[clang] [clang-cl] Fix value of __FUNCTION__ in MSVC mode. (PR #84014)

[Aaron Ballman via cfe-commits]

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@@ -1635,6 +1635,17 @@ void TypePrinter::printElaboratedBefore(const ElaboratedType *T,
     if (T->getKeyword() != ElaboratedTypeKeyword::None)
       OS << " ";
     NestedNameSpecifier *Qualifier = T->getQualifier();
+    if (!Policy.SuppressTagKeyword && Policy.SuppressScope &&
+        !Policy.SuppressUnwrittenScope) {
+      StringRef prefix = T->isClassType()       ? "class "
+                         : T->isStructureType() ? "struct "
+                         : T->isUnionType()     ? "union "
+                                                : "";
+      OS << prefix;
+      Policy.SuppressTagKeyword = true;
+      Policy.SuppressScope = false;
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AaronBallman wrote:

The code was broken but no tests failed, then the fix you made was also broken but still no tests failed. So I'm asking you to write a new test that demonstrates incorrect behavior related to failing to reset the printing policy after modifying it, then fix the code until that test shows the correct behavior.

https://github.com/llvm/llvm-project/pull/84014