dlang · RazvanN7 · Jul 29, 2019 · Jul 26, 2019
diff --git a/src/dmd/expression.d b/src/dmd/expression.d
@@ -5197,19 +5197,6 @@ extern (C++) final class CastExp : UnaExp
         return to ? new CastExp(loc, e1.syntaxCopy(), to.syntaxCopy()) : new CastExp(loc, e1.syntaxCopy(), mod);
     }
 
-    override bool isLvalue()
-    {
-        //printf("e1.type = %s, to.type = %s\n", e1.type.toChars(), to.toChars());
-        return e1.isLvalue() && e1.type.mutableOf().unSharedOf().equals(to.mutableOf().unSharedOf());
-    }
-
-    override Expression toLvalue(Scope* sc, Expression e)
-    {
-        if (isLvalue())
-            return this;
-        return Expression.toLvalue(sc, e);
-    }
-
     override Expression addDtorHook(Scope* sc)
     {
         if (to.toBasetype().ty == Tvoid)        // look past the cast(void)

diff --git a/src/dmd/expressionsem.d b/src/dmd/expressionsem.d
@@ -8748,17 +8748,15 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
             // Try to do a decent error message with the expression
             // before it got constant folded
 
-            // https://issues.dlang.org/show_bug.cgi?id=19754
-            // first see if the unoptimized expression is modifiable
+            if (e1x.op != TOK.variable)
+                e1x = e1x.optimize(WANTvalue);
+
             if (exp.op == TOK.assign)
                 e1x = e1x.modifiableLvalue(sc, e1old);
 
             if (checkIfIsStructLiteralDotExpr(e1x))
                 return setError();
 
-            if (e1x.op != TOK.variable)
-                e1x = e1x.optimize(WANTvalue);
-
             if (e1x.op == TOK.error)
             {
                 result = e1x;

diff --git a/src/dmd/semantic3.d b/src/dmd/semantic3.d
@@ -841,13 +841,7 @@ private extern(C++) final class Semantic3Visitor : Visitor
                         const hasCopyCtor = exp.type.ty == Tstruct && (cast(TypeStruct)exp.type).sym.hasCopyCtor;
                         // if a copy constructor is present, the return type conversion will be handled by it
                         if (!hasCopyCtor)
-                        {
-                            if (f.isref && !MODimplicitConv(exp.type.mod, tret.mod) && !tret.isTypeSArray())
-                                error(exp.loc, "expression `%s` of type `%s` is not implicitly convertible to return type `ref %s`",
-                                      exp.toChars(), exp.type.toChars(), tret.toChars());
-                            else
-                                exp = exp.implicitCastTo(sc2, tret);
-                        }
+                            exp = exp.implicitCastTo(sc2, tret);
 
                         if (f.isref)
                         {

diff --git a/src/dmd/typesem.d b/src/dmd/typesem.d
@@ -1377,13 +1377,6 @@ extern(C++) Type typeSemantic(Type t, Loc loc, Scope* sc)
                         e = new AddrExp(e.loc, e);
                         e = e.expressionSemantic(argsc);
                     }
-                    if (isRefOrOut && (!isAuto || e.isLvalue())
-                        && !MODimplicitConv(e.type.mod, fparam.type.mod))
-                    {
-                        const(char)* errTxt = fparam.storageClass & STC.ref_ ? "ref" : "out";
-                        .error(e.loc, "expression `%s` of type `%s` is not implicitly convertible to type `%s %s` of parameter `%s`",
-                              e.toChars(), e.type.toChars(), errTxt, fparam.type.toChars(), fparam.toChars());
-                    }
                     e = e.implicitCastTo(argsc, fparam.type);
 
                     // default arg must be an lvalue

diff --git a/test/compilable/test19754.d b/test/compilable/test19754.d
diff --git a/test/fail_compilation/b20011.d b/test/fail_compilation/b20011.d
@@ -1,8 +1,8 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/b20011.d(22): Error: cannot modify constant expression `S1(cast(ubyte)0u).member`
-fail_compilation/b20011.d(25): Error: cannot modify constant expression `S2(null).member`
+fail_compilation/b20011.d(22): Error: cannot modify constant `S1(cast(ubyte)0u).member`
+fail_compilation/b20011.d(24): Error: `S2(null).member` is not an lvalue and cannot be modified
 fail_compilation/b20011.d(26): Error: cannot modify constant expression `S2(null).member`
 fail_compilation/b20011.d(27): Error: cannot modify constant expression `S2(null).member`
 fail_compilation/b20011.d(30): Error: cannot modify constant expression `U1(cast(ubyte)0u, ).m2`

diff --git a/test/fail_compilation/diag4596.d b/test/fail_compilation/diag4596.d
@@ -1,12 +1,10 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/diag4596.d(17): Error: `this` is not an lvalue and cannot be modified
-fail_compilation/diag4596.d(18): Error: `this` is not an lvalue and cannot be modified
-fail_compilation/diag4596.d(18): Error: `this` is not an lvalue and cannot be modified
-fail_compilation/diag4596.d(20): Error: `super` is not an lvalue and cannot be modified
-fail_compilation/diag4596.d(21): Error: `super` is not an lvalue and cannot be modified
-fail_compilation/diag4596.d(21): Error: `super` is not an lvalue and cannot be modified
+fail_compilation/diag4596.d(15): Error: `this` is not an lvalue and cannot be modified
+fail_compilation/diag4596.d(16): Error: `1 ? this : this` is not an lvalue and cannot be modified
+fail_compilation/diag4596.d(18): Error: `super` is not an lvalue and cannot be modified
+fail_compilation/diag4596.d(19): Error: `1 ? super : super` is not an lvalue and cannot be modified
 ---
 */
 

