diff --git a/500fake-screen.mu b/500fake-screen.mu
index a78d7868..a2e9ae40 100644
--- a/500fake-screen.mu
+++ b/500fake-screen.mu
@@ -110,10 +110,10 @@ fn draw-grapheme _screen: (addr screen), g: grapheme, x: int, y: int, color: int
     return
   }
   # fake screen
-  var idx/ecx: int <- screen-cell-index screen, x, y
+  var index/ecx: int <- screen-cell-index screen, x, y
   var data-ah/eax: (addr handle array screen-cell) <- get screen, data
   var data/eax: (addr array screen-cell) <- lookup *data-ah
-  var offset/ecx: (offset screen-cell) <- compute-offset data, idx
+  var offset/ecx: (offset screen-cell) <- compute-offset data, index
   var dest-cell/ecx: (addr screen-cell) <- index data, offset
   var dest-grapheme/eax: (addr grapheme) <- get dest-cell, data
   var g2/edx: grapheme <- copy g
@@ -333,8 +333,8 @@ fn fake-screen-empty? _screen: (addr screen) -> _/eax: boolean {
     {
       compare x, width
       break-if->=
-      var idx/ecx: int <- pixel-index screen, x, y
-      var color-addr/ecx: (addr byte) <- index pixels, idx
+      var index/ecx: int <- pixel-index screen, x, y
+      var color-addr/ecx: (addr byte) <- index pixels, index
       var color/ecx: byte <- copy-byte *color-addr
       compare color, 0
       {
@@ -426,17 +426,17 @@ fn clear-rect-on-real-screen xmin: int, ymin: int, xmax: int, ymax: int, backgro
 
 fn screen-grapheme-at _screen: (addr screen), x: int, y: int -> _/eax: grapheme {
   var screen/esi: (addr screen) <- copy _screen
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  var result/eax: grapheme <- screen-grapheme-at-idx screen, idx
+  var index/ecx: int <- screen-cell-index screen, x, y
+  var result/eax: grapheme <- screen-grapheme-at-index screen, index
   return result
 }
 
-fn screen-grapheme-at-idx _screen: (addr screen), idx-on-stack: int -> _/eax: grapheme {
+fn screen-grapheme-at-index _screen: (addr screen), _index: int -> _/eax: grapheme {
   var screen/esi: (addr screen) <- copy _screen
   var data-ah/eax: (addr handle array screen-cell) <- get screen, data
   var data/eax: (addr array screen-cell) <- lookup *data-ah
-  var idx/ecx: int <- copy idx-on-stack
-  var offset/ecx: (offset screen-cell) <- compute-offset data, idx
+  var index/ecx: int <- copy _index
+  var offset/ecx: (offset screen-cell) <- compute-offset data, index
   var cell/eax: (addr screen-cell) <- index data, offset
   var src/eax: (addr grapheme) <- get cell, data
   return *src
@@ -444,17 +444,17 @@ fn screen-grapheme-at-idx _screen: (addr screen), idx-on-stack: int -> _/eax: gr
 
 fn screen-color-at _screen: (addr screen), x: int, y: int -> _/eax: int {
   var screen/esi: (addr screen) <- copy _screen
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  var result/eax: int <- screen-color-at-idx screen, idx
+  var index/ecx: int <- screen-cell-index screen, x, y
+  var result/eax: int <- screen-color-at-index screen, index
   return result
 }
 
