FIX: Length-specified script embedding

resolves: Oldes/Rebol-issues#1941

Author: Oldes

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