syntax: while/loop exit type evolution

[nit.git] / src / syntax / typing.nit

diff --git a/src/syntax/typing.nit b/src/syntax/typing.nit
index 7f625e8..84a8483 100644 (file)
--- a/src/syntax/typing.nit
+++ b/src/syntax/typing.nit
@@ -442,10 +442,13 @@ end
 redef class ABreakExpr
        redef fun after_typing(v)
        do
+               var unreash = v.variable_ctx.unreash
                v.variable_ctx.unreash = true
                var esc = compute_escapable_block(v.escapable_ctx)
                if esc == null then return
 
+               if not unreash then esc.break_variable_contexts.add(v.variable_ctx)
+
                var bl = esc.break_list
                if n_expr == null and bl != null then
                        v.error(self, "Error: break with a value required in this block.")
@@ -552,6 +555,12 @@ redef class AWhileExpr
                end
 
                v.variable_ctx = old_var_ctx
+
+               # Compute outside context (assert !cond + all breaks)
+               v.use_if_false_variable_ctx(n_expr)
+               escapable.break_variable_contexts.add(v.variable_ctx)
+               old_var_ctx.combine_merge(escapable.break_variable_contexts, v.base_variable_ctx)
+
                v.base_variable_ctx = old_base_var_ctx
                v.escapable_ctx.pop
                _is_typed = true
@@ -578,6 +587,11 @@ redef class ALoopExpr
                        v.enter_visit(n_block)
                end
 
+               # Compute outside context (assert all breaks)
+               if not escapable.break_variable_contexts.is_empty then
+                       old_var_ctx.combine_merge(escapable.break_variable_contexts, v.base_variable_ctx)
+               end
+
                v.variable_ctx = old_var_ctx
                v.base_variable_ctx = old_base_var_ctx
                v.escapable_ctx.pop