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fix: omit the synthesized initializer for default-constructed variables #1239

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fix: omit the synthesized initializer for default-constructed variables #1239

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20 changes: 19 additions & 1 deletion src/lib/AST/ASTVisitor.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1137,6 +1137,23 @@ populate(TypedefSymbol& I, clang::TypeAliasTemplateDecl const* D)
}
}

// A variable with no written initializer can still carry an implicit
// initializer in the AST. Any default-constructed class instance (`T t;`) gets
// an implicit construction expression located at the variable name, so the
// extracted source text is the variable name and would cause a spurious `= t`
// to be rendered in the docs. So, we intercept this case. A written `{}`, a
// copy-initialization such as `= x`, and literal initializers are left alone.
static
bool
isImplicitDefaultInit(clang::Expr const* E)
{
clang::CXXConstructExpr const* ctor =
dyn_cast<clang::CXXConstructExpr>(E->IgnoreImplicit());
return ctor != nullptr
&& ctor->getNumArgs() == 0
&& ctor->getParenOrBraceRange().isInvalid();
}

void
ASTVisitor::
populate(
Expand All @@ -1161,7 +1178,8 @@ populate(
I.IsConstinit |= D->hasAttr<clang::ConstInitAttr>();
I.IsConstexpr |= D->isConstexpr();
I.IsInline |= D->isInline();
if (clang::Expr const* E = D->getInit())
if (clang::Expr const* E = D->getInit();
E && !isImplicitDefaultInit(E))
{
populate(I.Initializer, E);
}
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13 changes: 13 additions & 0 deletions test-files/golden-tests/symbols/variable/default-constructed-instance.cpp
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Original file line number Diff line number Diff line change
@@ -0,0 +1,13 @@
struct tag_base {};

/** A default-constructed instance of a same-named tag type (see issue #1238). */
inline constexpr struct flag final : tag_base {} flag;

/** A copy-initialized variable. */
inline constexpr auto flag_copy = flag;

/** A value-initialized variable. */
inline constexpr tag_base braced{};

/** A variable with a literal initializer. */
inline constexpr int literal = 7;
211 changes: 211 additions & 0 deletions test-files/golden-tests/symbols/variable/default-constructed-instance.xml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,211 @@
<?xml version="1.0" encoding="UTF-8"?>
<mrdocs xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="https://github.com/cppalliance/mrdocs/raw/develop/mrdocs.rnc">
<namespace>
<source>
</source>
<kind>namespace</kind>
<id>//////////////////////////8=</id>
<extraction>regular</extraction>
<namespace-tranche>
<records>5sB+nY7A37FZIfir11OpIKC12Ok=</records>
<records>8tmm5w1vdZa8PYl9AaZ5HNozN/k=</records>
<variables>V/VOefC+Lirvlyv4ml0GPg3tkb8=</variables>
<variables>4BBlDC8MjV0Km82gDuPpLniry80=</variables>
<variables>w7084vhWPkLDZ/7kZBE9YeheM8E=</variables>
<variables>/2+SAVa0lxHgZkikhVVwJfO2tZY=</variables>
</namespace-tranche>
</namespace>
<record>
<name>flag</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>4</line-number>
<column-number>18</column-number>
<documented>1</documented>
</location>
</source>
<kind>record</kind>
<id>5sB+nY7A37FZIfir11OpIKC12Ok=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<doc-comment>
<brief>
<kind>brief</kind>
<text>
<kind>text</kind>
<literal>A default-constructed instance of a same-named tag type (see issue #1238).</literal>
</text>
</brief>
</doc-comment>
<key-kind>struct</key-kind>
<is-final>1</is-final>
<base>
<named>
<name>
<kind>identifier</kind>
<id>8tmm5w1vdZa8PYl9AaZ5HNozN/k=</id>
<identifier>tag_base</identifier>
</name>
</named>
</base>
<record-interface>
<record-tranche>
</record-tranche>
<record-tranche>
</record-tranche>
<record-tranche>
</record-tranche>
</record-interface>
</record>
<record>
<name>tag_base</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>1</line-number>
<column-number>1</column-number>
</location>
</source>
<kind>record</kind>
<id>8tmm5w1vdZa8PYl9AaZ5HNozN/k=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<key-kind>struct</key-kind>
<derived>5sB+nY7A37FZIfir11OpIKC12Ok=</derived>
<record-interface>
<record-tranche>
</record-tranche>
<record-tranche>
</record-tranche>
<record-tranche>
</record-tranche>
</record-interface>
</record>
<variable>
<name>braced</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>10</line-number>
<column-number>1</column-number>
<documented>1</documented>
</location>
</source>
<kind>variable</kind>
<id>V/VOefC+Lirvlyv4ml0GPg3tkb8=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<doc-comment>
<brief>
<kind>brief</kind>
<text>
<kind>text</kind>
<literal>A value-initialized variable.</literal>
</text>
</brief>
</doc-comment>
<named>
<name>
<kind>identifier</kind>
<id>8tmm5w1vdZa8PYl9AaZ5HNozN/k=</id>
<identifier>tag_base</identifier>
</name>
</named>
<initializer>{}</initializer>
<is-inline>1</is-inline>
<is-constexpr>1</is-constexpr>
</variable>
<variable>
<name>flag</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>4</line-number>
<column-number>1</column-number>
</location>
</source>
<kind>variable</kind>
<id>4BBlDC8MjV0Km82gDuPpLniry80=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<named>
<name>
<kind>identifier</kind>
<id>5sB+nY7A37FZIfir11OpIKC12Ok=</id>
<identifier>flag</identifier>
</name>
</named>
<is-inline>1</is-inline>
<is-constexpr>1</is-constexpr>
</variable>
<variable>
<name>flag_copy</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>7</line-number>
<column-number>1</column-number>
<documented>1</documented>
</location>
</source>
<kind>variable</kind>
<id>w7084vhWPkLDZ/7kZBE9YeheM8E=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<doc-comment>
<brief>
<kind>brief</kind>
<text>
<kind>text</kind>
<literal>A copy-initialized variable.</literal>
</text>
</brief>
</doc-comment>
<auto>
</auto>
<initializer>flag</initializer>
<is-inline>1</is-inline>
<is-constexpr>1</is-constexpr>
</variable>
<variable>
<name>literal</name>
<source>
<location>
<short-path>default-constructed-instance.cpp</short-path>
<source-path>default-constructed-instance.cpp</source-path>
<line-number>13</line-number>
<column-number>1</column-number>
<documented>1</documented>
</location>
</source>
<kind>variable</kind>
<id>/2+SAVa0lxHgZkikhVVwJfO2tZY=</id>
<extraction>regular</extraction>
<parent>//////////////////////////8=</parent>
<doc-comment>
<brief>
<kind>brief</kind>
<text>
<kind>text</kind>
<literal>A variable with a literal initializer.</literal>
</text>
</brief>
</doc-comment>
<named>
<name>
<kind>identifier</kind>
<identifier>int</identifier>
</name>
</named>
<initializer>7</initializer>
<is-inline>1</is-inline>
<is-constexpr>1</is-constexpr>
</variable>
</mrdocs>
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