# Function std::intrinsics::assume[−][src]

    pub unsafe extern "rust-intrinsic" fn assume(b: bool)

🔬 This is a nightly-only experimental API. (`core_intrinsics`)

intrinsics are unlikely to ever be stabilized, instead they should be used through stabilized interfaces in the rest of the standard library

Informs the optimizer that a condition is always true. If the condition is false, the behavior is undefined.

No code is generated for this intrinsic, but the optimizer will try to preserve it (and its condition) between passes, which may interfere with optimization of surrounding code and reduce performance. It should not be used if the invariant can be discovered by the optimizer on its own, or if it does not enable any significant optimizations.

# 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`)