Support #! as a comment on the first line only.

releasenotes.md

@@ -12,6 +12,7 @@
 - Comparing slices and arrays of user-defined types that implement == operator now works #2486.
 - Add 'loop-vectorize', 'slp-vectorize', 'unroll-loops' and 'merge-functions' optimization flags #2491. 
 - Add exec timings to -vv output #2490.
+- Support #! as a comment on the first line only.
 
 ### Fixes
 - Compiler assert with var x @noinit = 0 #2452

src/compiler/lexer.c

@@ -278,6 +278,14 @@ static void skip_whitespace(Lexer *lexer)
 			case '\r':
 				// Already filtered out.
 				UNREACHABLE_VOID
+			case '#':
+				if (lexer->file_begin == lexer->current && peek_next(lexer) == '!')
+				{
+					skip(lexer, 2);
+					parse_line_comment(lexer);
+					continue;
+				}
+				return;
 			default:
 				return;
 		}