-fn screen-color-at-idx _screen: (addr screen), idx-on-stack: int -> _/eax: int {
+fn screen-color-at-index _screen: (addr screen), _index: int -> _/eax: int {
   var screen/esi: (addr screen) <- copy _screen
   var data-ah/eax: (addr handle array screen-cell) <- get screen, data
   var data/eax: (addr array screen-cell) <- lookup *data-ah
-  var idx/ecx: int <- copy idx-on-stack
-  var offset/ecx: (offset screen-cell) <- compute-offset data, idx
+  var index/ecx: int <- copy _index
+  var offset/ecx: (offset screen-cell) <- compute-offset data, index
   var cell/eax: (addr screen-cell) <- index data, offset
   var src/eax: (addr int) <- get cell, color
   var result/eax: int <- copy *src
@@ -463,17 +463,17 @@ fn screen-color-at-idx _screen: (addr screen), idx-on-stack: int -> _/eax: int {
 
 fn screen-background-color-at _screen: (addr screen), x: int, y: int -> _/eax: int {
   var screen/esi: (addr screen) <- copy _screen
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  var result/eax: int <- screen-background-color-at-idx screen, idx
+  var index/ecx: int <- screen-cell-index screen, x, y
+  var result/eax: int <- screen-background-color-at-index screen, index
   return result
 }
 
-fn screen-background-color-at-idx _screen: (addr screen), idx-on-stack: int -> _/eax: int {
+fn screen-background-color-at-index _screen: (addr screen), _index: int -> _/eax: int {
   var screen/esi: (addr screen) <- copy _screen
   var data-ah/eax: (addr handle array screen-cell) <- get screen, data
   var data/eax: (addr array screen-cell) <- lookup *data-ah
-  var idx/ecx: int <- copy idx-on-stack
-  var offset/ecx: (offset screen-cell) <- compute-offset data, idx
+  var index/ecx: int <- copy _index
+  var offset/ecx: (offset screen-cell) <- compute-offset data, index
   var cell/eax: (addr screen-cell) <- index data, offset
   var src/eax: (addr int) <- get cell, background-color
   var result/eax: int <- copy *src
@@ -496,8 +496,8 @@ fn pixel screen: (addr screen), x: int, y: int, color: int {
     break-if-!=
     abort "pixel graphics not enabled for this screen"
   }
-  var idx/ecx: int <- pixel-index screen, x, y
-  var dest/ecx: (addr byte) <- index pixels, idx
+  var index/ecx: int <- pixel-index screen, x, y
+  var dest/ecx: (addr byte) <- index pixels, index
   var src/eax: byte <- copy-byte color
   copy-byte-to *dest, src
 }
diff --git a/504test-screen.mu b/504test-screen.mu
index 7c5a653b..65c72a83 100644
--- a/504test-screen.mu
+++ b/504test-screen.mu
@@ -8,11 +8,11 @@ fn check-screen-row screen: (addr screen), y: int, expected: (addr array byte),
   check-screen-row-from screen, 0/x, y, expected, msg
 }
 
-fn check-screen-row-from screen-on-stack: (addr screen), x: int, y: int, expected: (addr array byte), msg: (addr array byte) {
-  var screen/esi: (addr screen) <- copy screen-on-stack
+fn check-screen-row-from _screen: (addr screen), x: int, y: int, expected: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy _screen
   var failure-count/edi: int <- copy 0
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  # compare 'expected' with the screen contents starting at 'idx', grapheme by grapheme
+  var index/ecx: int <- screen-cell-index screen, x, y
+  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
   var e: (stream byte 0x100)
   var e-addr/edx: (addr stream byte) <- address e
   write e-addr, expected
@@ -20,7 +20,7 @@ fn check-screen-row-from screen-on-stack: (addr screen), x: int, y: int, expecte
     var done?/eax: boolean <- stream-empty? e-addr
     compare done?, 0
     break-if-!=
-    var _g/eax: grapheme <- screen-grapheme-at-idx screen, idx
+    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
     var g/ebx: grapheme <- copy _g
     var expected-grapheme/eax: grapheme <- read-grapheme e-addr
     # compare graphemes
@@ -51,7 +51,7 @@ fn check-screen-row-from screen-on-stack: (addr screen), x: int, y: int, expecte
       draw-text-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, "'", 3/fg/cyan, 0/bg
       move-cursor-to-left-margin-of-next-line 0/screen
     }
-    idx <- increment
+    index <- increment
     increment x
     loop
   }
@@ -72,10 +72,10 @@ fn check-screen-row-in-color screen: (addr screen), fg: int, y: int, expected: (
   check-screen-row-in-color-from screen, fg, y, 0/x, expected, msg
 }
 
-fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
-  var screen/esi: (addr screen) <- copy screen-on-stack
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  # compare 'expected' with the screen contents starting at 'idx', grapheme by grapheme
+fn check-screen-row-in-color-from _screen: (addr screen), fg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy _screen
+  var index/ecx: int <- screen-cell-index screen, x, y
+  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
   var e: (stream byte 0x100)
   var e-addr/edx: (addr stream byte) <- address e
   write e-addr, expected
@@ -83,7 +83,7 @@ fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: in
     var done?/eax: boolean <- stream-empty? e-addr
     compare done?, 0
     break-if-!=
-    var _g/eax: grapheme <- screen-grapheme-at-idx screen, idx
+    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
     var g/ebx: grapheme <- copy _g
     var _expected-grapheme/eax: grapheme <- read-grapheme e-addr
     var expected-grapheme/edi: grapheme <- copy _expected-grapheme
@@ -99,7 +99,7 @@ fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: in
       {
         compare expected-grapheme, 0x20
         break-if-!=
-        var color/eax: int <- screen-color-at-idx screen, idx
+        var color/eax: int <- screen-color-at-index screen, index
         compare color, fg
         break-if-!= $check-screen-row-in-color-from:compare-cells
       }
@@ -129,7 +129,7 @@ fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: in
         move-cursor-to-left-margin-of-next-line 0/screen
       }
       $check-screen-row-in-color-from:compare-colors: {
-        var color/eax: int <- screen-color-at-idx screen, idx
+        var color/eax: int <- screen-color-at-index screen, index
         compare fg, color
         {
           break-if-!=
@@ -153,7 +153,7 @@ fn check-screen-row-in-color-from screen-on-stack: (addr screen), fg: int, y: in
         move-cursor-to-left-margin-of-next-line 0/screen
       }
     }
-    idx <- increment
+    index <- increment
     increment x
     loop
   }
@@ -163,10 +163,10 @@ fn check-screen-row-in-background-color screen: (addr screen), bg: int, y: int,
   check-screen-row-in-background-color-from screen, bg, y, 0/x, expected, msg
 }
 
-fn check-screen-row-in-background-color-from screen-on-stack: (addr screen), bg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
-  var screen/esi: (addr screen) <- copy screen-on-stack
-  var idx/ecx: int <- screen-cell-index screen, x, y
-  # compare 'expected' with the screen contents starting at 'idx', grapheme by grapheme
+fn check-screen-row-in-background-color-from _screen: (addr screen), bg: int, y: int, x: int, expected: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy _screen
+  var index/ecx: int <- screen-cell-index screen, x, y
+  # compare 'expected' with the screen contents starting at 'index', grapheme by grapheme
   var e: (stream byte 0x100)
   var e-addr/edx: (addr stream byte) <- address e
   write e-addr, expected
@@ -174,7 +174,7 @@ fn check-screen-row-in-background-color-from screen-on-stack: (addr screen), bg:
     var done?/eax: boolean <- stream-empty? e-addr
     compare done?, 0
     break-if-!=
-    var _g/eax: grapheme <- screen-grapheme-at-idx screen, idx
+    var _g/eax: grapheme <- screen-grapheme-at-index screen, index
     var g/ebx: grapheme <- copy _g
     var _expected-grapheme/eax: grapheme <- read-grapheme e-addr
     var expected-grapheme/edi: grapheme <- copy _expected-grapheme
@@ -190,7 +190,7 @@ fn check-screen-row-in-background-color-from screen-on-stack: (addr screen), bg:
       {
         compare expected-grapheme, 0x20
         break-if-!=
-        var background-color/eax: int <- screen-background-color-at-idx screen, idx
+        var background-color/eax: int <- screen-background-color-at-index screen, index
         compare background-color, bg
         break-if-!= $check-screen-row-in-background-color-from:compare-cells
       }
@@ -221,7 +221,7 @@ fn check-screen-row-in-background-color-from screen-on-stack: (addr screen), bg:
         break $check-screen-row-in-background-color-from:compare-graphemes
       }
       $check-screen-row-in-background-color-from:compare-background-colors: {
-        var background-color/eax: int <- screen-background-color-at-idx screen, idx
+        var background-color/eax: int <- screen-background-color-at-index screen, index
         compare bg, background-color
         {
           break-if-!=
@@ -245,7 +245,7 @@ fn check-screen-row-in-background-color-from screen-on-stack: (addr screen), bg:
         move-cursor-to-left-margin-of-next-line 0/screen
       }
     }
-    idx <- increment
+    index <- increment
     increment x
     loop
   }
@@ -258,10 +258,10 @@ fn check-background-color-in-screen-row screen: (addr screen), bg: int, y: int,
   check-background-color-in-screen-row-from screen, bg, y, 0/x, expected-bitmap, msg
 }
 
