diff --git a/src/compiletest/header.rs b/src/compiletest/header.rs
index 2413a001ee8..374fd2e3ef0 100644
--- a/src/compiletest/header.rs
+++ b/src/compiletest/header.rs
@@ -42,6 +42,8 @@ pub struct TestProps {
     pub pretty_compare_only: bool,
     // Patterns which must not appear in the output of a cfail test.
     pub forbid_output: Vec<String>,
+    // Ignore errors which originate from a command line span
+    pub ignore_command_line: bool,
 }
 
 // Load any test directives embedded in the file
@@ -60,6 +62,8 @@ pub fn load_props(testfile: &Path) -> TestProps {
     let mut pretty_mode = None;
     let mut pretty_compare_only = false;
     let mut forbid_output = Vec::new();
+    let mut ignore_command_line = false;
+
     iter_header(testfile, |ln| {
         match parse_error_pattern(ln) {
           Some(ep) => error_patterns.push(ep),
@@ -102,6 +106,10 @@ pub fn load_props(testfile: &Path) -> TestProps {
             pretty_compare_only = parse_pretty_compare_only(ln);
         }
 
+        if !ignore_command_line {
+            ignore_command_line = parse_ignore_command_line(ln);
+        }
+
         match parse_aux_build(ln) {
             Some(ab) => { aux_builds.push(ab); }
             None => {}
@@ -140,6 +148,7 @@ pub fn load_props(testfile: &Path) -> TestProps {
         pretty_mode: pretty_mode.unwrap_or("normal".to_string()),
         pretty_compare_only: pretty_compare_only,
         forbid_output: forbid_output,
+        ignore_command_line: ignore_command_line,
     }
 }
 
@@ -291,6 +300,10 @@ fn parse_pretty_compare_only(line: &str) -> bool {
     parse_name_directive(line, "pretty-compare-only")
 }
 
+fn parse_ignore_command_line(line: &str) -> bool {
+    parse_name_directive(line, "ignore-command-line")
+}
+
 fn parse_exec_env(line: &str) -> Option<(String, String)> {
     parse_name_value_directive(line, "exec-env").map(|nv| {
         // nv is either FOO or FOO=BAR
diff --git a/src/compiletest/runtest.rs b/src/compiletest/runtest.rs
index 5de93c52029..a97d4913440 100644
--- a/src/compiletest/runtest.rs
+++ b/src/compiletest/runtest.rs
@@ -104,7 +104,7 @@ fn run_cfail_test(config: &Config, props: &TestProps, testfile: &Path) {
         if !props.error_patterns.is_empty() {
             fatal("both error pattern and expected errors specified");
         }
-        check_expected_errors(expected_errors, testfile, &proc_res);
+        check_expected_errors(props, expected_errors, testfile, &proc_res);
     } else {
         check_error_patterns(props, testfile, output_to_check.as_slice(), &proc_res);
     }
@@ -941,7 +941,8 @@ fn check_forbid_output(props: &TestProps,
     }
 }
 
-fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
+fn check_expected_errors(props: &TestProps,
+                         expected_errors: Vec<errors::ExpectedError> ,
                          testfile: &Path,
                          proc_res: &ProcRes) {
 
@@ -996,6 +997,11 @@ fn check_expected_errors(expected_errors: Vec<errors::ExpectedError> ,
             was_expected = true;
         }
 
+        if line.starts_with("<command line option>") &&
+           props.ignore_command_line {
+            was_expected = true;
+        }
+
         if !was_expected && is_compiler_error_or_warning(line) {
             fatal_proc_rec(format!("unexpected compiler error or warning: '{}'",
                                   line).as_slice(),
diff --git a/src/test/compile-fail/recursion.rs b/src/test/compile-fail/recursion.rs
index da05514f763..de326677c86 100644
--- a/src/test/compile-fail/recursion.rs
+++ b/src/test/compile-fail/recursion.rs
@@ -8,7 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-//~^^^^^^^^^^ ERROR overflow
+// ignore-command-line: See https://github.com/rust-lang/rust/issues/20747
 //
 // We also get a second error message at the top of file (dummy
 // span). This is not helpful, but also kind of annoying to prevent,