Add test for trailing commas in parameter lists and argument lists.

tests/language/arg_param_trailing_comma_test.dart

+// Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+// Dart test program for testing params.
+
+// Convenience values.
+var c = new C();
+var x = 42;
+var y = 42;
+var z = 42;
+
+// Trailing comma in parameter litss.
+
+// Typedefs.
+typedef fx(x, );
+typedef fy([y,]);
+typedef fxy(x, [y, ]);
+typedef fz({z,});
+typedef fxz(x, {z, });
+
+// As arguments type.
+argfx(void f(x, )) {}
+argfy(void f([y, ])) {}
+argfxy(void f(x, [y, ])) {}
+argfz(void f({z, })) {}
+argfxz(void f(x, {z, })) {}
+
+// Top level functions
+void topx(x,) {}
+void topy([y, ]) {}
+void topxy(x, [y, ]) {}
+void topz({z, }) {}
+void topxz(x, {z, }) {}
+
+void set topsetx(x, ) {}
+
+// After specific parameter formats.
+void afterDefaultValueY([int y = 42, ]) {}
+void afterDefaultValueZ({int z : 42, }) {}
+void afterFunsigX(int f(),) {}
+void afterFunsigY([int f(),]) {}
+void afterFunsigZ({int f(),}) {}
+void afterFunctionSignatre([int f(), ]) {}
+
+class C {
+  C();
+
+  // Constructors.
+  C.x(x, );
+  C.y([y, ]);
+  C.xy(x, [y, ]);
+  C.z({z, });
+  C.xz(x, {z, });
+
+  // Static members
+  static void staticx(x,) {}
+  static void staticy([y, ]) {}
+  static void staticxy(x, [y, ]) {}
+  static void staticz({z, }) {}
+  static void staticxz(x, {z, }) {}
+
+  static void set staticsetx(x, ) {}
+
+  // Instance members
+  void instancex(x,) {}
+  void instancey([y, ]) {}
+  void instancexy(x, [y, ]) {}
+  void instancez({z, }) {}
+  void instancexz(x, {z, }) {}
+
+  void set instancesetx(x, ) {}
+
+  operator +(x, ) => this;
+  operator []=(x, y, ) {}
+}
+
+main(args, ) {
+  // Check that all functions can be called normally
+  topx(x);
+  topy(y);
+  topxy(x, y);
+  topz();
+  topz(z: z);
+  topxz(x);
+  topxz(x, z: z);
+  topsetx = x;
+  afterDefaultValueY();
+  afterDefaultValueY(y);
+  afterDefaultValueZ();
+  afterDefaultValueZ(z: z);
+  new C.x(x);
+  new C.xy(x);
+  new C.xy(x, y);
+  new C.y(y);
+  new C.xz(x);
+  new C.xz(x, z: z);
+  new C.z(z: z);
+  C.staticx(x);
+  C.staticy(y);
+  C.staticxy(x);
+  C.staticxy(x, y);
+  C.staticz();
+  C.staticz(z: z);
+  C.staticxz(x);
+  C.staticxz(x, z: z);
+  C.staticsetx = x;
+  c.instancex(x);
+  c.instancey();
+  c.instancey(y);
+  c.instancexy(x);
+  c.instancexy(x, y);
+  c.instancez();
+  c.instancez(z: z);
+  c.instancexz(x);
+  c.instancexz(x, z: z);
+  c.instancesetx = x;
+  c + x;
+  c[x] = y;
+
+  // Call with ekstra comma (not possible for setters and operators).

[hausner, 2016/06/22 17:19:41]

Dijkstra style comment :-)

[Lasse Reichstein Nielsen, 2016/06/24 11:50:55]

I regret nothing!

+  topx(x, );
+  topy(y, );
+  topxy(x, y, );
+  topxy(x, );
+  topz(z: z, );
+  topxz(x, );
+  topxz(x, z: z, );
+  new C.x(x, );
+  new C.xy(x, y, );
+  new C.xy(x, );
+  new C.y(y, );
+  new C.xz(x, );
+  new C.xz(x, z: z, );
+  new C.z(z: z, );
+  C.staticx(x, );
+  C.staticy(y, );
+  C.staticxy(x, y, );
+  C.staticxy(x, );
+  C.staticz(z: z, );
+  C.staticxz(x, );
+  C.staticxz(x, z: z, );
+  c.instancex(x, );
+  c.instancey(y, );
+  c.instancexy(x, y, );
+  c.instancexy(x, );
+  c.instancez(z: z, );
+  c.instancexz(x, );
+  c.instancexz(x, z: z, );
+
+  // Typedefs work.
+  if (topx is! fx) throw "Bad type: $fx";
+  if (topy is! fy) throw "Bad type: $fy";
+  if (topxy is! fxy) throw "Bad type: $fxy";
+  if (topz is! fz) throw "Bad type: $fz";
+  if (topxz is! fxz) throw "Bad type: $fxz";
+
+  // Parameter types work (checked mode only test).
+  argfx(topx);
+  argfy(topy);
+  argfxy(topxy);
+  argfz(topz);
+  argfxz(topxz);
+
+  // Make sure the Bad class is parsed.
+  new Bad().method();
+}
+
+
+// Invalid syntax
+void topBadEmpty(,) {}                           /// 01: compile-time error

[floitsch, 2016/06/22 18:23:38]

In theory, you would have a better test, if you only made the "," a compile time
error:

void topBadEmpty(
, /// 01: compile-time error
) {}

[Lasse Reichstein Nielsen, 2016/06/24 11:50:55]

True, that would ensure that some other unintended error doesn't make the test
succeed incorrectly.

