diff --git a/changelog/dmd.error-messages.dd b/changelog/dmd.error-messages.dd
index ddb3f6341f0..2d3ce440b10 100644
--- a/changelog/dmd.error-messages.dd
+++ b/changelog/dmd.error-messages.dd
@@ -53,7 +53,7 @@ app.d(1):        perhaps define `auto opSlice(int lower, string upper) {}` for `
 */
 ---
 
-When overloading binary operators, and `opBinary` or `opBinaryRight` is missing or doesn't match,
+When overloading binary operators, and `opBinary`, `opBinaryRight` or `opOpAssign` is missing / fails to instantiate,
 the error message now points out the problem:
 
 ---
diff --git a/compiler/src/dmd/expressionsem.d b/compiler/src/dmd/expressionsem.d
index 3b9743e2927..7e9c95b9a9f 100644
--- a/compiler/src/dmd/expressionsem.d
+++ b/compiler/src/dmd/expressionsem.d
@@ -3819,6 +3819,9 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
     // See tryAliasThisSemantic
     Type[2] aliasThisStop;
 
+    // (Optional) the expression this was lowered from, for better error messages
+    Expression parent;
+
     this(Scope* sc) scope @safe
     {
         this.sc = sc;
@@ -7583,15 +7586,8 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
         exp.e1 = exp.e1.optimize(WANTvalue, /*keepLvalue*/ true);
         exp.type = exp.e1.type;
 
-        if (auto ad = isAggregate(exp.e1.type))
-        {
-            if (const s = search_function(ad, Id.opOpAssign))
-            {
-                error(exp.loc, "none of the `opOpAssign` overloads of `%s` are callable for `%s` of type `%s`", ad.toChars(), exp.e1.toChars(), exp.e1.type.toChars());
-                return setError();
-            }
-        }
-        if (exp.e1.checkScalar() ||
+        if (exp.suggestOpOpAssign(sc, parent) ||
+            exp.e1.checkScalar() ||
             exp.e1.checkReadModifyWrite(exp.op, exp.e2) ||
             exp.e1.checkSharedAccess(sc))
             return setError();
@@ -10233,7 +10229,7 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             e = new AddAssignExp(exp.loc, exp.e1, IntegerExp.literal!1);
         else
             e = new MinAssignExp(exp.loc, exp.e1, IntegerExp.literal!1);
-        result = e.expressionSemantic(sc);
+        result = e.expressionSemanticWithParent(sc, exp);
     }
 
     /*
@@ -11745,7 +11741,8 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             return;
         }
 
-        if (exp.e1.checkReadModifyWrite(exp.op, exp.e2))
+        if (exp.suggestOpOpAssign(sc, parent) ||
+            exp.e1.checkReadModifyWrite(exp.op, exp.e2))
             return setError();
 
         assert(exp.e1.type && exp.e2.type);
@@ -11824,6 +11821,9 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             return;
         }
 
+        if (exp.suggestOpOpAssign(sc, parent))
+            return setError();
+
         if (SliceExp se = exp.e1.isSliceExp())
         {
             if (se.e1.type.toBasetype().ty == Tsarray)
@@ -13877,6 +13877,20 @@ private Expression expressionSemantic(Expression e, Scope* sc, Type[2] aliasThis
     return v.result;
 }
 
+// ditto, but with `parent` parameter that represents the expression before rewriting.
+// This way, when lowering an expression (e.g. i++ to i+=1), error messages can still
+// refer to the original expression.
+private Expression expressionSemanticWithParent(Expression e, Scope* sc, Expression parent)
+{
+    if (e.expressionSemanticDone)
+        return e;
+
+    scope v = new ExpressionSemanticVisitor(sc);
+    v.parent = parent;
+    e.accept(v);
+    return v.result;
+}
+
 private Expression dotIdSemanticPropX(DotIdExp exp, Scope* sc)
 {
     //printf("dotIdSemanticPropX() %s\n", toChars(exp));
diff --git a/compiler/src/dmd/opover.d b/compiler/src/dmd/opover.d
index 01dffccdfcf..1b53a442c5b 100644
--- a/compiler/src/dmd/opover.d
+++ b/compiler/src/dmd/opover.d
@@ -94,58 +94,40 @@ private bool hasOpBinary(EXP op) pure @safe
     }
 }
 
