I'm not sure whether this is a compiler or language docs issue, so I'll report it here and cc @rust-lang/lang-docs

The Reference and FLS specify that the operands of extending array expressions are extending. Clicking through to see the definition of array expressions, both specifications include [expr; N] repetition expressions. Thus from these specifications I would expect

let x = [&temp(); 1];

to extend temp() to live in the same scope as x. This is not the case (playground):

fn temp() {} fn main() { let extended = [&temp()]; extended; // this is okay let not_extended = [&temp(); 1]; not_extended; //~^ ERROR: temporary value dropped while borrowed }

On the compiler side, the implementation of extending expressions only includes normal array expressions, not repetition expressions, which are represented as hir::ExprKind::Repeat rather than hir:ExprKind::Array.

@rustbot label +T-compiler +T-lang +T-lang-docs +A-docs +A-temporary-lifetime-extension +A-array