[FileCheck] Make NumericVariable ctor explicit

Summary:
Make FileCheckNumericVariable constructor explicit to avoid implicit
conversions from StringRef.

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66640

llvm-svn: 370664

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/include/llvm/Support/FileCheck.h b/llvm/include/llvm/Support/FileCheck.h
index 149666157a6..34301f92bcb 100644
--- a/llvm/include/llvm/Support/FileCheck.h
+++ b/llvm/include/llvm/Support/FileCheck.h
@@ -109,8 +109,8 @@ private:
 public:
   /// Constructor for a variable \p Name defined at line \p DefLineNumber or
   /// defined before input is parsed if \p DefLineNumber is None.
-  FileCheckNumericVariable(StringRef Name,
-                           Optional<size_t> DefLineNumber = None)
+  explicit FileCheckNumericVariable(StringRef Name,
+                                    Optional<size_t> DefLineNumber = None)
       : Name(Name), DefLineNumber(DefLineNumber) {}
 
   /// \returns name of this numeric variable.