Handle l-value refs correctly

Reviewed By: jvillard

Differential Revision: D3757766

fbshipit-source-id: 12edcfc

infer/src/clang/ComponentKit.ml

@@ -77,11 +77,16 @@ let mutable_local_vars_advice context decl =
   let open CFrontend_utils.Ast_utils in
   match decl with
   | Clang_ast_t.VarDecl(decl_info, _, qual_type, _) ->
+      let is_const_ref = match Ast_utils.get_type qual_type.qt_type_ptr with
+        | Some LValueReferenceType (_, {Clang_ast_t.qt_is_const}) ->
+            qt_is_const
+        | _ -> false in
+      let is_const = qual_type.qt_is_const || is_const_ref in
       let condition = context.CLintersContext.is_ck_translation_unit
                       && is_in_main_file decl
                       && (is_objc () || is_objcpp ())
                       && (not (is_syntactically_global_var decl))
-                      && (not qual_type.qt_is_const) in
+                      && (not is_const) in
       if condition then
         Some {
           CIssue.issue = CIssue.Mutable_local_variable_in_component_file;

infer/tests/codetoanalyze/objcpp/componentkit/Test.mm

@@ -92,3 +92,17 @@ typedef struct { int thisStructIsEmpty; } CKSize;
                                      size:{}]];
 }
 @end
+
+typedef struct { int a; } BarStruct;
+
+@interface BarComponent : CKCompositeComponent
+@end
+@implementation BarComponent
++ (instancetype) new {
+  // C++ structs
+  BarStruct s1; // error
+  const BarStruct& s2 = s1; // no error
+  BarStruct& s3 = s1; // error
+  const BarStruct s4 = {.a = 3}; // no error
+}
+@end

infer/tests/endtoend/objcpp/componentkit/MutableLocalVariableTest.java

@@ -10,7 +10,7 @@
 package endtoend.objcpp.componentkit;
 
 import static org.hamcrest.MatcherAssert.assertThat;
-import static utils.matchers.ResultContainsLineNumbers.containsLines;
+import static utils.matchers.ResultContainsLineNumbers.containsOnlyLines;
 import static utils.matchers.ResultContainsErrorInMethod.contains;
 
 import com.google.common.collect.ImmutableList;
@@ -51,7 +51,7 @@ public class MutableLocalVariableTest {
     assertThat(
         "Results should contain " + MUTABLE_LOCAL_VARIABLE_IN_COMPONENT_FILE,
         inferResults,
-        containsLines(new int[]{58, 69, 74, 76, 80, 85}));
+        containsOnlyLines(new int[]{58, 69, 74, 76, 80, 85, 103, 105}));
   }
 
   @Test