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cleaner fix for Issue 18480 - dmd hangs with self-alias declaration #7954

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Merged
MartinNowak merged 2 commits into from
Feb 27, 2018
Merged

cleaner fix for Issue 18480 - dmd hangs with self-alias declaration #7954

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4a03c0e
Revert "Merge pull request #7930 from timotheecour/pr_fix_18480"
MartinNowak Feb 24, 2018
414ae99
fix Issue 18480 - dmd hangs with self-alias declaration
MartinNowak Feb 24, 2018
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22 changes: 4 additions & 18 deletions src/dmd/access.d
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Original file line number Diff line number Diff line change
Expand Up @@ -547,8 +547,8 @@ public Dsymbol mostVisibleOverload(Dsymbol s)
{
if (!s.isOverloadable())
return s;
Dsymbol next, fstart = s, mostVisible = s, previous = null;
AliasDeclaration adOrig = null;

Dsymbol next, fstart = s, mostVisible = s;
for (; s; s = next)
{
// void func() {}
Expand All @@ -571,7 +571,8 @@ public Dsymbol mostVisibleOverload(Dsymbol s)
// private void name(int) {}
else if (auto ad = s.isAliasDeclaration())
{
assert(ad.isOverloadable, "Non overloadable Aliasee in overload list");
assert(ad.isOverloadable || ad.type && ad.type.ty == Terror,
"Non overloadable Aliasee in overload list");
// Yet unresolved aliases store overloads in overnext.
if (ad.semanticRun < PASS.semanticdone)
next = ad.overnext;
Expand All @@ -593,13 +594,7 @@ public Dsymbol mostVisibleOverload(Dsymbol s)
*/
auto aliasee = ad.toAlias();
if (aliasee.isFuncAliasDeclaration || aliasee.isOverDeclaration)
{
if(ad.toChars() == aliasee.toChars())
{
adOrig = ad;
}
next = aliasee;
}
else
{
/* A simple alias can be at the end of a function or template overload chain.
Expand All @@ -619,15 +614,6 @@ public Dsymbol mostVisibleOverload(Dsymbol s)

if (next && mostVisible.prot().isMoreRestrictiveThan(next.prot()))
mostVisible = next;

// fixes https://issues.dlang.org/show_bug.cgi?id=18480
if(next && next == previous)
{
assert(adOrig);
error(adOrig.loc, "`alias X = X` not allowed (with `X = %s`)", adOrig.toChars());
return next;
}
previous = s;
}
return mostVisible;
}
13 changes: 13 additions & 0 deletions src/dmd/dsymbolsem.d
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Original file line number Diff line number Diff line change
Expand Up @@ -5492,6 +5492,19 @@ void aliasSemantic(AliasDeclaration ds, Scope* sc)
global.gag = 0;
}

// https://issues.dlang.org/show_bug.cgi?id=18480
// Detect `alias sym = sym;` to prevent creating loops in overload overnext lists.
// Selective imports are allowed to alias to the same name `import mod : sym=sym`.
if (ds.type.ty == Tident && !ds._import)
{
auto tident = cast(TypeIdentifier)ds.type;
if (tident.ident is ds.ident && !tident.idents.dim)
{
error(ds.loc, "`alias %s = %s;` cannot alias itself, use a qualified name to create an overload set",
ds.ident.toChars(), tident.ident.toChars());
ds.type = Type.terror;
}
}
/* This section is needed because Type.resolve() will:
* const x = 3;
* alias y = x;
Expand Down
2 changes: 1 addition & 1 deletion test/fail_compilation/test18480.d
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,7 @@
/*
TEST_OUTPUT:
---
fail_compilation/imports/test18480a.d(2): Error: `alias X = X` not allowed (with `X = TestTemplate`)
fail_compilation/imports/test18480a.d(2): Error: `alias TestTemplate = TestTemplate;` cannot alias itself, use a qualified name to create an overload set
---
https://issues.dlang.org/show_bug.cgi?id=18480
*/
Expand Down