[clang] Check if clang::FieldDecl has constant-integer bit width before getting the width (PR #148692)

[Shafik Yaghmour via cfe-commits]

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@@ -709,7 +709,8 @@ AST_MATCHER(FieldDecl, isBitField) {
 /// fieldDecl(hasBitWidth(2))
 ///   matches 'int a;' and 'int c;' but not 'int b;'.
 AST_MATCHER_P(FieldDecl, hasBitWidth, unsigned, Width) {
-  return Node.isBitField() && Node.getBitWidthValue() == Width;
+  return Node.isBitField() && Node.hasConstantIntegerBitWidth() &&
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shafik wrote:

It looks like you are only testing the `Node.hasConstantIntegerBitWidth() == true` case in the test below. If that is correct we should add a test that covers both cases and any other combinations of these conditions not covered by testing.

https://github.com/llvm/llvm-project/pull/148692