[PATCH] D59754: [Sema] Add c++2a designated initializer warnings

[Nicolas Lesser via Phabricator via cfe-commits]

Rakete1111 added inline comments.


================
Comment at: clang/lib/Sema/SemaInit.cpp:2017
 
+      auto LastIdx = Field != FieldEnd
+                         ? Field->getFieldIndex()
----------------
Can `Field` ever be `FieldEnd` at this point?


================
Comment at: clang/lib/Sema/SemaInit.cpp:2044
+                         : std::distance(RD->field_begin(), RD->field_end());
+      if (VerifyOnly && (LastIdx >= NextIdx || HasNonDesignatedInit) &&
+          SemaRef.getLangOpts().CPlusPlus2a)
----------------
`!VerifyOnly` and braces please.


================
Comment at: clang/lib/Sema/SemaInit.cpp:2065
+    // Warn on mixed designators in C++20
+    if (VerifyOnly && HasDesignatedInit && SemaRef.getLangOpts().CPlusPlus2a)
+      SemaRef.Diag(Init->getBeginLoc(), diag::ext_designated_init)
----------------
Same here. It should be `!VerifyOnly`. Also braces for the if statement.


================
Comment at: clang/lib/Sema/SemaInit.cpp:3087
   if (!getLangOpts().C99)
-    Diag(DIE->getBeginLoc(), diag::ext_designated_init)
-        << DIE->getSourceRange();
+    // Warn on nested and array designators in C++20
+    if (!getLangOpts().CPlusPlus2a || Desig.getNumDesignators() > 1 ||
----------------
Missing dot.


================
Comment at: clang/lib/Sema/SemaInit.cpp:3089
+    if (!getLangOpts().CPlusPlus2a || Desig.getNumDesignators() > 1 ||
+        HasArrayDesignator)
+      Diag(DIE->getBeginLoc(), diag::ext_designated_init)
----------------
Braces.


================
Comment at: clang/test/SemaCXX/cxx2a-initializer-aggregates.cpp:30
+// out of order designators
+A a1 = {.y = 1, .x = 2}; // expected-warning {{designated initializers are a C99 feature}}
+
----------------
Those warnings are misleading, since C++20 does have designated initializers; they just don't support some stuff that C99 does. It would be better  IMO if you could separate them. As in, the above should give you: `out-of-order designated initializers are a C99 feature` or something like that.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D59754/new/

https://reviews.llvm.org/D59754