      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

    // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
    // file at the top-level directory of this distribution and at
    // http://rust-lang.org/COPYRIGHT.
    //
    // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
    // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
    // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
    // option. This file may not be copied, modified, or distributed
    // except according to those terms.

    use Span;

    use rustc_errors as errors;
    use syntax_pos::MultiSpan;

    /// An enum representing a diagnostic level.
    #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
    #[derive(Copy, Clone, Debug)]
    pub enum Level {
        /// An error.
        Error,
        /// A warning.
        Warning,
        /// A note.
        Note,
        /// A help message.
        Help,
        #[doc(hidden)]
        __Nonexhaustive,
    }

    /// A structure representing a diagnostic message and associated children
    /// messages.
    #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
    #[derive(Clone, Debug)]
    pub struct Diagnostic {
        level: Level,
        message: String,
        span: Option<Span>,
        children: Vec<Diagnostic>
    }

    macro_rules! diagnostic_child_methods {
        ($spanned:ident, $regular:ident, $level:expr) => (
            /// Add a new child diagnostic message to `self` with the level
            /// identified by this methods name with the given `span` and `message`.
            #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
            pub fn $spanned<T: Into<String>>(mut self, span: Span, message: T) -> Diagnostic {
                self.children.push(Diagnostic::spanned(span, $level, message));
                self
            }

            /// Add a new child diagnostic message to `self` with the level
            /// identified by this method's name with the given `message`.
            #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
            pub fn $regular<T: Into<String>>(mut self, message: T) -> Diagnostic {
                self.children.push(Diagnostic::new($level, message));
                self
            }
        )
    }

    impl Diagnostic {
        /// Create a new diagnostic with the given `level` and `message`.
        #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
        pub fn new<T: Into<String>>(level: Level, message: T) -> Diagnostic {
            Diagnostic {
                level: level,
                message: message.into(),
                span: None,
                children: vec![]
            }
        }

        /// Create a new diagnostic with the given `level` and `message` pointing to
        /// the given `span`.
        #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
        pub fn spanned<T: Into<String>>(span: Span, level: Level, message: T) -> Diagnostic {
            Diagnostic {
                level: level,
                message: message.into(),
                span: Some(span),
                children: vec![]
            }
        }

        diagnostic_child_methods!(span_error, error, Level::Error);
        diagnostic_child_methods!(span_warning, warning, Level::Warning);
        diagnostic_child_methods!(span_note, note, Level::Note);
        diagnostic_child_methods!(span_help, help, Level::Help);

        /// Returns the diagnostic `level` for `self`.
        #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
        pub fn level(&self) -> Level {
            self.level
        }

        /// Emit the diagnostic.
        #[unstable(feature = "proc_macro_diagnostic", issue = "38356")]
        pub fn emit(self) {
            let level = self.level.to_internal();
            let mut diag = errors::Diagnostic::new(level, &*self.message);

            if let Some(span) = self.span {
                diag.set_span(span.0);
            }

            for child in self.children {
                let span = child.span.map_or(MultiSpan::new(), |s| s.0.into());
                let level = child.level.to_internal();
                diag.sub(level, &*child.message, span, None);
            }

            ::__internal::with_sess(move |sess, _| {
                errors::DiagnosticBuilder::new_diagnostic(&sess.span_diagnostic, diag).emit();
            });
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g. `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g. `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g. `str,u8` or `String,struct:Vec,test`)