diff options
Diffstat (limited to 'typecheck.c')
| -rw-r--r-- | typecheck.c | 40 |
1 files changed, 30 insertions, 10 deletions
diff --git a/typecheck.c b/typecheck.c index 5f40b078..933f1f90 100644 --- a/typecheck.c +++ b/typecheck.c @@ -1161,18 +1161,38 @@ type_t *get_type(env_t *env, ast_t *ast) case If: { auto if_ = Match(ast, If); - type_t *true_t = get_type(env, if_->body); - if (if_->else_body) { - type_t *false_t = get_type(env, if_->else_body); - type_t *t_either = type_or_type(true_t, false_t); - if (!t_either) - code_err(if_->else_body, - "I was expecting this block to have a %T value (based on earlier clauses), but it actually has a %T value.", - true_t, false_t); - return t_either; - } else { + if (!if_->else_body) return Type(VoidType); + + env_t *truthy_scope = env; + env_t *falsey_scope = env; + if (if_->condition->tag == Declare) { + type_t *condition_type = get_type(env, Match(if_->condition, Declare)->value); + falsey_scope = fresh_scope(env); + bind_statement(falsey_scope, if_->condition); + + truthy_scope = fresh_scope(env); + const char *varname = Match(Match(if_->condition, Declare)->var, Var)->name; + set_binding(truthy_scope, varname, + new(binding_t, .type=Match(condition_type, OptionalType)->type)); + } else if (if_->condition->tag == Var) { + type_t *condition_type = get_type(env, if_->condition); + if (condition_type->tag == OptionalType) { + truthy_scope = fresh_scope(env); + const char *varname = Match(if_->condition, Var)->name; + set_binding(truthy_scope, varname, + new(binding_t, .type=Match(condition_type, OptionalType)->type)); + } } + + type_t *true_t = get_type(truthy_scope, if_->body); + type_t *false_t = get_type(falsey_scope, if_->else_body); + type_t *t_either = type_or_type(true_t, false_t); + if (!t_either) + code_err(if_->else_body, + "I was expecting this block to have a %T value (based on earlier clauses), but it actually has a %T value.", + true_t, false_t); + return t_either; } case When: { |