[clang] 9b68c09 - [clang-format] Allow decltype in requires clause (#78847)

[via cfe-commits]

Author: Emilia Kond
Date: 2024-02-01T08:00:45+02:00
New Revision: 9b68c095d6b52d6ec0390c653528f65c42e5f570

URL: https://github.com/llvm/llvm-project/commit/9b68c095d6b52d6ec0390c653528f65c42e5f570
DIFF: https://github.com/llvm/llvm-project/commit/9b68c095d6b52d6ec0390c653528f65c42e5f570.diff

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

If clang-format is not sure whether a `requires` keyword starts a
requires clause or a requires expression, it looks ahead to see if any
token disqualifies it from being a requires clause. Among these tokens
was `decltype`, since it fell through the switch.

This patch allows decltype to exist in a require clause.

I'm not 100% sure this change won't have repercussions, but that just
means we need more test coverage!

Fixes https://github.com/llvm/llvm-project/issues/78645

Added: 
    

Modified: 
    clang/lib/Format/UnwrappedLineParser.cpp
    clang/unittests/Format/TokenAnnotatorTest.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Format/UnwrappedLineParser.cpp b/clang/lib/Format/UnwrappedLineParser.cpp
index b904e0e56d9eb..0a7f8808f29af 100644
--- a/clang/lib/Format/UnwrappedLineParser.cpp
+++ b/clang/lib/Format/UnwrappedLineParser.cpp
@@ -3446,11 +3446,6 @@ bool clang::format::UnwrappedLineParser::parseRequires() {
         return false;
       }
       break;
-    case tok::r_paren:
-    case tok::pipepipe:
-      FormatTok = Tokens->setPosition(StoredPosition);
-      parseRequiresClause(RequiresToken);
-      return true;
     case tok::eof:
       // Break out of the loop.
       Lookahead = 50;
@@ -3458,6 +3453,7 @@ bool clang::format::UnwrappedLineParser::parseRequires() {
     case tok::coloncolon:
       LastWasColonColon = true;
       break;
+    case tok::kw_decltype:
     case tok::identifier:
       if (FoundType && !LastWasColonColon && OpenAngles == 0) {
         FormatTok = Tokens->setPosition(StoredPosition);

diff  --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index f3e443e8829bd..6e5832858c1ec 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -1076,6 +1076,28 @@ 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);
+
+  Tokens = annotate("bool x = t && requires(decltype(t) x) { x.foo(); };");
+  ASSERT_EQ(Tokens.size(), 23u) << Tokens;
+  EXPECT_TOKEN(Tokens[5], tok::kw_requires, TT_RequiresExpression);
+
+  Tokens = annotate("bool x = t && requires(Foo<decltype(t)> x) { x.foo(); };");
+  ASSERT_EQ(Tokens.size(), 26u) << Tokens;
+  EXPECT_TOKEN(Tokens[5], tok::kw_requires, TT_RequiresExpression);
+
+  Tokens = annotate("bool x = t && requires(Foo<C1 || C2> x) { x.foo(); };");
+  ASSERT_EQ(Tokens.size(), 25u) << Tokens;
+  EXPECT_TOKEN(Tokens[5], tok::kw_requires, TT_RequiresExpression);
 }
 
 TEST_F(TokenAnnotatorTest, UnderstandsRequiresExpressions) {