+/**
+ * Remove the = from op=, e.g. += becomes +
+ *
+ * Params:
+ *     op = tag for a binary assign operator
+ * Returns: the corresponding binary operator, or `op` if it wasn't an assign operator
+*/
+private EXP stripAssignOp(EXP op)
+{
+    switch (op)
+    {
+    case EXP.addAssign: return EXP.add;
+    case EXP.minAssign: return EXP.min;
+    case EXP.mulAssign: return EXP.mul;
+    case EXP.divAssign: return EXP.div;
+    case EXP.modAssign: return EXP.mod;
+    case EXP.andAssign: return EXP.and;
+    case EXP.orAssign: return EXP.or;
+    case EXP.xorAssign: return EXP.xor;
+    case EXP.leftShiftAssign: return EXP.leftShift;
+    case EXP.rightShiftAssign: return EXP.rightShift;
+    case EXP.unsignedRightShiftAssign: return EXP.unsignedRightShift;
+    case EXP.concatenateAssign: return EXP.concatenate;
+    case EXP.powAssign: return EXP.pow;
+    default: return op;
+    }
+}
+
 /*******************************************
  * Helper function to turn operator into template argument list
  */
 Objects* opToArg(Scope* sc, EXP op)
 {
-    /* Remove the = from op=
-     */
-    switch (op)
-    {
-    case EXP.addAssign:
-        op = EXP.add;
-        break;
-    case EXP.minAssign:
-        op = EXP.min;
-        break;
-    case EXP.mulAssign:
-        op = EXP.mul;
-        break;
-    case EXP.divAssign:
-        op = EXP.div;
-        break;
-    case EXP.modAssign:
-        op = EXP.mod;
-        break;
-    case EXP.andAssign:
-        op = EXP.and;
-        break;
-    case EXP.orAssign:
-        op = EXP.or;
-        break;
-    case EXP.xorAssign:
-        op = EXP.xor;
-        break;
-    case EXP.leftShiftAssign:
-        op = EXP.leftShift;
-        break;
-    case EXP.rightShiftAssign:
-        op = EXP.rightShift;
-        break;
-    case EXP.unsignedRightShiftAssign:
-        op = EXP.unsignedRightShift;
-        break;
-    case EXP.concatenateAssign:
-        op = EXP.concatenate;
-        break;
-    case EXP.powAssign:
-        op = EXP.pow;
-        break;
-    default:
-        break;
-    }
-    Expression e = new StringExp(Loc.initial, EXPtoString(op));
+    Expression e = new StringExp(Loc.initial, EXPtoString(stripAssignOp(op)));
     e = e.expressionSemantic(sc);
     auto tiargs = new Objects();
     tiargs.push(e);
@@ -640,6 +622,45 @@ bool suggestBinaryOverloads(BinExp e, Scope* sc)
     return false;
 }
 
