Fix clang-format's detection of structured bindings.

Correctly determine when [ is part of a structured binding instead of a
lambda.

To be able to reuse the implementation already available, this patch also:
- sets the Previous link of FormatTokens in the UnwrappedLineParser
- moves the isCppStructuredBinding function into FormatToken

Before:
  auto const const &&[x, y] { A *i };

After:
  auto const const && [x, y]{A * i};

Fixing formatting of the type of the structured binding is still missing.

llvm-svn: 313742

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/unittests/Format/FormatTest.cpp b/clang/unittests/Format/FormatTest.cpp
index 34206e9e418..a1b0e5fee74 100644
--- a/clang/unittests/Format/FormatTest.cpp
+++ b/clang/unittests/Format/FormatTest.cpp
@@ -11588,6 +11588,11 @@ TEST_F(FormatTest, StructuredBindings) {
             format("auto  const  volatile  &&[a, b] = f();"));
   EXPECT_EQ("auto && [a, b] = f();", format("auto  &&[a, b] = f();"));
 
+  // Make sure we don't mistake structured bindings for lambdas.
+  verifyFormat("auto [a, b]{A * i};");
+  verifyFormat("auto const [a, b]{A * i};");
+  verifyFormat("auto const && [a, b]{A * i};");
+
   format::FormatStyle Spaces = format::getLLVMStyle();
   Spaces.SpacesInSquareBrackets = true;
   verifyFormat("auto [ a, b ] = f();", Spaces);