When copying whitespace flags from the token naming a macro argument onto the

first token of the expansion, don't forget to copy the "is at the start of a
line" token (which is always false, as newlines cannot appear within a macro
body); otherwise, stringizing the result can insert spurious whitespace.

llvm-svn: 257863

clang/lib/Lex/TokenLexer.cpp

@@ -305,6 +305,7 @@ void TokenLexer::ExpandFunctionArguments() {
         // identifier.
         ResultToks[FirstResult].setFlagValue(Token::LeadingSpace,
                                              NextTokGetsSpace);
+        ResultToks[FirstResult].setFlagValue(Token::StartOfLine, false);
         NextTokGetsSpace = false;
       }
       continue;

clang/test/Preprocessor/stringize_space.c

@@ -12,3 +12,9 @@ c)
 
 // CHECK: {{^}}"a c"{{$}}
 
+#define str(x) #x
+#define f(x) str(-x)
+f(
+    1)
+
+// CHECK: {{^}}"-1"