diff --git a/src/librustc_mir/hair/pattern/_match.rs b/src/librustc_mir/hair/pattern/_match.rs index cf8ef8c76998..6d33c23dfdeb 100644 --- a/src/librustc_mir/hair/pattern/_match.rs +++ b/src/librustc_mir/hair/pattern/_match.rs @@ -1625,36 +1625,6 @@ fn split_grouped_constructors<'p, 'tcx>( split_ctors } -/// Checks whether there exists any shared value in either `ctor` or `pat` by intersecting them. -fn constructor_intersects_pattern<'p, 'tcx>( - tcx: TyCtxt<'tcx>, - param_env: ty::ParamEnv<'tcx>, - ctor: &Constructor<'tcx>, - pat: &'p Pat<'tcx>, -) -> Option; 2]>> { - if should_treat_range_exhaustively(tcx, ctor) { - match (IntRange::from_ctor(tcx, param_env, ctor), IntRange::from_pat(tcx, param_env, pat)) { - (Some(ctor), Some(pat)) => { - ctor.intersection(&pat).map(|_| { - let (pat_lo, pat_hi) = pat.range.into_inner(); - let (ctor_lo, ctor_hi) = ctor.range.into_inner(); - assert!(pat_lo <= ctor_lo && ctor_hi <= pat_hi); - smallvec![] - }) - } - _ => None, - } - } else { - // Fallback for non-ranges and ranges that involve floating-point numbers, which are not - // conveniently handled by `IntRange`. For these cases, the constructor may not be a range - // so intersection actually devolves into being covered by the pattern. - match constructor_covered_by_range(tcx, param_env, ctor, pat) { - Ok(true) => Some(smallvec![]), - Ok(false) | Err(ErrorReported) => None, - } - } -} - fn constructor_covered_by_range<'tcx>( tcx: TyCtxt<'tcx>, param_env: ty::ParamEnv<'tcx>, @@ -1845,9 +1815,32 @@ fn specialize<'p, 'a: 'p, 'tcx>( PatKind::Constant { .. } | PatKind::Range { .. } => { // If the constructor is a: - // Single value: add a row if the pattern contains the constructor. - // Range: add a row if the constructor intersects the pattern. - constructor_intersects_pattern(cx.tcx, cx.param_env, constructor, pat) + // - Single value: add a row if the pattern contains the constructor. + // - Range: add a row if the constructor intersects the pattern. + if should_treat_range_exhaustively(cx.tcx, constructor) { + match (IntRange::from_ctor(cx.tcx, cx.param_env, constructor), + IntRange::from_pat(cx.tcx, cx.param_env, pat)) { + (Some(ctor), Some(pat)) => { + ctor.intersection(&pat).map(|_| { + let (pat_lo, pat_hi) = pat.range.into_inner(); + let (ctor_lo, ctor_hi) = ctor.range.into_inner(); + assert!(pat_lo <= ctor_lo && ctor_hi <= pat_hi); + smallvec![] + }) + } + _ => None, + } + } else { + // Fallback for non-ranges and ranges that involve + // floating-point numbers, which are not conveniently handled + // by `IntRange`. For these cases, the constructor may not be a + // range so intersection actually devolves into being covered + // by the pattern. + match constructor_covered_by_range(cx.tcx, cx.param_env, constructor, pat) { + Ok(true) => Some(smallvec![]), + Ok(false) | Err(ErrorReported) => None, + } + } } PatKind::Array { ref prefix, ref slice, ref suffix } |