diff --git a/test/fail_compilation/fail106.d b/test/fail_compilation/fail106.d
@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/fail106.d(12): Error: cannot modify `immutable` expression `"ABC"[2]`
+fail_compilation/fail106.d(12): Error: cannot modify `immutable` expression `'C'`
 ---
 */
 

diff --git a/test/fail_compilation/fail17491.d b/test/fail_compilation/fail17491.d
@@ -1,11 +1,13 @@
 /* TEST_OUTPUT:
 ---
-fail_compilation/fail17491.d(20): Error: `(S17491).init` is not an lvalue and cannot be modified
-fail_compilation/fail17491.d(21): Error: `S17491(0)` is not an lvalue and cannot be modified
-fail_compilation/fail17491.d(23): Error: cannot modify constant expression `S17491(0).field`
-fail_compilation/fail17491.d(29): Error: `S17491(0)` is not an lvalue and cannot be modified
-fail_compilation/fail17491.d(30): Error: `S17491(0)` is not an lvalue and cannot be modified
-fail_compilation/fail17491.d(32): Error: cannot modify constant expression `S17491(0).field`
+fail_compilation/fail17491.d(22): Error: `(S17491).init` is not an lvalue and cannot be modified
+fail_compilation/fail17491.d(23): Error: `S17491(0)` is not an lvalue and cannot be modified
+fail_compilation/fail17491.d(25): Error: cannot modify constant `S17491(0).field`
+fail_compilation/fail17491.d(26): Error: cannot modify constant `*&S17491(0).field`
+fail_compilation/fail17491.d(31): Error: `S17491(0)` is not an lvalue and cannot be modified
+fail_compilation/fail17491.d(32): Error: `S17491(0)` is not an lvalue and cannot be modified
+fail_compilation/fail17491.d(34): Error: cannot modify constant `S17491(0).field`
+fail_compilation/fail17491.d(35): Error: cannot modify constant `*&S17491(0).field`
 ---
 */
 // https://issues.dlang.org/show_bug.cgi?id=17491

diff --git a/test/fail_compilation/fail351.d b/test/fail_compilation/fail351.d
@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/fail351.d(14): Error: expression `this.num[index]` of type `immutable(uint)` is not implicitly convertible to return type `ref uint`
+fail_compilation/fail351.d(14): Error: `cast(uint)this.num[index]` is not an lvalue and cannot be modified
 ---
 */
 

diff --git a/test/fail_compilation/fail9891.d b/test/fail_compilation/fail9891.d
@@ -1,8 +1,8 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/fail9891.d(13): Error: expression `i` of type `immutable(int)` is not implicitly convertible to type `ref int` of parameter `n`
-fail_compilation/fail9891.d(18): Error: expression `i` of type `immutable(int)` is not implicitly convertible to type `out int` of parameter `n`
+fail_compilation/fail9891.d(13): Error: `cast(int)i` is not an lvalue and cannot be modified
+fail_compilation/fail9891.d(18): Error: `cast(int)i` is not an lvalue and cannot be modified
 fail_compilation/fail9891.d(23): Error: `prop()` is not an lvalue and cannot be modified
 ---
 */

diff --git a/test/compilable/test14929.d → test/fail_compilation/ice14929.d b/test/compilable/test14929.d → test/fail_compilation/ice14929.d
@@ -1,3 +1,14 @@
+/*
+TEST_OUTPUT:
+---
+fail_compilation/ice14929.d(45): Error: `cast(Node)(*this.current).items[this.index]` is not an lvalue and cannot be modified
+fail_compilation/ice14929.d(88): Error: template instance `ice14929.HashMap!(ulong, int).HashMap.opBinaryRight!"in"` error instantiating
+fail_compilation/ice14929.d(92):        instantiated from here: `HashmapComponentStorage!int`
+fail_compilation/ice14929.d(92): Error: template instance `ice14929.isComponentStorage!(HashmapComponentStorage!int, int)` error instantiating
+fail_compilation/ice14929.d(92):        while evaluating: `static assert(isComponentStorage!(HashmapComponentStorage!int, int))`
+---
+*/
+
 struct HashMap(K, V)
 {
     V* opBinaryRight(string op)(K key) const if (op == "in")

diff --git a/test/fail_compilation/test12385.d b/test/fail_compilation/test12385.d
@@ -1,7 +1,7 @@
 /*
 TEST_OUTPUT:
 ---
-fail_compilation/test12385.d(29): Error: cannot modify `immutable` expression `unbundled.x`
+fail_compilation/test12385.d(29): Error: cannot modify `immutable` expression `BundledState("bla", 3).x`
 ---
 */