-fn check-background-color-in-screen-row-from screen-on-stack: (addr screen), bg: int, y: int, x: int, expected-bitmap: (addr array byte), msg: (addr array byte) {
-  var screen/esi: (addr screen) <- copy screen-on-stack
+fn check-background-color-in-screen-row-from _screen: (addr screen), bg: int, y: int, x: int, expected-bitmap: (addr array byte), msg: (addr array byte) {
+  var screen/esi: (addr screen) <- copy _screen
   var failure-count: int
-  var idx/ecx: int <- screen-cell-index screen, x, y
+  var index/ecx: int <- screen-cell-index screen, x, y
   # compare background color where 'expected-bitmap' is a non-space
   var e: (stream byte 0x100)
   var e-addr/edx: (addr stream byte) <- address e
@@ -273,7 +273,7 @@ fn check-background-color-in-screen-row-from screen-on-stack: (addr screen), bg:
     var _expected-bit/eax: grapheme <- read-grapheme e-addr
     var expected-bit/edi: grapheme <- copy _expected-bit
     $check-background-color-in-screen-row-from:compare-cells: {
-      var background-color/eax: int <- screen-background-color-at-idx screen, idx
+      var background-color/eax: int <- screen-background-color-at-index screen, index
       # if expected-bit is space, assert that background is NOT bg
       compare expected-bit, 0x20
       {
@@ -306,7 +306,7 @@ fn check-background-color-in-screen-row-from screen-on-stack: (addr screen), bg:
       draw-int32-hex-wrapping-right-then-down-from-cursor-over-full-screen 0/screen, background-color, 3/fg/cyan, 0/bg
       move-cursor-to-left-margin-of-next-line 0/screen
     }
-    idx <- increment
+    index <- increment
     increment x
     loop
   }
@@ -322,8 +322,8 @@ fn check-background-color-in-screen-row-from screen-on-stack: (addr screen), bg:
 }
 
 fn test-draw-single-grapheme {
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var _screen: screen
+  var screen/esi: (addr screen) <- address _screen
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   draw-code-point screen, 0x61/a, 0/x, 0/y, 1/fg, 2/bg
   check-screen-row screen, 0/y, "a", "F - test-draw-single-grapheme"  # top-left corner of the screen
@@ -333,8 +333,8 @@ fn test-draw-single-grapheme {
 }
 
