1 files changed, 58 insertions, 0 deletions
diff --git a/tests/ui/parser/fn-header-semantic-fail.rs b/tests/ui/parser/fn-header-semantic-fail.rs
new file mode 100644
index 000000000..cf5d3dab4
--- /dev/null
+++ b/tests/ui/parser/fn-header-semantic-fail.rs
@@ -0,0 +1,58 @@
+// Ensures that all `fn` forms can have all the function qualifiers syntactically.
+
+// edition:2018
+
+#![feature(const_extern_fn)]
+
+fn main() {
+    async fn ff1() {} // OK.
+    unsafe fn ff2() {} // OK.
+    const fn ff3() {} // OK.
+    extern "C" fn ff4() {} // OK.
+    const async unsafe extern "C" fn ff5() {}
+    //~^ ERROR functions cannot be both `const` and `async`
+    //~| ERROR cycle detected
+
+    trait X {
+        async fn ft1(); //~ ERROR functions in traits cannot be declared `async`
+        unsafe fn ft2(); // OK.
+        const fn ft3(); //~ ERROR functions in traits cannot be declared const
+        extern "C" fn ft4(); // OK.
+        const async unsafe extern "C" fn ft5();
+        //~^ ERROR functions in traits cannot be declared `async`
+        //~| ERROR functions in traits cannot be declared const
+        //~| ERROR functions cannot be both `const` and `async`
+    }
+
+    struct Y;
+    impl X for Y {
+        async fn ft1() {} //~ ERROR functions in traits cannot be declared `async`
+        unsafe fn ft2() {} // OK.
+        const fn ft3() {} //~ ERROR functions in traits cannot be declared const
+        extern "C" fn ft4() {}
+        const async unsafe extern "C" fn ft5() {}
+        //~^ ERROR functions in traits cannot be declared `async`
+        //~| ERROR functions in traits cannot be declared const
+        //~| ERROR functions cannot be both `const` and `async`
+        //~| ERROR cycle detected
+    }
+
+    impl Y {
+        async fn fi1() {} // OK.
+        unsafe fn fi2() {} // OK.
+        const fn fi3() {} // OK.
+        extern "C" fn fi4() {} // OK.
+        const async unsafe extern "C" fn fi5() {}
+        //~^ ERROR functions cannot be both `const` and `async`
+        //~| ERROR cycle detected
+    }
+
+    extern "C" {
+        async fn fe1(); //~ ERROR functions in `extern` blocks cannot have qualifiers
+        unsafe fn fe2(); //~ ERROR functions in `extern` blocks cannot have qualifiers
+        const fn fe3(); //~ ERROR functions in `extern` blocks cannot have qualifiers
+        extern "C" fn fe4(); //~ ERROR functions in `extern` blocks cannot have qualifiers
+        const async unsafe extern "C" fn fe5(); //~ ERROR functions in `extern` blocks
+        //~^ ERROR functions cannot be both `const` and `async`
+    }
+}