* commit '6427f5a1':
  Fixed casts in foreign Dqrdc2.

Merge pull request #693 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/check_arg_not_null to master

* commit 'ef0b63e3':
  check that arguments are not null

rffi; replace UpCallsIndex with RFFIUpCallMethod enum; fix bug in R_NewHashedEnv signature; simplify RForeignAccessFactoryImpl

* commit '61ca40d4':
  rffi(llvm): all access to global variables via upcalls; fixes from DLLRFFI change

Merge pull request #691 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:fix/graphics-new-casts to master

* commit '8c795f2a':
  Fix termsform with formulae without LHS
  Convert graphics related nodes to new casts system

Merge pull request #692 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:bugfix/truffleboundary_valueprinter to master

* commit '75afb454':
  add missing TruffleBoundary in ValuePrinterNode

Merge pull request #690 in G/fastr from ~FLORIAN.ANGERER_ORACLE.COM/fastr:bugfix/virtualframe to master

* commit 'e90d9ce0':
  Fixed compilation error due to removed import (see PR-687)

Merge pull request #687 in G/fastr from ~FLORIAN.ANGERER_ORACLE.COM/fastr:maintenance/frameparam to master

* commit '8d9f07e9':
  Adapted to changes in GR-1767: frame parameter removed from interop functions and transitively from all callers where possible. Also updated Truffle version in file "suite.py". Removed class TruffleRFFIFrameHelper since there are no usages any longer. Removed unnecessary call to CompilerDirectives.transferToInterpreter call in class ValuePrinterNode.

Merge pull request #674 in G/fastr from ~MILOSLAV.METELKA_ORACLE.COM/fastr:R6ClassInternalError to master

* commit '8a2607fb':
  Fixed R6Class() to pass without internal errors.

Adapted to changes in GR-1767: frame parameter removed from interop functions and transitively from all callers where possible.
Also updated Truffle version in file "suite.py".
Removed class TruffleRFFIFrameHelper since there are no usages any longer.
Removed unnecessary call to CompilerDirectives.transferToInterpreter call in class ValuePrinterNode.

* commit '76c6ecab':
  rffi: minor cleanup

Merge pull request #676 in G/fastr from ~STEPAN.SINDELAR_ORACLE.COM/fastr:fix/symbol-eq-args-matching to master

* commit 'cf846431':
  Argument matching: first by exact name and only then by partial
  Deparse in BinaryBooleanNode removes backticks, e.g. around `+`

Merge pull request #685 in G/fastr from ~FLORIAN.ANGERER_ORACLE.COM/fastr:improvement/save-session to master

* commit '1ea315a4':
  Implemented improvement preventing a previously stored session to be destroyed by TestBuiltin_quit.

* commit 'd061d28b':
  Cast pipelines made static

Merge pull request #680 in G/fastr from ~LUKAS.STADLER_ORACLE.COM/fastr:feature/update_truffle to master

* commit '27ce8836':
  update Truffle version

Merge pull request #682 in G/fastr from ~FLORIAN.ANGERER_ORACLE.COM/fastr:bugfix/emptyworkspace to master

* commit '0cbd8000':
  Sessions could not be save for empty workspaces since LoadSaveFunctions.SaveToConn expected a non-empty list of variables to store. However, GnuR allows to do so. Also fixed problem when using function "q()" in test cases which caused the test suite to crash due to an unexpected but legitimate exception.

Sessions could not be save for empty workspaces since LoadSaveFunctions.SaveToConn expected a non-empty list of variables to store. However, GnuR allows to do so.
Also fixed problem when using function "q()" in test cases which caused the test suite to crash due to an unexpected but legitimate exception.