End the deprecation period of using the result of a comma expression.

Author: wilzbach

changelog/comma-deprecation-error.dd

@@ -0,0 +1,4 @@
+The deprecation period of using the result of comma expression has ended
+
+Comma expressions have proven to be a frequent source of confusion, and bugs.
+Using their result will now trigger an error message.

src/dmd/expressionsem.d

@@ -5844,7 +5844,7 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
 
         e.type = e.e2.type;
         if (e.type !is Type.tvoid && !e.allowCommaExp && !e.isGenerated)
-            e.deprecation("Using the result of a comma expression is deprecated");
+            e.error("The result of a comma expression cant be used");
         result = e;
     }
 
@@ -6272,7 +6272,7 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             /* Rewrite to get rid of the comma from rvalue
              */
             if (!(cast(CommaExp)exp.e2).isGenerated)
-                exp.deprecation("Using the result of a comma expression is deprecated");
+                exp.error("The result of a comma expression cant be used");
             Expression e0;
             exp.e2 = Expression.extractLast(exp.e2, &e0);
             Expression e = Expression.combine(e0, exp);

test/fail_compilation/commaexp.d

@@ -1,13 +1,13 @@
-/* REQUIRED_ARGS: -o- -de
+/* REQUIRED_ARGS: -o-
 TEST_OUTPUT:
 ---
-fail_compilation/commaexp.d(24): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(36): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(37): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(38): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(39): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(41): Deprecation: Using the result of a comma expression is deprecated
-fail_compilation/commaexp.d(42): Deprecation: Using the result of a comma expression is deprecated
+fail_compilation/commaexp.d(24): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(36): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(37): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(38): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(39): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(41): Error: The result of a comma expression cant be used
+fail_compilation/commaexp.d(42): Error: The result of a comma expression cant be used
 ---
 */
 

test/fail_compilation/diag10862.d

@@ -57,7 +57,7 @@ fail_compilation/diag10862.d(77): Error: assignment cannot be used as a conditio
 fail_compilation/diag10862.d-mixin-80(80): Error: assignment cannot be used as a condition, perhaps `==` was meant?
 fail_compilation/diag10862.d-mixin-81(81): Error: assignment cannot be used as a condition, perhaps `==` was meant?
 fail_compilation/diag10862.d-mixin-82(82): Error: assignment cannot be used as a condition, perhaps `==` was meant?
-fail_compilation/diag10862.d-mixin-83(83): Deprecation: Using the result of a comma expression is deprecated
+fail_compilation/diag10862.d-mixin-83(83): Error: The result of a comma expression cant be used
 fail_compilation/diag10862.d-mixin-83(83): Error: assignment cannot be used as a condition, perhaps `==` was meant?
 fail_compilation/diag10862.d-mixin-86(86): Error: `a + b` is not an lvalue
 fail_compilation/diag10862.d-mixin-87(87): Error: undefined identifier `c`

test/fail_compilation/ice10949.d

@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice10949.d(12): Deprecation: Using the result of a comma expression is deprecated
+fail_compilation/ice10949.d(12): Error: the result of a comma expression cant be used
 fail_compilation/ice10949.d(12): Error: array index 3 is out of bounds `[5, 5][0 .. 2]`
 fail_compilation/ice10949.d(12): Error: array index 17 is out of bounds `[2, 3][0 .. 2]`
 fail_compilation/ice10949.d(12):        while evaluating: `static assert((((([5, 5][3] + global - global) * global / global % global >> global & global | global) ^ global) == 9 , [2, 3][17]) || [3, 3, 3][9] is 4 && [[1, 2, 3]][4].length)`

test/runnable/ctorpowtests.d

@@ -136,7 +136,8 @@ static assert(bazra(14)==64);
 
 void moreCommaTests()
 {
-   auto k = (containsAsm(), containsAsm());
+   (containsAsm(), containsAsm());
+   auto k = containsAsm();
    for (int i=0; i< k^^2; i+=StructWithCtor(1).n) {}
 }
 

