtract `{integer}` from `{float}`

fn main() {}
-												Fix test

											
										
										
											2018-05-26 04:57:02 +00:00
+								const UNIVERSAL_GRAVITATIONAL_CONSTANT: f64 = 6.674e−11; // m³⋅kg⁻¹⋅s⁻²
-												in which we check for confusable Unicodepoints in float literal exponent

The `FatalError.raise()` might seem unmotivated (in most places in
the compiler, `err.emit()` suffices), but it's actually used to
maintain behavior (viz., stop lexing, don't emit potentially spurious
errors looking for the next token after the bad Unicodepoint in the
exponent): the previous revision's `self.err_span_` ultimately calls
`Handler::emit`, which aborts if the `Handler`'s continue_after_error
flag is set, which seems to typically be true during lexing (see
`phase_1_parse_input` and and how `CompileController::basic` has
`continue_parse_after_error: false` in librustc_driver).

Also, let's avoid apostrophes in error messages (the present author
would argue that users expect a reassuringly detached, formal,
above-it-all tone from a Serious tool like a compiler), and use an
RLS-friendly structured suggestion.

Resolves #49746.

											
										
										
											2018-04-15 21:30:23 +00:00
+								//~^ ERROR expected at least one digit in exponent
-												Introduce rustc_lexer

The idea here is to make a reusable library out of the existing
rust-lexer, by separating out pure lexing and rustc-specific concerns,
like spans, error reporting an interning.

So, rustc_lexer operates directly on `&str`, produces simple tokens
which are a pair of type-tag and a bit of original text, and does not
report errors, instead storing them as flags on the token.

											
										
										
											2019-05-06 08:53:40 +00:00
+								//~| ERROR unknown start of token: \u{2212}
-												Allow lexer to recover from some homoglyphs

											
										
										
											2019-07-24 23:10:42 +00:00
+								//~| ERROR cannot subtract `{integer}` from `{float}`
-												in which we check for confusable Unicodepoints in float literal exponent

The `FatalError.raise()` might seem unmotivated (in most places in
the compiler, `err.emit()` suffices), but it's actually used to
maintain behavior (viz., stop lexing, don't emit potentially spurious
errors looking for the next token after the bad Unicodepoint in the
exponent): the previous revision's `self.err_span_` ultimately calls
`Handler::emit`, which aborts if the `Handler`'s continue_after_error
flag is set, which seems to typically be true during lexing (see
`phase_1_parse_input` and and how `CompileController::basic` has
`continue_parse_after_error: false` in librustc_driver).

Also, let's avoid apostrophes in error messages (the present author
would argue that users expect a reassuringly detached, formal,
above-it-all tone from a Serious tool like a compiler), and use an
RLS-friendly structured suggestion.

Resolves #49746.

											
										
										
											2018-04-15 21:30:23 +00:00
 								fn main() {}