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Fix Issue 19754 - cast() sometimes yields lvalue, sometimes yields rvalue #9505

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Merged
dlang-bot merged 1 commit into from
May 24, 2019
Merged

Fix Issue 19754 - cast() sometimes yields lvalue, sometimes yields rvalue #9505

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13 changes: 13 additions & 0 deletions src/dmd/expression.d
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Original file line number Diff line number Diff line change
Expand Up @@ -5158,6 +5158,19 @@ 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)
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8 changes: 5 additions & 3 deletions src/dmd/expressionsem.d
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Expand Up @@ -8515,12 +8515,14 @@ private extern (C++) final class ExpressionSemanticVisitor : Visitor
// Try to do a decent error message with the expression
// before it got constant folded

if (e1x.op != TOK.variable)
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@ghost ghost Jun 30, 2019

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20011 is caused by the displacement of this IfStatement

e1x = e1x.optimize(WANTvalue);

// https://issues.dlang.org/show_bug.cgi?id=19754
// first see if the unoptimized expression is modifiable
if (exp.op == TOK.assign)
e1x = e1x.modifiableLvalue(sc, e1old);

if (e1x.op != TOK.variable)
e1x = e1x.optimize(WANTvalue);

if (e1x.op == TOK.error)
{
result = e1x;
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8 changes: 7 additions & 1 deletion src/dmd/semantic3.d
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Expand Up @@ -827,7 +827,13 @@ 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)
exp = exp.implicitCastTo(sc2, tret);
{
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);
}

if (f.isref)
{
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9 changes: 8 additions & 1 deletion src/dmd/typesem.d
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Expand Up @@ -1343,7 +1343,8 @@ extern(C++) Type typeSemantic(Type t, Loc loc, Scope* sc)
if (fparam.defaultArg)
{
Expression e = fparam.defaultArg;
if (fparam.storageClass & (STC.ref_ | STC.out_))
auto isRefOrOut = fparam.storageClass & (STC.ref_ | STC.out_);
if (isRefOrOut)
{
e = e.expressionSemantic(argsc);
e = resolveProperties(argsc, e);
Expand All @@ -1365,6 +1366,12 @@ extern(C++) Type typeSemantic(Type t, Loc loc, Scope* sc)
e = new AddrExp(e.loc, e);
e = e.expressionSemantic(argsc);
}
if (isRefOrOut && !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
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11 changes: 0 additions & 11 deletions test/fail_compilation/ice14929.d → test/compilable/test14929.d
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@@ -1,14 +1,3 @@
/*
TEST_OUTPUT:
---
fail_compilation/ice14929.d(45): Error: `cast(Node)(*this.current).items[this.index]` is not an lvalue and cannot be modified
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@RazvanN7 RazvanN7 Mar 29, 2019

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this was casting a const(Node) to a Node.

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")
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11 changes: 11 additions & 0 deletions test/compilable/test19754.d
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Original file line number Diff line number Diff line change
@@ -0,0 +1,11 @@
void main()
{
shared int x;
(cast() x) = 5;

const int x1;
(cast() x1) = 5;

immutable int x2;
(cast() x2) = 5;
}
10 changes: 6 additions & 4 deletions test/fail_compilation/diag4596.d
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@@ -1,10 +1,12 @@
/*
TEST_OUTPUT:
---
fail_compilation/diag4596.d(15): Error: `this` is not an lvalue and cannot be modified
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@RazvanN7 RazvanN7 Mar 29, 2019

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The branches of the ?: operator may return different things, e.g. an rvalue and an rvalue; this way the error is printed depending on the branch

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
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
---
*/

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2 changes: 1 addition & 1 deletion test/fail_compilation/fail106.d
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@@ -1,7 +1,7 @@
/*
TEST_OUTPUT:
---
fail_compilation/fail106.d(12): Error: cannot modify `immutable` expression `'C'`
fail_compilation/fail106.d(12): Error: cannot modify `immutable` expression `"ABC"[2]`
---
*/

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12 changes: 4 additions & 8 deletions test/fail_compilation/fail17491.d
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@@ -1,13 +1,9 @@
/* TEST_OUTPUT:
---
fail_compilation/fail17491.d(24): Error: `(S17491).init` is not an lvalue and cannot be modified
fail_compilation/fail17491.d(25): Error: `S17491(0)` is not an lvalue and cannot be modified
fail_compilation/fail17491.d(27): Error: cannot modify constant `S17491(0).field`
fail_compilation/fail17491.d(28): Error: cannot modify constant `*&S17491(0).field`
fail_compilation/fail17491.d(33): Error: `S17491(0)` is not an lvalue and cannot be modified
fail_compilation/fail17491.d(34): Error: `S17491(0)` is not an lvalue and cannot be modified
fail_compilation/fail17491.d(36): Error: cannot modify constant `S17491(0).field`
fail_compilation/fail17491.d(37): Error: cannot modify constant `*&S17491(0).field`
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(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
---
*/

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

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4 changes: 2 additions & 2 deletions test/fail_compilation/fail9891.d
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@@ -1,8 +1,8 @@
/*
TEST_OUTPUT:
---
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(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(23): Error: `prop()` is not an lvalue and cannot be modified
---
*/
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2 changes: 1 addition & 1 deletion test/fail_compilation/test12385.d
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@@ -1,7 +1,7 @@
/*
TEST_OUTPUT:
---
fail_compilation/test12385.d(29): Error: cannot modify `immutable` expression `BundledState("bla", 3).x`
fail_compilation/test12385.d(29): Error: cannot modify `immutable` expression `unbundled.x`
---
*/

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