 fn test-draw-multiple-graphemes {
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var _screen: screen
+  var screen/esi: (addr screen) <- address _screen
   initialize-screen screen, 0x10/rows, 4/cols, 0/no-pixel-graphics
   draw-text-wrapping-right-then-down-from-cursor-over-full-screen screen, "Hello, 世界", 1/fg, 2/bg
   check-screen-row screen, 0/y, "Hello, 世界", "F - test-draw-multiple-graphemes"
diff --git a/513grapheme-stack.mu b/513grapheme-stack.mu
index 13f0e31c..2db873a0 100644
--- a/513grapheme-stack.mu
+++ b/513grapheme-stack.mu
@@ -205,8 +205,8 @@ fn test-render-grapheme-stack {
   g <- copy 0x63/c
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-bottom screen, gs, 0/x, 0/y, 0/no-highlight-matching-open-paren, 0/open-paren-depth
@@ -237,8 +237,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-close-paren {
   g <- copy 0x28/open-paren
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-top screen, gs, 0/x, 2/y, 1/cursor=true
@@ -271,8 +271,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-close-paren-2 {
   g <- copy 0x28/open-paren
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-top screen, gs, 0/x, 2/y, 1/cursor=true
@@ -293,8 +293,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-open-paren-with-close-
   g <- copy 0x29/close-paren
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-bottom screen, gs, 0/x, 2/y, 1/highlight-matching-open-paren, 1/open-paren-depth
@@ -320,8 +320,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-open-paren-with-close-
   g <- copy 0x29/close-paren
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-bottom screen, gs, 0/x, 2/y, 1/highlight-matching-open-paren, 1/open-paren-depth
@@ -339,8 +339,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-open-paren {
   g <- copy 0x62/b
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-bottom screen, gs, 0/x, 2/y, 1/highlight-matching-open-paren, 0/open-paren-depth
@@ -364,8 +364,8 @@ fn test-render-grapheme-stack-while-highlighting-matching-open-paren-2 {
   g <- copy 0x29/close-paren
   push-grapheme-stack gs, g
   # setup: screen
-  var screen-on-stack: screen
-  var screen/esi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/esi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-stack-from-bottom screen, gs, 0/x, 2/y, 1/highlight-matching-open-paren, 0/open-paren-depth
diff --git a/514gap-buffer.mu b/514gap-buffer.mu
index 0077d6fd..39745d1f 100644
--- a/514gap-buffer.mu
+++ b/514gap-buffer.mu
@@ -818,8 +818,8 @@ fn test-render-gap-buffer-without-cursor {
   var gap/esi: (addr gap-buffer) <- address gap-storage
   initialize-gap-buffer-with gap, "abc"
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 0/no-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -836,8 +836,8 @@ fn test-render-gap-buffer-with-cursor-at-end {
   initialize-gap-buffer-with gap, "abc"
   gap-to-end gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -856,8 +856,8 @@ fn test-render-gap-buffer-with-cursor-in-middle {
   gap-to-end gap
   var dummy/eax: grapheme <- gap-left gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -873,8 +873,8 @@ fn test-render-gap-buffer-with-cursor-at-start {
   initialize-gap-buffer-with gap, "abc"
   gap-to-start gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -890,8 +890,8 @@ fn test-render-gap-buffer-highlight-matching-close-paren {
   initialize-gap-buffer-with gap, "(a)"
   gap-to-start gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -908,8 +908,8 @@ fn test-render-gap-buffer-highlight-matching-open-paren {
   gap-to-end gap
   var dummy/eax: grapheme <- gap-left gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg
@@ -925,8 +925,8 @@ fn test-render-gap-buffer-highlight-matching-open-paren-of-end {
   initialize-gap-buffer-with gap, "(a)"
   gap-to-end gap
   # setup: screen
-  var screen-on-stack: screen
-  var screen/edi: (addr screen) <- address screen-on-stack
+  var screen-storage: screen
+  var screen/edi: (addr screen) <- address screen-storage
   initialize-screen screen, 5, 4, 0/no-pixel-graphics
   #
   var x/eax: int <- render-gap-buffer screen, gap, 0/x, 0/y, 1/show-cursor, 3/fg, 0xc5/bg=blue-bg