Address review comments

Author: kovdan01

llvm/lib/FileCheck/FileCheck.cpp

@@ -298,7 +298,7 @@ Pattern::parseVariable(StringRef &Str, const SourceMgr &SM) {
     ++I;
 
   if (I == Str.size())
-    return ErrorDiagnostic::get(SM, Str,
+    return ErrorDiagnostic::get(SM, Str.slice(I, StringRef::npos),
                                 StringRef("empty ") +
                                     (IsPseudo ? "pseudo " : "global ") +
                                     "variable name");

llvm/test/FileCheck/empty-variable-name.txt

@@ -7,7 +7,7 @@ a
 ; CHECK:        a[[]]
 ; CHECK-ERROR:[[DIR]]/empty-variable-name.txt:7:13: error: empty variable name
 ; CHECK-ERROR-NEXT:; CHECK: a{{\[\[\]\]}}
-; CHECK-ERROR-NEXT:            ^
+;      CHECK-ERROR-NEXT:            ^
 
 b
 
@@ -16,9 +16,9 @@ b
 ; RUN:   --match-full-lines --strict-whitespace %s
 
 ; CHECK-PSEUDO: b[[@]]
-; CHECK-ERROR-PSEUDO:[[DIR]]/empty-variable-name.txt:18:20: error: empty pseudo variable name
+; CHECK-ERROR-PSEUDO:[[DIR]]/empty-variable-name.txt:18:21: error: empty pseudo variable name
 ; CHECK-ERROR-PSEUDO-NEXT:; CHECK-PSEUDO: b{{\[\[@\]\]}}
-; CHECK-ERROR-PSEUDO-NEXT:                   ^
+;      CHECK-ERROR-PSEUDO-NEXT:                    ^
 
 c
 
@@ -27,6 +27,6 @@ c
 ; RUN:   --match-full-lines --strict-whitespace %s
 
 ; CHECK-GLOBAL: c[[$]]
-; CHECK-ERROR-GLOBAL:[[DIR]]/empty-variable-name.txt:29:20: error: empty global variable name
+; CHECK-ERROR-GLOBAL:[[DIR]]/empty-variable-name.txt:29:21: error: empty global variable name
 ; CHECK-ERROR-GLOBAL-NEXT:; CHECK-GLOBAL: c{{\[\[\$\]\]}}
-; CHECK-ERROR-GLOBAL-NEXT:                   ^
+;       CHECK-ERROR-GLOBAL-NEXT:                    ^