# 1.29.0[−][src]Struct proc_macro::Span

    pub struct Span(_);

A region of source code, along with macro expansion information.

## Methods

### `impl Span`[src]

#### `pub fn def_site() -> Span`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_def_site` #54724)

A span that resolves at the macro definition site.

#### `pub fn call_site() -> Span`[src]

The span of the invocation of the current procedural macro. Identifiers created with this span will be resolved as if they were written directly at the macro call location (call-site hygiene) and other code at the macro call site will be able to refer to them as well.

#### `pub fn mixed_site() -> Span`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_mixed_site` #65049)

A span that represents `macro_rules` hygiene, and sometimes resolves at the macro definition site (local variables, labels, `$crate`) and sometimes at the macro call site (everything else). The span location is taken from the call-site.

#### `pub fn source_file(&self) -> SourceFile`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

The original source file into which this span points.

#### `pub fn parent(&self) -> Option<Span>`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

The `Span` for the tokens in the previous macro expansion from which `self` was generated from, if any.

#### `pub fn source(&self) -> Span`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

The span for the origin source code that `self` was generated from. If this `Span` wasn't generated from other macro expansions then the return value is the same as `*self`.

#### `pub fn start(&self) -> LineColumn`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Gets the starting line/column in the source file for this span.

#### `pub fn end(&self) -> LineColumn`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Gets the ending line/column in the source file for this span.

#### `pub fn join(&self, other: Span) -> Option<Span>`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Creates a new span encompassing `self` and `other`.

Returns `None` if `self` and `other` are from different files.

#### `pub fn resolved_at(&self, other: Span) -> Span`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Creates a new span with the same line/column information as `self` but that resolves symbols as though it were at `other`.

#### `pub fn located_at(&self, other: Span) -> Span`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Creates a new span with the same name resolution behavior as `self` but with the line/column information of `other`.

#### `pub fn eq(&self, other: &Span) -> bool`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Compares to spans to see if they're equal.

#### `pub fn source_text(&self) -> Option<String>`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_span` #54725)

Returns the source text behind a span. This preserves the original source code, including spaces and comments. It only returns a result if the span corresponds to real source code.

Note: The observable result of a macro should only rely on the tokens and not on this source text. The result of this function is a best effort to be used for diagnostics only.

#### `pub fn error<T: Into<String>>(self, message: T) -> Diagnostic`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_diagnostic` #54140)

Creates a new `Diagnostic` with the given `message` at the span `self`.

#### `pub fn warning<T: Into<String>>(self, message: T) -> Diagnostic`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_diagnostic` #54140)

Creates a new `Diagnostic` with the given `message` at the span `self`.

#### `pub fn note<T: Into<String>>(self, message: T) -> Diagnostic`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_diagnostic` #54140)

Creates a new `Diagnostic` with the given `message` at the span `self`.

#### `pub fn help<T: Into<String>>(self, message: T) -> Diagnostic`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_diagnostic` #54140)

Creates a new `Diagnostic` with the given `message` at the span `self`.

## Trait Implementations

### `impl MultiSpan for Span`[src]

#### `fn into_spans(self) -> Vec<Span>`[src]

🔬 This is a nightly-only experimental API. (`proc_macro_diagnostic` #54140)

Converts `self` into a `Vec<Span>`.

### `impl !Send for Span`[src]

### `impl !Sync for Span`[src]

### `impl Clone for Span`[src]

#### `fn clone(&self) -> Span`[src]

Returns a copy of the value. Read more

#### `fn clone_from(&mut self, source: &Self)`1.0.0[src]

Performs copy-assignment from `source`. Read more

### `impl Copy for Span`[src]

### `impl Debug for Span`[src]

Prints a span in a form convenient for debugging.

#### `fn fmt(&self, f: &mut Formatter) -> Result`[src]

Formats the value using the given formatter. Read more

## Auto Trait Implementations

### `impl Unpin for Span`

### `impl UnwindSafe for Span`

### `impl RefUnwindSafe for Span`

## Blanket Implementations

### `impl<T> From<T> for T`[src]

#### `fn from(t: T) -> T`[src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `fn into(self) -> U`[src]

Performs the conversion.

### `impl<T> ToOwned for T where
T: Clone,` [src]

#### `type Owned = T`

The resulting type after obtaining ownership.

#### `fn to_owned(&self) -> T`[src]

Creates owned data from borrowed data, usually by cloning. Read more

#### `fn clone_into(&self, target: &mut T)`[src]

🔬 This is a nightly-only experimental API. (`toowned_clone_into` #41263)

recently added

Uses borrowed data to replace owned data, usually by cloning. Read more

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = !`

The type returned in the event of a conversion error.

#### `fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>`[src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

#### `type Error = <U as TryFrom<T>>::Error`

The type returned in the event of a conversion error.

#### `fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>`[src]

Performs the conversion.

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `fn borrow(&self) -> &T`[src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `fn borrow_mut(&mut self) -> &mut T`[src]

Mutably borrows from an owned value. Read more

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `fn type_id(&self) -> TypeId`[src]

Gets the `TypeId` of `self`. Read more