fix Issue 12985 - Better error message for not supported array operation

src/arrayop.c

@@ -154,11 +154,14 @@ bool isNonAssignmentArrayOp(Expression *e)
     return false;
 }
 
-bool checkNonAssignmentArrayOp(Expression *e)
+bool checkNonAssignmentArrayOp(Expression *e, bool suggestion)
 {
     if (isNonAssignmentArrayOp(e))
     {
-        e->error("array operation %s without assignment not implemented", e->toChars());
+        const char *s = "";
+        if (suggestion)
+            s = " (did you forget a [] ?)";
+        e->error("array operation %s without destination memory not allowed%s", e->toChars(), s);
         return true;
     }
     return false;

src/expression.c

@@ -11514,7 +11514,7 @@ Expression *AssignExp::semantic(Scope *sc)
 
         // Drop invalid array operations in e2
         //  d = a[] + b[], d = (a[] + b[])[0..2], etc
-        if (checkNonAssignmentArrayOp(e2))
+        if (checkNonAssignmentArrayOp(e2, !ismemset && op == TOKassign))
             return new ErrorExp();
 
         // Remains valid array assignments

src/expression.h

@@ -80,7 +80,7 @@ int isConst(Expression *e);
 Expression *toDelegate(Expression *e, Scope *sc);
 AggregateDeclaration *isAggregate(Type *t);
 IntRange getIntRange(Expression *e);
-bool checkNonAssignmentArrayOp(Expression *e);
+bool checkNonAssignmentArrayOp(Expression *e, bool suggestion = false);
 bool isUnaArrayOp(TOK op);
 bool isBinArrayOp(TOK op);
 bool isBinAssignArrayOp(TOK op);

test/fail_compilation/fail9459.d

@@ -3,17 +3,17 @@ REQUIRED_ARGS: -o-
 PERMUTE_ARGS:
 TEST_OUTPUT:
 ---
-fail_compilation/fail9459.d(32): Error: array operation -a[] without assignment not implemented
-fail_compilation/fail9459.d(33): Error: array operation ~a[] without assignment not implemented
-fail_compilation/fail9459.d(35): Error: array operation a[] + a[] without assignment not implemented
-fail_compilation/fail9459.d(36): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/fail9459.d(37): Error: array operation a[] * a[] without assignment not implemented
-fail_compilation/fail9459.d(38): Error: array operation a[] / a[] without assignment not implemented
-fail_compilation/fail9459.d(39): Error: array operation a[] % a[] without assignment not implemented
-fail_compilation/fail9459.d(40): Error: array operation a[] ^ a[] without assignment not implemented
-fail_compilation/fail9459.d(41): Error: array operation a[] & a[] without assignment not implemented
-fail_compilation/fail9459.d(42): Error: array operation a[] | a[] without assignment not implemented
-fail_compilation/fail9459.d(43): Error: array operation a[] ^^ a[] without assignment not implemented
+fail_compilation/fail9459.d(32): Error: array operation -a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(33): Error: array operation ~a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(35): Error: array operation a[] + a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(36): Error: array operation a[] - a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(37): Error: array operation a[] * a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(38): Error: array operation a[] / a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(39): Error: array operation a[] % a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(40): Error: array operation a[] ^ a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(41): Error: array operation a[] & a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(42): Error: array operation a[] | a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/fail9459.d(43): Error: array operation a[] ^^ a[] without destination memory not allowed (did you forget a [] ?)
 fail_compilation/fail9459.d(45): Error: invalid array operation a += a[] (did you forget a [] ?)
 fail_compilation/fail9459.d(46): Error: invalid array operation a -= a[] (did you forget a [] ?)
 fail_compilation/fail9459.d(47): Error: invalid array operation a *= a[] (did you forget a [] ?)