+/**
+ * If applicable, print an error relating to implementing / fixing `opOpAssign` or `opUnary` functions.
+ * Params:
+ *   exp = binary operation
+ *   sc = scope to try `opOpAssign!""` semantic in for error messages
+ *   parent = if `exp` was lowered from this `PreExp` or `PostExp`, mention `opUnary` as well
+ * Returns: `true` when an error related to `opOpAssign` was printed
+ */
+bool suggestOpOpAssign(BinAssignExp exp, Scope* sc, Expression parent)
+{
+    auto ad = isAggregate(exp.e1.type);
+    if (!ad)
+        return false;
+
+    if (parent && (parent.isPreExp() || parent.isPostExp()))
+    {
+        error(exp.loc, "operator `%s` not supported for `%s` of type `%s`", EXPtoString(parent.op).ptr, exp.e1.toChars(), ad.toChars());
+        errorSupplemental(ad.loc,
+            "perhaps implement `auto opUnary(string op : \"%s\")() {}`"~
+            " or `auto opOpAssign(string op : \"%s\")(int) {}`",
+            EXPtoString(stripAssignOp(parent.op)).ptr,
+            EXPtoString(stripAssignOp(exp.op)).ptr
+            );
+        return true;
+    }
+
+    if (const s = search_function(ad, Id.opOpAssign))
+    {
+        dotTemplateCall(exp.e1, Id.opOpAssign, opToArg(sc, exp.op), exp.e2).expressionSemantic(sc);
+    }
+    else
+    {
+        error(exp.loc, "operator `%s` not supported for `%s` of type `%s`", EXPtoString(exp.op).ptr, exp.e1.toChars(), ad.toChars());
+        errorSupplemental(ad.loc, "perhaps implement `auto opOpAssign(string op : \"%s\")(%s) {}`",
+            EXPtoString(stripAssignOp(exp.op)).ptr, exp.e2.type.toChars());
+    }
+    return true;
+}
+
 // Helper to construct e.id!tiargs(args), e.g. `lhs.opBinary!"+"(rhs)`
 private Expression dotTemplateCall(Expression e, Identifier id, Objects* tiargs, Expression[] args...)
 {
diff --git a/compiler/test/fail_compilation/dep_d1_ops.d b/compiler/test/fail_compilation/dep_d1_ops.d
index ec1a0f1c857..8d800b42a65 100644
--- a/compiler/test/fail_compilation/dep_d1_ops.d
+++ b/compiler/test/fail_compilation/dep_d1_ops.d
@@ -2,135 +2,163 @@
 REQUIRED_ARGS:
 TEST_OUTPUT:
 ---
-fail_compilation/dep_d1_ops.d(244): Error: operator `+` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "+")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(245): Error: operator `+` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "+")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(246): Error: operator `-` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "-")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(247): Error: operator `-` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "-")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(248): Error: operator `*` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "*")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(249): Error: operator `*` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "*")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(250): Error: operator `/` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "/")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(251): Error: operator `/` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "/")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(252): Error: operator `%` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "%")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(253): Error: operator `%` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "%")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(255): Error: operator `&` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "&")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(256): Error: operator `|` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "|")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(257): Error: operator `^` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "^")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(259): Error: operator `<<` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "<<")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(260): Error: operator `<<` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "<<")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(261): Error: operator `>>` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : ">>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(262): Error: operator `>>` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : ">>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(263): Error: operator `>>>` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : ">>>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(264): Error: operator `>>>` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : ">>>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(266): Error: operator `~` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "~")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(267): Error: operator `~` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "~")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(269): Error: operator `+` is not defined for `s` of type `S`
-fail_compilation/dep_d1_ops.d(270): Error: operator `-` is not defined for `s` of type `S`
-fail_compilation/dep_d1_ops.d(271): Error: `s` is not of integral type, it is a `S`
-fail_compilation/dep_d1_ops.d(272): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(273): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(274): Error: can only `*` a pointer, not a `S`
-fail_compilation/dep_d1_ops.d(276): Error: operator `in` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinary(string op : "in")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(277): Error: operator `in` is not defined for type `S`
-fail_compilation/dep_d1_ops.d(137):        perhaps overload the operator with `auto opBinaryRight(string op : "in")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(279): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(280): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(281): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(282): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(283): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(284): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(285): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(286): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(287): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(288): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(289): Error: `s` is not a scalar, it is a `S`
-fail_compilation/dep_d1_ops.d(290): Error: cannot append type `int` to type `S`
-fail_compilation/dep_d1_ops.d(294): Error: operator `+` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "+")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(295): Error: operator `+` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "+")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(296): Error: operator `-` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "-")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(297): Error: operator `-` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "-")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(298): Error: operator `*` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "*")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(299): Error: operator `*` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "*")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(300): Error: operator `/` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "/")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(301): Error: operator `/` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "/")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(302): Error: operator `%` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "%")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(303): Error: operator `%` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "%")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(305): Error: operator `&` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "&")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(306): Error: operator `|` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "|")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(307): Error: operator `^` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "^")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(309): Error: operator `<<` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "<<")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(310): Error: operator `<<` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "<<")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(311): Error: operator `>>` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : ">>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(312): Error: operator `>>` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : ">>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(313): Error: operator `>>>` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : ">>>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(314): Error: operator `>>>` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : ">>>")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(316): Error: operator `~` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "~")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(317): Error: operator `~` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "~")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(319): Error: operator `+` is not defined for `c` of type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(320): Error: operator `-` is not defined for `c` of type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(321): Error: `c` is not of integral type, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(322): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(323): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(324): Error: can only `*` a pointer, not a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(326): Error: operator `in` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinary(string op : "in")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(327): Error: operator `in` is not defined for type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(188):        perhaps overload the operator with `auto opBinaryRight(string op : "in")(int rhs) {}`
-fail_compilation/dep_d1_ops.d(329): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(330): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(331): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(332): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(333): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(334): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(335): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(336): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(337): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(338): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(339): Error: `c` is not a scalar, it is a `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(340): Error: cannot append type `int` to type `dep_d1_ops.C`
-fail_compilation/dep_d1_ops.d(349): Error: `nd` is not of integral type, it is a `dep_d1_ops.NoDeprecation`