I have tried doing that, but it is also much less readable.
Having one complete test per line makes it easier to figure out what is failing
when it fails.

It's also not all cases where it makes sense, e.g. "foo([,])" is invalid with
and without the comma.

+void topBadStart(, a) {}                         /// 02: compile-time error
+void topBadEnd(a,,) {}                           /// 03: compile-time error
+void topBadMiddle(a,, b) {}                      /// 04: compile-time error
+void topBadPosEmpty([,]) {}                      /// 01: compile-time error
+void topBadPosStart([, a]) {}                    /// 02: compile-time error
+void topBadPosEnd([a,,]) {}                      /// 03: compile-time error
+void topBadPosMiddle({a,, b}) {}                 /// 04: compile-time error
+void topBadPosEmpty({,}) {}                      /// 01: compile-time error
+void topBadPosStart({, a}) {}                    /// 02: compile-time error
+void topBadPosEnd({a,,}) {}                      /// 03: compile-time error
+void topBadPosMiddle([a,, b]) {}                 /// 04: compile-time error
+void set topSetBadEmpty(,) {}                    /// 05: compile-time error
+void set topSetBadStart(, a) {}                  /// 06: compile-time error
+void set topSetBadEnd(a,,) {}                    /// 07: compile-time error
+void set topSetBadMiddle(a,, b) {}               /// 08: compile-time error
+class Bad {
+  Bad.empty(,) {}                                /// 09: compile-time error
+  Bad.start(, a) {}                              /// 10: compile-time error
+  Bad.end(a,,) {}                                /// 11: compile-time error
+  Bad.middle(a,, b) {}                           /// 12: compile-time error
+  static staticBadEmpty(,) {}                    /// 13: compile-time error
+  static staticBadStart(, a) {}                  /// 14: compile-time error
+  static staticBadEnd(a,,) {}                    /// 15: compile-time error
+  static staticBadMiddle(a,, b) {}               /// 16: compile-time error
+  static void set staticSetBadEmpty(,) {}        /// 17: compile-time error
+  static void set staticSetBadStart(, a) {}      /// 18: compile-time error
+  static void set staticSetBadEnd(a,,) {}        /// 19: compile-time error
+  static void set staticSetBadMiddle(a,, b) {}   /// 20: compile-time error
+  instanceBadEmpty(,) {}                         /// 21: compile-time error
+  instanceBadStart(, a) {}                       /// 22: compile-time error
+  instanceBadEnd(a,,) {}                         /// 23: compile-time error
+  instanceBadMiddle(a,, b) {}                    /// 24: compile-time error
+  void set instanceSetBadEmpty(,) {}             /// 25: compile-time error
+  void set instanceSetBadStart(, a) {}           /// 26: compile-time error
+  void set instanceSetBadEnd(a,,) {}             /// 27: compile-time error
+  void set instanceSetBadMiddle(a,, b) {}        /// 28: compile-time error
+  void operator *(,);                            /// 29: compile-time error
+  void operator *(, a);                          /// 30: compile-time error
+  void operator *(a,,);                          /// 31: compile-time error
+  void operator []=(, a);                        /// 32: compile-time error
+  void operator []=(a,,);                        /// 33: compile-time error
+  void operator []=(a,, b);                      /// 34: compile-time error
+  void operator []=(a,);                         /// 35: compile-time error
+
+  method() {
+    // invalid calls.
+
+    topx(,);                                     /// 36: compile-time error
+    topy(,);                                     /// 37: compile-time error
+    topz(,);                                     /// 38: compile-time error
+    topx(, x);                                   /// 39: compile-time error
+    topz(, z:z);                                 /// 40: compile-time error
+    topxy(x,, y);                                /// 41: compile-time error
+    topxz(x,, z:z);                              /// 42: compile-time error
+    topx(x,,);                                   /// 43: compile-time error
+    topz(z:z,,);                                 /// 44: compile-time error
+
+    new C.x(,);                                  /// 45: compile-time error
+    new C.y(,);                                  /// 46: compile-time error
+    new C.z(,);                                  /// 47: compile-time error
+    new C.x(, x);                                /// 48: compile-time error
+    new C.z(, z:z);                              /// 49: compile-time error
+    new C.xy(x,, y);                             /// 50: compile-time error
+    new C.xz(x,, z:z);                           /// 51: compile-time error
+    new C.x(x,,);                                /// 52: compile-time error
+    new C.z(z:z,,);                              /// 53: compile-time error
+
+    C.staticx(,);                                /// 54: compile-time error
+    C.staticy(,);                                /// 55: compile-time error
+    C.staticz(,);                                /// 56: compile-time error
+    C.staticx(, x);                              /// 57: compile-time error
+    C.staticz(, z:z);                            /// 58: compile-time error
+    C.staticxy(x,, y);                           /// 59: compile-time error
+    C.staticxz(x,, z:z);                         /// 60: compile-time error
+    C.staticx(x,,);                              /// 61: compile-time error
+    C.staticz(z:z,,);                            /// 62: compile-time error
+
+    c.instancex(,);                              /// 63: compile-time error
+    c.instancey(,);                              /// 64: compile-time error
+    c.instancez(,);                              /// 65: compile-time error
+    c.instancex(, x);                            /// 66: compile-time error
+    c.instancez(, z:z);                          /// 67: compile-time error
+    c.instancexy(x,, y);                         /// 68: compile-time error
+    c.instancexz(x,, z:z);                       /// 69: compile-time error
+    c.instancex(x,,);                            /// 70: compile-time error
+    c.instancez(z:z,,);                          /// 71: compile-time error
+
+    c[x,] = y;                                   /// 72: compile-time error
+  }
+}