Merge from latest antlr

.clang-format

@@ -0,0 +1,20 @@
+---
+# This section defines defaults for all languages. Currently we derive ANTLR style from LLVM.
+BasedOnStyle: LLVM
+# Only use clang-format for C++ for now.
+DisableFormat: true
+
+---
+# This section configures C++ formatting.
+Language: Cpp
+DisableFormat: false
+Standard: c++17
+# Prevent clang-format from attempting to pick the alignment and always use right alignment.
+DerivePointerAlignment: false
+# ANTLR existing style is to right align pointers and references.
+PointerAlignment: Right
+ReferenceAlignment: Right
+# Some of ANTLR existing code is longer than the default 80, so use 100 for now.
+ColumnLimit: 100
+# Historically ANTLR has used indentation within namespaces, so replicate it.
+NamespaceIndentation: Inner

.editorconfig

@@ -8,3 +8,11 @@ charset = utf-8
 insert_final_newline = true
 trim_trailing_whitespace = true
 indent_style = tab
+ij_java_else_on_new_line = true
+
+[*.{h,cpp}]
+charset = utf-8
+insert_final_newline = true
+trim_trailing_whitespace = true
+indent_style = space
+indent_size = 2

.gitattributes

@@ -1,2 +1,2 @@
 # This rule applies to all files which don't match another line below
-* text=auto
+* text=auto

.github/ISSUE_TEMPLATE.md

@@ -1,8 +1,15 @@
 <!--
-Before submitting an issue to ANTLR, please check off these boxes:
-
-- [ ] I am not submitting a question on how to use ANTLR; instead, go to [antlr4-discussion google group](https://groups.google.com/forum/#!forum/antlr-discussion) or ask at [stackoverflow](http://stackoverflow.com/questions/tagged/antlr4)
+All ANTLR contributors provide implementation, maintenance and support for free.
+We therefore kindly ask that before submitting any issue to ANTLR, you please check off these boxes:
+
+- [ ] I have reproduced my issue using the latest version of ANTLR
+- [ ] I have asked at [stackoverflow](http://stackoverflow.com/questions/tagged/antlr4)
+- [ ] Responses from the above seem to indicate that my issue could be an ANTLR bug
 - [ ] I have done a search of the existing issues to make sure I'm not sending in a duplicate
 
-Please include information about the expected behavior, actual behavior, and the smallest grammar or code that reproduces the behavior. If appropriate, please indicate the code generation targets such as Java, C#, ...  Pointers into offending code regions are also very welcome.
+Please include the following information:
+ - target information (Java, C++ ...)
+ - smallest possible grammar and code that reproduces the behavior
+ - description of the expected behavior and actual behavior
+Pointers to suspicious code regions are also very welcome.
 -->

.github/PULL_REQUEST_TEMPLATE.md

@@ -1,5 +1,23 @@
 <!--
-Thank you for proposing a contribution to the ANTLR project. In order to accept changes from the outside world, all contributors must "sign" the  [contributors.txt](https://github.com/antlr/antlr4/blob/master/contributors.txt) contributors certificate of origin. It's an unfortunate reality of today's fuzzy and bizarre world of open-source ownership.
+Thank you for proposing a contribution to the ANTLR project!
 
-Make sure you are already in the contributors.txt file or add a commit to this pull request with the appropriate change. Thanks!
--->
+(Please make sure your PR is in a branch other than dev or master
+ and also make sure that you derive this branch from dev.)
+
+As of 4.10, ANTLR uses the Linux Foundation's Developer
+Certificate of Origin, DCO, version 1.1. See either
+https://developercertificate.org/ or file 
+contributors-cert-of-origin.txt in the main directory.
+
+Each commit requires a "signature", which is simple as
+using `-s` (not `-S`) to the git commit command: 
+
+git commit -s -m 'This is my commit message'
+
+Github's pull request process enforces the sig and gives
+instructions on how to fix any commits that lack the sig.
+See https://github.com/apps/dco for more info.
+
+No signature is required in this file (unlike the
+previous ANTLR contributor's certificate of origin.)
+-->