+fail_compilation/dep_d1_ops.d(272): Error: operator `+` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "+")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(273): Error: operator `+` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "+")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(274): Error: operator `-` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "-")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(275): Error: operator `-` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "-")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(276): Error: operator `*` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "*")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(277): Error: operator `*` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "*")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(278): Error: operator `/` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "/")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(279): Error: operator `/` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "/")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(280): Error: operator `%` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "%")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(281): Error: operator `%` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "%")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(283): Error: operator `&` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "&")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(284): Error: operator `|` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "|")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(285): Error: operator `^` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "^")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(287): Error: operator `<<` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "<<")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(288): Error: operator `<<` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "<<")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(289): Error: operator `>>` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : ">>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(290): Error: operator `>>` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : ">>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(291): Error: operator `>>>` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : ">>>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(292): Error: operator `>>>` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : ">>>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(294): Error: operator `~` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "~")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(295): Error: operator `~` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "~")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(297): Error: operator `+` is not defined for `s` of type `S`
+fail_compilation/dep_d1_ops.d(298): Error: operator `-` is not defined for `s` of type `S`
+fail_compilation/dep_d1_ops.d(299): Error: `s` is not of integral type, it is a `S`
+fail_compilation/dep_d1_ops.d(300): Error: operator `++` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opUnary(string op : "++")() {}` or `auto opOpAssign(string op : "+")(int) {}`
+fail_compilation/dep_d1_ops.d(301): Error: operator `--` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opUnary(string op : "--")() {}` or `auto opOpAssign(string op : "-")(int) {}`
+fail_compilation/dep_d1_ops.d(302): Error: can only `*` a pointer, not a `S`
+fail_compilation/dep_d1_ops.d(304): Error: operator `in` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinary(string op : "in")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(305): Error: operator `in` is not defined for type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps overload the operator with `auto opBinaryRight(string op : "in")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(307): Error: operator `+=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "+")(int) {}`
+fail_compilation/dep_d1_ops.d(308): Error: operator `-=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "-")(int) {}`
+fail_compilation/dep_d1_ops.d(309): Error: operator `*=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "*")(int) {}`
+fail_compilation/dep_d1_ops.d(310): Error: operator `/=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "/")(int) {}`
+fail_compilation/dep_d1_ops.d(311): Error: operator `%=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "%")(int) {}`
+fail_compilation/dep_d1_ops.d(312): Error: operator `&=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "&")(int) {}`
+fail_compilation/dep_d1_ops.d(313): Error: operator `|=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "|")(int) {}`
+fail_compilation/dep_d1_ops.d(314): Error: operator `^=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "^")(int) {}`
+fail_compilation/dep_d1_ops.d(315): Error: operator `<<=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "<<")(int) {}`
+fail_compilation/dep_d1_ops.d(316): Error: operator `>>=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : ">>")(int) {}`
+fail_compilation/dep_d1_ops.d(317): Error: operator `>>>=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : ">>>")(int) {}`
+fail_compilation/dep_d1_ops.d(318): Error: operator `~=` not supported for `s` of type `S`
+fail_compilation/dep_d1_ops.d(165):        perhaps implement `auto opOpAssign(string op : "~")(int) {}`
+fail_compilation/dep_d1_ops.d(322): Error: operator `+` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "+")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(323): Error: operator `+` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "+")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(324): Error: operator `-` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "-")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(325): Error: operator `-` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "-")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(326): Error: operator `*` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "*")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(327): Error: operator `*` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "*")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(328): Error: operator `/` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "/")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(329): Error: operator `/` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "/")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(330): Error: operator `%` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "%")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(331): Error: operator `%` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "%")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(333): Error: operator `&` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "&")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(334): Error: operator `|` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "|")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(335): Error: operator `^` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "^")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(337): Error: operator `<<` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "<<")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(338): Error: operator `<<` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "<<")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(339): Error: operator `>>` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : ">>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(340): Error: operator `>>` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : ">>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(341): Error: operator `>>>` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : ">>>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(342): Error: operator `>>>` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : ">>>")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(344): Error: operator `~` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "~")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(345): Error: operator `~` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "~")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(347): Error: operator `+` is not defined for `c` of type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(348): Error: operator `-` is not defined for `c` of type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(349): Error: `c` is not of integral type, it is a `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(350): Error: operator `++` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opUnary(string op : "++")() {}` or `auto opOpAssign(string op : "+")(int) {}`
+fail_compilation/dep_d1_ops.d(351): Error: operator `--` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opUnary(string op : "--")() {}` or `auto opOpAssign(string op : "-")(int) {}`
+fail_compilation/dep_d1_ops.d(352): Error: can only `*` a pointer, not a `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(354): Error: operator `in` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinary(string op : "in")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(355): Error: operator `in` is not defined for type `dep_d1_ops.C`
+fail_compilation/dep_d1_ops.d(216):        perhaps overload the operator with `auto opBinaryRight(string op : "in")(int rhs) {}`
+fail_compilation/dep_d1_ops.d(357): Error: operator `+=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "+")(int) {}`
+fail_compilation/dep_d1_ops.d(358): Error: operator `-=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "-")(int) {}`
+fail_compilation/dep_d1_ops.d(359): Error: operator `*=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "*")(int) {}`
+fail_compilation/dep_d1_ops.d(360): Error: operator `/=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "/")(int) {}`
+fail_compilation/dep_d1_ops.d(361): Error: operator `%=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "%")(int) {}`
+fail_compilation/dep_d1_ops.d(362): Error: operator `&=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "&")(int) {}`
+fail_compilation/dep_d1_ops.d(363): Error: operator `|=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "|")(int) {}`
+fail_compilation/dep_d1_ops.d(364): Error: operator `^=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "^")(int) {}`
+fail_compilation/dep_d1_ops.d(365): Error: operator `<<=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "<<")(int) {}`
+fail_compilation/dep_d1_ops.d(366): Error: operator `>>=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : ">>")(int) {}`
+fail_compilation/dep_d1_ops.d(367): Error: operator `>>>=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : ">>>")(int) {}`
+fail_compilation/dep_d1_ops.d(368): Error: operator `~=` not supported for `c` of type `C`
+fail_compilation/dep_d1_ops.d(216):        perhaps implement `auto opOpAssign(string op : "~")(int) {}`
+fail_compilation/dep_d1_ops.d(377): Error: `nd` is not of integral type, it is a `dep_d1_ops.NoDeprecation`
 ---
 */
 