test/runnable/lazy.d

@@ -74,7 +74,7 @@ void test1()
     );
 
     whiler( x < 100,
-        (printf("%d\n", x), x *= 2)
+        (){ printf("%d\n", x); x *= 2; }()
     );
 }
 

test/runnable/sdtor.d

@@ -879,7 +879,9 @@ void test34()
     X34[2] xs;
 //  xs[0][0] = X34();
     printf("foreach\n");
-    for (int j = 0; j < xs.length; j++) { auto x = (j++,j--,xs[j]);
+    for (int j = 0; j < xs.length; j++) {
+        j++,j--;
+        auto x = xs[j];
         //foreach(x; xs) {
         //printf("foreach x.i = %d\n", x[0].i);
         //assert(x[0].i == 1);
@@ -1395,22 +1397,22 @@ void test54()
     assert(S54.t == "c");
 
     {   S54.t = null;
-        int b = 1 && (bar54(S54(1)), 1);
+        int b = 1 && (){ bar54(S54(1)); return 1;}();
     }
     assert(S54.t == "ac");
 
     {   S54.t = null;
-        int b = 0 && (bar54(S54(1)), 1);
+        int b = 0 && (){ bar54(S54(1)); return 1;}();
     }
     assert(S54.t == "");
 
     {   S54.t = null;
-        int b = 0 || (bar54(S54(1)), 1);
+        int b = 0 || (){ bar54(S54(1)); return 1;}();
     }
     assert(S54.t == "ac");
 
     {   S54.t = null;
-        int b = 1 || (bar54(S54(1)), 1);
+        int b = 1 || (){ bar54(S54(1)); return 1;}();
     }
     assert(S54.t == "");
 
@@ -1529,7 +1531,8 @@ void test57()
 
     printf("----\n");    //+
     dtor_cnt = 0;
-    if (auto s = (S57(1), S57(2), S57(10)))
+    S57(1), S57(2);
+    if (auto s = S57(10))
     {
         assert(dtor_cnt == 2);
         printf("ifbody\n");
@@ -1562,7 +1565,8 @@ void test57()
 
     printf("----\n");    //+
     dtor_cnt = 0;
-    if (auto s = (f(1), f(2), f(10)))
+    f(1), f(2);
+    if (auto s = f(10))
     {
         assert(dtor_cnt == 2);
         printf("ifbody\n");
@@ -1596,7 +1600,8 @@ void test57()
 
     printf("----\n");
     dtor_cnt = 0;
-    if ((S57(1), S57(2), S57(10)))
+    S57(1), S57(2);
+    if (S57(10))
     {
         assert(dtor_cnt == 3);
         printf("ifbody\n");
@@ -1628,7 +1633,8 @@ void test57()
 
     printf("----\n");
     dtor_cnt = 0;
-    if ((f(1), f(2), f(10)))
+    f(1), f(2);
+    if (f(10))
     {
         assert(dtor_cnt == 3);
         printf("ifbody\n");
@@ -4431,7 +4437,8 @@ struct S64
 
 S64 foo64()
 {
-    return S64((X64(), 1));
+    X64();
+    return S64(1);
 }
 
 void test64()

test/runnable/test16115.d

@@ -25,7 +25,7 @@ auto call()
     else // assert error
     {
         //return n = tagx, null;
-        return n = Test.tag, null;
+        return n = Test.tag;
         //return n = Test.tag;
     }
 }

test/runnable/test22.d

@@ -201,7 +201,9 @@ class B9
     {
         A9 test1 = new A9(1, 2, 3);
         A9 test2 = new A9(1, 2, 3, 4);
-        int[3] arg; A9 test3 = new A9((arg[0]=1, arg[1]=2, arg[2]=3, arg));
+        int[3] arg;
+        arg[0]=1, arg[1]=2, arg[2]=3;
+        A9 test3 = new A9(arg);
     }
 }