FIX: Length-specified script embedding

resolves: Oldes/Rebol-issues#1941

src/mezz/sys-load.reb

@@ -323,8 +323,9 @@ load: function [
 
  ;-- Try to load the header, handle error:
  not all [
- set [hdr: data:] either object? data [load-ext-module data] [load-header data]
+ set [hdr: data: end:] either object? data [load-ext-module data] [load-header data]
  if word? hdr [cause-error 'syntax hdr source]
+ unless tail? end [data: copy/part data end] 
  ]
  ; data is binary or block now, hdr is object or none
 
@@ -537,7 +538,8 @@ load-module: function [
  ; Get and process the header
  not hdr [
  ; Only happens for string, binary or non-extension file/url source
- set [hdr: code:] load-header/required data
+ set [hdr: code: end:] load-header/required data
+ unless tail? end [code: copy/part code end] 
  case [
  word? hdr [cause-error 'syntax hdr source]
  import none ; /import overrides 'delay option

src/tests/units/load-test.r3

@@ -60,6 +60,14 @@ Rebol [
  --assert block? b: load ["print 'hello" "print 'there"]
  --assert [print 'hello] = b/1
  --assert [print 'there] = b/2
+
+ --test-- "Length-specified script embedding"
+ ;@@ https://github.com/Oldes/Rebol-issues/issues/1941
+ --assert [print "hello"] = load {rebol [length: 14] print "hello" other stuff}
+ --assert 1 = try [do {rebol [length: 2] 1 other stuff}]
+ --assert [lib-local a] = words-of import {rebol [length: 5] a: 1 b: 2 print "evil code"}
+ --assert [lib-local a] = words-of import/check {rebol [length: 5 checksum: #{E9A16FDEC8FF093599E2AA10C30D2D98D1C541C5}] a: 1 b: 2 print "evil code"} #{E9A16FDEC8FF093599E2AA10C30D2D98D1C541C5}
+
  --test-- "issue-858"
  ;@@ https://github.com/Oldes/Rebol-issues/issues/858
  --assert [<] = load mold [ < ]
@@ -78,7 +86,6 @@ Rebol [
 
 ===end-group===
 
-
 ===start-group=== "find-script native"
  --test-- "find-script"
  ;@@ https://github.com/Oldes/Rebol-issues/issues/182