fix and update

self_hosted/main.jou

@@ -90,10 +90,11 @@ def parse_args(argc: int, argv: byte**) -> CommandLineArgs:
 
     return result
 
-def find_file(files: FileState*, nfiles: int, path: byte*) -> FileState:
+def find_file(files: FileState*, nfiles: int, path: byte*) -> FileState*:
     for i = 0; i < nfiles; i++:
         if strcmp(files[i].ast.path, path) == 0:
-            return files[i]
+            return &files[i]
+    return NULL
 
 # C:\Users\myname\.foo-bar.jou --> "_foo_bar"
 # Result never contains "-", so you can add "-" separated suffixes without conflicts.
@@ -125,7 +126,7 @@ def get_sane_filename(path: byte*) -> byte[50]:
 def check_main_function(ast: AstFile*) -> bool:
     for i = 0; i < ast->body.nstatements; i++:
         s = &ast->body.statements[i]
-        if (s->kind == AstStatementKind::Function and strcmp(s->function.signature.name, "main") == 0):
+        if s->kind == AstStatementKind::Function and strcmp(s->function.signature.name, "main") == 0:
             return True
     return False
 
@@ -222,7 +223,7 @@ class Compiler:
 
             evaluate_compile_time_if_statements_in_body(&ast.body)
 
-            if (strcmp(item.path, self->args->main_path) == 0 and check_main_function(&self->files->ast)):
+            if item.is_imported and check_main_function(&ast):
                 assert item.import_location.path != NULL
                 fail(item.import_location, "imported file should not have `main` function")
 
@@ -484,10 +485,10 @@ def main(argc: int, argv: byte**) -> int:
         compiler.typecheck_stage3_all_files()
 
         mainfile = find_file(compiler.files, compiler.nfiles, args.main_path)
-        assert mainfile
+        assert mainfile != NULL
 
-        if (not check_main_function(&mainfile.ast)):
-            l = Location{path=mainfile->path, lineno=0}
+        if not check_main_function(&mainfile->ast):
+            l = Location{path=mainfile->ast.path, lineno=0}
             fail(l, "missing `main` function to execute the program")
 
         object_files = compiler.create_object_files()