Fix off-by-one error when emitting diagnostics.  Also, make diagnostic
a bit nicer for people who pass lots of extra arguments to calls by 
selecting them all instead of just the first one:

arg-duplicate.c:13:13: error: too many arguments to function
  f3 (1, 1, 2, 3, 4);   // expected-error {{too many arguments to function}}
            ^~~~~~~

This implements test/Sema/arg-duplicate.c, thanks to Neil for pointing
out this crash.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@40136 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Sema/arg-duplicate.c b/test/Sema/arg-duplicate.c
new file mode 100644
index 0000000..5d44a72
--- /dev/null
+++ b/test/Sema/arg-duplicate.c
@@ -0,0 +1,15 @@
+// RUN: clang -parse-ast-check %s
+
+typedef int x; 
+int f3(y, x, 
+       x)          // expected-error {{redefinition of parameter}}
+  int y, x, 
+      x;           // expected-error {{redefinition of parameter}}
+{
+  return x + y; 
+} 
+
+void f4(void) { 
+  f3 (1, 1, 2, 3, 4);   // expected-error {{too many arguments to function}}
+}
+