test/fail_compilation/ice12179.d

@@ -1,19 +1,19 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice12179.d(25): Error: array operation a[] + a[] without assignment not implemented
-fail_compilation/ice12179.d(26): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/ice12179.d(27): Error: array operation a[] * a[] without assignment not implemented
-fail_compilation/ice12179.d(28): Error: array operation a[] / a[] without assignment not implemented
-fail_compilation/ice12179.d(29): Error: array operation a[] % a[] without assignment not implemented
-fail_compilation/ice12179.d(30): Error: array operation a[] ^ a[] without assignment not implemented
-fail_compilation/ice12179.d(31): Error: array operation a[] & a[] without assignment not implemented
-fail_compilation/ice12179.d(32): Error: array operation a[] | a[] without assignment not implemented
-fail_compilation/ice12179.d(33): Error: array operation a[] ^^ 10 without assignment not implemented
-fail_compilation/ice12179.d(34): Error: array operation -a[] without assignment not implemented
-fail_compilation/ice12179.d(35): Error: array operation ~a[] without assignment not implemented
-fail_compilation/ice12179.d(40): Error: array operation [1] + a[] without assignment not implemented
-fail_compilation/ice12179.d(41): Error: array operation [1] + a[] without assignment not implemented
+fail_compilation/ice12179.d(25): Error: array operation a[] + a[] without destination memory not allowed
+fail_compilation/ice12179.d(26): Error: array operation a[] - a[] without destination memory not allowed
+fail_compilation/ice12179.d(27): Error: array operation a[] * a[] without destination memory not allowed
+fail_compilation/ice12179.d(28): Error: array operation a[] / a[] without destination memory not allowed
+fail_compilation/ice12179.d(29): Error: array operation a[] % a[] without destination memory not allowed
+fail_compilation/ice12179.d(30): Error: array operation a[] ^ a[] without destination memory not allowed
+fail_compilation/ice12179.d(31): Error: array operation a[] & a[] without destination memory not allowed
+fail_compilation/ice12179.d(32): Error: array operation a[] | a[] without destination memory not allowed
+fail_compilation/ice12179.d(33): Error: array operation a[] ^^ 10 without destination memory not allowed
+fail_compilation/ice12179.d(34): Error: array operation -a[] without destination memory not allowed
+fail_compilation/ice12179.d(35): Error: array operation ~a[] without destination memory not allowed
+fail_compilation/ice12179.d(40): Error: array operation [1] + a[] without destination memory not allowed
+fail_compilation/ice12179.d(41): Error: array operation [1] + a[] without destination memory not allowed
 ---
 */
 
@@ -45,8 +45,8 @@ void main()
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice12179.d(55): Error: array operation -a[] without assignment not implemented
-fail_compilation/ice12179.d(57): Error: array operation (-a[])[0..4] without assignment not implemented
+fail_compilation/ice12179.d(55): Error: array operation -a[] without destination memory not allowed
+fail_compilation/ice12179.d(57): Error: array operation (-a[])[0..4] without destination memory not allowed
 ---
 */
 float[] f12769(float[] a)
@@ -60,11 +60,11 @@ float[] f12769(float[] a)
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice12179.d(74): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/ice12179.d(76): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/ice12179.d(77): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/ice12179.d(80): Error: array operation a[] - a[] without assignment not implemented
-fail_compilation/ice12179.d(82): Error: array operation a[] - a[] without assignment not implemented
+fail_compilation/ice12179.d(74): Error: array operation a[] - a[] without destination memory not allowed
+fail_compilation/ice12179.d(76): Error: array operation a[] - a[] without destination memory not allowed
+fail_compilation/ice12179.d(77): Error: array operation a[] - a[] without destination memory not allowed
+fail_compilation/ice12179.d(80): Error: array operation a[] - a[] without destination memory not allowed
+fail_compilation/ice12179.d(82): Error: array operation a[] - a[] without destination memory not allowed
 ---
 */
 void test13208()

test/fail_compilation/ice13497.d

@@ -2,10 +2,10 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice13497.d(15): Error: array operation a[] * a[] without assignment not implemented
-fail_compilation/ice13497.d(16): Error: array operation (a[] * a[])[0..1] without assignment not implemented
-fail_compilation/ice13497.d(19): Error: array operation a[] * a[] without assignment not implemented
-fail_compilation/ice13497.d(20): Error: array operation (a[] * a[])[0..1] without assignment not implemented
+fail_compilation/ice13497.d(15): Error: array operation a[] * a[] without destination memory not allowed
+fail_compilation/ice13497.d(16): Error: array operation (a[] * a[])[0..1] without destination memory not allowed
+fail_compilation/ice13497.d(19): Error: array operation a[] * a[] without destination memory not allowed (did you forget a [] ?)
+fail_compilation/ice13497.d(20): Error: array operation (a[] * a[])[0..1] without destination memory not allowed (did you forget a [] ?)
 ---
 */
 
@@ -23,7 +23,7 @@ void test13497()
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice13497.d(34): Error: array operation h * y[] without assignment not implemented
+fail_compilation/ice13497.d(34): Error: array operation h * y[] without destination memory not allowed
 ---
 */
 void test12381()

test/fail_compilation/ice2603.d

@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/ice2603.d(17): Error: array operation [1, 2, 3] - [1, 2, 3] without assignment not implemented
+fail_compilation/ice2603.d(17): Error: array operation [1, 2, 3] - [1, 2, 3] without destination memory not allowed
 fail_compilation/ice2603.d(20): Error: invalid array operation "a" - "b" (did you forget a [] ?)
 ---
 */