Bruce/tomo
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Activity

Disallow mutation of read-only views

Browse Source
This commit is contained in:
Bruce Hill 2024-10-27 20:25:16 -04:00
parent 052316261a
commit 63a5032ca0
2 changed files with 15 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
compile.c
View File

@ -278,9 +278,20 @@ CORD compile_type(type_t *t)
static CORD compile_lvalue(env_t *env, ast_t *ast)
{
if (!can_be_mutated(env, ast)) {
if (ast->tag == Index || ast->tag == FieldAccess) {
ast_t *subject = ast->tag == Index ? Match(ast, Index)->indexed : Match(ast, FieldAccess)->fielded;
code_err(subject, "This is an immutable value, you can't assign to it");
if (ast->tag == Index) {
ast_t *subject = Match(ast, Index)->indexed;
type_t *t = get_type(env, subject);
if (t->tag == PointerType && Match(t, PointerType)->is_view)
code_err(ast, "This is a read-only view and you can't mutate its contents");
else
code_err(subject, "This is an immutable value, you can't mutate its contents");
} else if (ast->tag == FieldAccess) {
ast_t *subject = Match(ast, FieldAccess)->fielded;
type_t *t = get_type(env, subject);
if (t->tag == PointerType && Match(t, PointerType)->is_view)
code_err(subject, "This is a read-only view and you can't mutate its fields");
else
code_err(subject, "This is an immutable value, you can't assign to its fields");
} else {
code_err(ast, "This is a value of type %T and can't be used as an assignment target", get_type(env, ast));
}

2
typecheck.c
View File

@ -1293,7 +1293,7 @@ PUREFUNC bool can_be_mutated(env_t *env, ast_t *ast)
auto index = Match(ast, Index);
type_t *indexed_type = get_type(env, index->indexed);
if (indexed_type->tag == PointerType)
return true;
return !Match(indexed_type, PointerType)->is_view;
return can_be_mutated(env, index->indexed);
}
default: return false;