[clang-tools-extra] [clang-tidy] Add AllowReferencedInitialValues to `readability-enum-initial-value` (PR #189459)

[Björn Svensson via cfe-commits]

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@@ -0,0 +1,34 @@
+// RUN: %check_clang_tidy %s readability-enum-initial-value %t -- \
+// RUN:     -config='{CheckOptions: { \
+// RUN:         readability-enum-initial-value.AllowExplicitZeroFirstInitialValue: false, \
+// RUN:         readability-enum-initial-value.AllowExplicitSequentialInitialValues: false, \
+// RUN:         readability-enum-initial-value.AllowReferencedInitialValues: true, \
+// RUN:     }}'
+
+// Error: zero-first + self-ref, should still warn about the zero.
+enum EZeroRef {
+  EZeroRef_a = 0,
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: zero initial value for the first enumerator in 'EZeroRef' can be disregarded
+  // CHECK-FIXES: EZeroRef_a ,
+  EZeroRef_b,
+  EZeroRef_last = EZeroRef_b,
+};
+
+// Error: sequential + self-ref, should still warn but not suggest
+// removing the self-ref.
+enum ESeqRef {
+  // CHECK-MESSAGES: :[[@LINE-1]]:1: warning: sequential initial value in 'ESeqRef' can be ignored
+  ESeqRef_a = 1,
+  ESeqRef_b = 2,
+  // CHECK-FIXES: ESeqRef_b ,
+  ESeqRef_c = 3,
+  // CHECK-FIXES: ESeqRef_c ,
+  ESeqRef_alias = ESeqRef_a,
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bjosv wrote:

Done

https://github.com/llvm/llvm-project/pull/189459