[clang] [clang-format] Allow decltype in requires clause (PR #78847)

[Emilia Kond via cfe-commits]

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@@ -1071,6 +1071,16 @@ TEST_F(TokenAnnotatorTest, UnderstandsRequiresClausesAndConcepts) {
                     "concept C = (!Foo<T>) && Bar;");
   ASSERT_EQ(Tokens.size(), 19u) << Tokens;
   EXPECT_TOKEN(Tokens[15], tok::ampamp, TT_BinaryOperator);
+
+  Tokens = annotate("void f() & requires(C<decltype(x)>) {}");
+  ASSERT_EQ(Tokens.size(), 18u) << Tokens;
+  EXPECT_TOKEN(Tokens[4], tok::amp, TT_PointerOrReference);
+  EXPECT_TOKEN(Tokens[5], tok::kw_requires, TT_RequiresClause);
+
+  Tokens = annotate("auto f() -> int& requires(C<decltype(x)>) {}");
+  ASSERT_EQ(Tokens.size(), 20u) << Tokens;
+  EXPECT_TOKEN(Tokens[6], tok::amp, TT_PointerOrReference);
+  EXPECT_TOKEN(Tokens[7], tok::kw_requires, TT_RequiresClause);
 }
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rymiel wrote:

> If I read the code right my question is why didn't `Foo<decktype(t)>` suffice `FoundType && !LastWasColonColon && OpenAngles == 0` when hitting the `x`?

I'm not sure what you mean. If you're talking about `Foo<decltype(t)> x`, it never gets to the `x` because it reaches the `)` of the decltype first and that unconditionally leads to being parsed as a clause

https://github.com/llvm/llvm-project/pull/78847