fix(analyzer): propagate redefined variable types through break statements in loops

Signed-off-by: azjezz <[email protected]>

Author: azjezz

crates/analyzer/src/statement/loop/break.rs

@@ -87,6 +87,22 @@ impl<'ast, 'arena> Analyzable<'ast, 'arena> for Break<'arena> {
             let redefined_vars =
                 block_context.get_redefined_locals(&loop_scope.parent_context_variables, false, &mut removed_var_ids);
 
+            for (var_id, parent_type) in &loop_scope.parent_context_variables {
+                if !redefined_vars.contains_key(var_id) {
+                    loop_scope.possibly_redefined_loop_parent_variables.insert(
+                        *var_id,
+                        Rc::new(add_optional_union_type(
+                            (**parent_type).clone(),
+                            loop_scope
+                                .possibly_redefined_loop_parent_variables
+                                .get(var_id)
+                                .map(std::convert::AsRef::as_ref),
+                            context.codebase,
+                        )),
+                    );
+                }
+            }
+
             for (var_id, var_type) in redefined_vars {
                 loop_scope.possibly_redefined_loop_parent_variables.insert(
                     var_id,

crates/analyzer/src/statement/loop/mod.rs

@@ -734,6 +734,13 @@ fn analyze<'ctx, 'ast, 'arena>(
                         *variable_id,
                         Rc::new(combine_union_types(variable_type, possibly_defined_type, codebase, true)),
                     );
+                } else if let Some(possibly_redefined_type) =
+                    loop_scope.possibly_redefined_loop_parent_variables.get(variable_id)
+                {
+                    loop_parent_context.locals.insert(
+                        *variable_id,
+                        Rc::new(combine_union_types(variable_type, possibly_redefined_type, codebase, true)),
+                    );
                 }
             } else {
                 loop_parent_context.locals.insert(*variable_id, variable_type.clone());

crates/analyzer/tests/cases/break_narrowing.php

@@ -0,0 +1,21 @@
+<?php
+
+function takeString(string $s): void
+{
+    takeString($s);
+}
+
+function testSimpleBreakNarrowing(null|string $value): string
+{
+    while (true) {
+        if ($value === null) {
+            $value = 'default';
+            break;
+        }
+        break;
+    }
+
+    takeString($value);
+
+    return $value;
+}

crates/analyzer/tests/mod.rs

@@ -38,6 +38,7 @@ test_case!(array_shape_fields);
 test_case!(assert_concrete_to_template_type);
 test_case!(assert_generic_array_key_is_array_key);
 test_case!(bare_identifier_in_array_access);
+test_case!(break_narrowing);
 test_case!(by_reference_invalidation);
 test_case!(class_like_constant_access);
 test_case!(collection_types);