From 208661b206be29c02f1e39ef00263f5efcd05a49 Mon Sep 17 00:00:00 2001
From: Nico Weber <nicolasweber@gmx.de>
Date: Fri, 5 Oct 2018 18:22:21 +0000
Subject: [PATCH] clang-format: Don't insert spaces in front of :: for Java 8
 Method References.

The existing code kept the space if it was there for identifiers, and it didn't
handle `this`. After this patch, for Java `this` is handled in addition to
identifiers, and existing space is always stripped between identifier and `::`.

Also accept `::` in addition to `.` in front of `<` in `foo::<T>bar` generic
calls.

Differential Revision: https://reviews.llvm.org/D52842

llvm-svn: 343872
---
 clang/lib/Format/TokenAnnotator.cpp       |  8 +++++++-
 clang/unittests/Format/FormatTestJava.cpp | 16 ++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 2cb4c0361b9d..d032fd7cb95b 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2555,8 +2555,11 @@ bool TokenAnnotator::spaceRequiredBetween(const AnnotatedLine &Line,
     return false;
   if (Left.is(TT_TemplateCloser) && Left.MatchingParen &&
       Left.MatchingParen->Previous &&
-      Left.MatchingParen->Previous->is(tok::period))
+      (Left.MatchingParen->Previous->is(tok::period) ||
+       Left.MatchingParen->Previous->is(tok::coloncolon)))
+    // Java call to generic function with explicit type:
     // A.<B<C<...>>>DoSomething();
+    // A::<B<C<...>>>DoSomething();  // With a Java 8 method reference.
     return false;
   if (Left.is(TT_TemplateCloser) && Right.is(tok::l_square))
     return false;
@@ -2776,6 +2779,9 @@ bool TokenAnnotator::spaceRequiredBefore(const AnnotatedLine &Line,
   if (!Style.SpaceBeforeAssignmentOperators &&
       Right.getPrecedence() == prec::Assignment)
     return false;
+  if (Style.Language == FormatStyle::LK_Java && Right.is(tok::coloncolon) &&
+      (Left.is(tok::identifier) || Left.is(tok::kw_this)))
+    return false;
   if (Right.is(tok::coloncolon) && Left.is(tok::identifier))
     // Generally don't remove existing spaces between an identifier and "::".
     // The identifier might actually be a macro name such as ALWAYS_INLINE. If
diff --git a/clang/unittests/Format/FormatTestJava.cpp b/clang/unittests/Format/FormatTestJava.cpp
index 76e82612e0fe..aee8a993fe60 100644
--- a/clang/unittests/Format/FormatTestJava.cpp
+++ b/clang/unittests/Format/FormatTestJava.cpp
@@ -443,6 +443,22 @@ TEST_F(FormatTestJava, MethodDeclarations) {
                getStyleWithColumns(40));
 }
 
+TEST_F(FormatTestJava, MethodReference) {
+  EXPECT_EQ(
+      "private void foo() {\n"
+      "  f(this::methodReference);\n"
+      "  f(C.super::methodReference);\n"
+      "  Consumer<String> c = System.out::println;\n"
+      "  Iface<Integer> mRef = Ty::<Integer>meth;\n"
+      "}",
+      format("private void foo() {\n"
+             "  f(this ::methodReference);\n"
+             "  f(C.super ::methodReference);\n"
+             "  Consumer<String> c = System.out ::println;\n"
+             "  Iface<Integer> mRef = Ty :: <Integer> meth;\n"
+             "}"));
+}
+
 TEST_F(FormatTestJava, CppKeywords) {
   verifyFormat("public void union(Type a, Type b);");
   verifyFormat("public void struct(Object o);");