diff --git a/compiler/test/fail_compilation/diag13320.d b/compiler/test/fail_compilation/diag13320.d
index 2808606bdca..40b99ab39d0 100644
--- a/compiler/test/fail_compilation/diag13320.d
+++ b/compiler/test/fail_compilation/diag13320.d
@@ -1,7 +1,8 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/diag13320.d(13): Error: `f` is not a scalar, it is a `Foo`
+fail_compilation/diag13320.d(14): Error: operator `++` not supported for `f` of type `Foo`
+fail_compilation/diag13320.d(9):        perhaps implement `auto opUnary(string op : "++")() {}` or `auto opOpAssign(string op : "+")(int) {}`
 ---
 */
 
diff --git a/compiler/test/fail_compilation/fail18985.d b/compiler/test/fail_compilation/fail18985.d
index 830a6792ad2..f2899bdb337 100644
--- a/compiler/test/fail_compilation/fail18985.d
+++ b/compiler/test/fail_compilation/fail18985.d
@@ -1,15 +1,19 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/fail18985.d(16): Error: `foo` is not a scalar, it is a `object.Object`
-fail_compilation/fail18985.d(17): Error: `bar` is not a scalar, it is a `shared(Object)`
+fail_compilation/fail18985.d(20): Error: operator `+=` not supported for `foo` of type `C`
+fail_compilation/fail18985.d(13):        perhaps implement `auto opOpAssign(string op : "+")(int) {}`
+fail_compilation/fail18985.d(21): Error: operator `+=` not supported for `bar` of type `C`
+fail_compilation/fail18985.d(13):        perhaps implement `auto opOpAssign(string op : "+")(int) {}`
 ---
 */
 
 // https://issues.dlang.org/show_bug.cgi?id=18985
 
-Object foo;
-shared Object bar;
+class C {}
+
+C foo;
+shared C bar;
 
 void main()
 {
diff --git a/compiler/test/fail_compilation/fail3672.d b/compiler/test/fail_compilation/fail3672.d
index 2f9bdf742b7..0062798f312 100644
--- a/compiler/test/fail_compilation/fail3672.d
+++ b/compiler/test/fail_compilation/fail3672.d
@@ -1,9 +1,10 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/fail3672.d(28): Error: read-modify-write operations are not allowed for `shared` variables
-fail_compilation/fail3672.d(28):        Use `core.atomic.atomicOp!"+="(*p, 1)` instead
-fail_compilation/fail3672.d(32): Error: none of the `opOpAssign` overloads of `SF` are callable for `*sfp` of type `shared(SF)`
+fail_compilation/fail3672.d(29): Error: read-modify-write operations are not allowed for `shared` variables
+fail_compilation/fail3672.d(29):        Use `core.atomic.atomicOp!"+="(*p, 1)` instead
+fail_compilation/fail3672.d(33): Error: template `opOpAssign` is not callable using argument types `!("+")(int) shared`
+fail_compilation/fail3672.d(13):        Candidate is: `opOpAssign(string op, T)(T rhs)`
 ---
 */