Generated by SassMeister.com.

SassMeister-input.scss

// ----
// Sass (v3.4.12)
// Compass (v1.0.3)
// Breakpoint (v2.5.0)
// ----

@import "breakpoint";

/** Breakpoint settings */

$breakpoints: (
    "medium":       690px,
    "wide":         960px,
    "hidpi":         1.5dppx
);

/**
 * bp: return the requested breakpoint
 * @param  {string} $value The key in the Sass map
 * @return {number}        The value in the Sass map
 *
 * Requires $breakpoints Sass map to be set.
 */
@function bp( $value ) {

	@if not map-has-key( $breakpoints, $value ) {

		@error "ERROR: Requested value '#{$value}' was not found in the breakpoints map.";

	}

	$breakpoint: map-get( $breakpoints, $value );

	@return $breakpoint;
}

.icon {
  background-image: url("../images/icon.png");

  @include breakpoint( bp( "hdpi" ) ) { // Note the misspelling
    background-image: url("../images/icon@2x.png");
  }
}

SassMeister-output.css

ERROR: Requested value 'hdpi' was not found in the breakpoints map.