PR31742: Don't emit a bogus "zero size array" extwarn when initializing a

runtime-sized array from an empty list in an array new.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@292991 91177308-0d34-0410-b5e6-96231b3b80d8

Author: zygoloid

Diff for: lib/Sema/SemaInit.cpp

@@ -1684,7 +1684,7 @@ void InitListChecker::CheckArrayType(const InitializedEntity &Entity,
     // If this is an incomplete array type, the actual type needs to
     // be calculated here.
     llvm::APSInt Zero(maxElements.getBitWidth(), maxElements.isUnsigned());
-    if (maxElements == Zero) {
+    if (maxElements == Zero && !Entity.isVariableLengthArrayNew()) {
       // Sizing an array implicitly to zero is not allowed by ISO C,
       // but is supported by GNU.
       SemaRef.Diag(IList->getLocStart(),

Diff for: test/SemaCXX/new-delete-cxx0x.cpp

@@ -1,4 +1,4 @@
-// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 -triple=i686-pc-linux-gnu
+// RUN: %clang_cc1 -fsyntax-only -verify %s -std=c++11 -triple=i686-pc-linux-gnu -pedantic
 
 void ugly_news(int *ip) {
   (void)new int[-1]; // expected-error {{array size is negative}}
@@ -29,6 +29,7 @@ void fn(int n) {
   (void) new int[2] {1, 2};
   (void) new S[2] {1, 2};
   (void) new S[3] {1, 2};
+  (void) new S[n] {};
   // C++11 [expr.new]p19:
   //   If the new-expression creates an object or an array of objects of class
   //   type, access and ambiguity control are done for the allocation function,
@@ -44,6 +45,7 @@ void fn(int n) {
   (void) new T[2] {1, 2}; // ok
   (void) new T[3] {1, 2}; // expected-error {{no matching constructor}} expected-note {{in implicit initialization of array element 2}}
   (void) new T[n] {1, 2}; // expected-error {{no matching constructor}} expected-note {{in implicit initialization of trailing array elements in runtime-sized array new}}
+  (void) new T[n] {}; // expected-error {{no matching constructor}} expected-note {{in implicit initialization of trailing array elements in runtime-sized array new}}
 }
 
 struct U {