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<H1> 3.11.1 Completions of Declarations</H1>
<DIV Class="Paranum"><FONT SIZE=-2>1/1</FONT></DIV>
<DIV Class="Normal"> {<I><A HREF="defect1.html#8652/0014">8652/0014</A></I>}
Declarations sometimes come in two parts. <A NAME="I2244"></A>A declaration
that requires a second part is said to <I>require completion</I>. <A NAME="I2245"></A>The
second part is called the <I>completion</I> of the declaration (and of
the entity declared), and is either another declaration, a body, or a
<FONT FACE="Arial, Helvetica">pragma</FONT>. <U>A <A NAME="I2246"></A><I>body</I>
is a <FONT FACE="Arial, Helvetica">body</FONT>, an <FONT FACE="Arial, Helvetica">entry_body</FONT>,
or a renaming-as-body (see <A HREF="AA-8-5-4.html">8.5.4</A>).</U> </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>1.a</FONT></DIV>
<DIV Class="Annotations" Style="margin-bottom: 0.4em"><FONT SIZE=-1><B>Discussion:
</B>Throughout the RM95, there are rules about completions that define
the following: </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>1.b</FONT></DIV>
<UL Class="SmallBulleted"><FONT SIZE=-1><LI TYPE=DISC>Which declarations require a corresponding completion.</LI></FONT></UL>
<DIV Class="Paranum"><FONT SIZE=-2>1.c</FONT></DIV>
<UL Class="SmallBulleted"><FONT SIZE=-1><LI TYPE=DISC>Which constructs can only serve as the completion of a
declaration.</LI></FONT></UL>
<DIV Class="Paranum"><FONT SIZE=-2>1.d</FONT></DIV>
<UL Class="SmallBulleted"><FONT SIZE=-1><LI TYPE=DISC>Where the completion of a declaration is allowed to be.</LI></FONT></UL>
<DIV Class="Paranum"><FONT SIZE=-2>1.e</FONT></DIV>
<UL Class="SmallBulleted"><FONT SIZE=-1><LI TYPE=DISC>What kinds of completions are allowed to correspond to
each kind of declaration that allows one. </LI></FONT></UL>
<DIV Class="Paranum"><FONT SIZE=-2>1.f</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>Don't confuse this compile-time
concept with the run-time concept of completion defined in <A HREF="AA-7-6-1.html">7.6.1</A>.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>1.g</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>Note that the declaration of a
private type (if limited) can be completed with the declaration of a
task type, which is then completed with a body. Thus, a declaration can
actually come in <I>three</I> parts. </FONT></DIV>
<H4 ALIGN=CENTER>Name Resolution Rules</H4>
<DIV Class="Paranum"><FONT SIZE=-2>2</FONT></DIV>
<DIV Class="Normal" Style="margin-bottom: 0.4em"> A construct that
can be a completion is interpreted as the completion of a prior declaration
only if: </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>3</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>The declaration and the completion occur immediately within
the same declarative region;</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>4</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>The defining name or <FONT FACE="Arial, Helvetica">defining_program_unit_name</FONT>
in the completion is the same as in the declaration, or in the case of
a <FONT FACE="Arial, Helvetica">pragma</FONT>, the <FONT FACE="Arial, Helvetica">pragma</FONT>
applies to the declaration;</LI></UL>
<DIV Class="Paranum"><FONT SIZE=-2>5</FONT></DIV>
<UL Class="Bulleted"><LI TYPE=DISC>If the declaration is overloadable, then the completion
either has a type-conformant profile, or is a <FONT FACE="Arial, Helvetica">pragma</FONT>.
<A NAME="I2247"></A></LI></UL>
<H4 ALIGN=CENTER>Legality Rules</H4>
<DIV Class="Paranum"><FONT SIZE=-2>6</FONT></DIV>
<DIV Class="Normal"> An implicit declaration shall not have a completion.
<A NAME="I2248"></A>For any explicit declaration that is specified to
<I>require completion</I>, there shall be a corresponding explicit completion.
</DIV>
<DIV Class="Paranum"><FONT SIZE=-2>6.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Discussion: </B>The implicit
declarations of predefined operators are not allowed to have a completion.
Enumeration literals, although they are subprograms, are not allowed
to have a corresponding <FONT FACE="Arial, Helvetica">subprogram_body</FONT>.
That's because the completion rules are described in terms of constructs
(<FONT FACE="Arial, Helvetica">subprogram_declaration</FONT>s) and not
entities (subprograms). When a completion is required, it has to be explicit;
the implicit null <FONT FACE="Arial, Helvetica">package_body</FONT> that
Section 7 talks about cannot serve as the completion of a <FONT FACE="Arial, Helvetica">package_declaration</FONT>
if a completion is required. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7</FONT></DIV>
<DIV Class="Normal"> At most one completion is allowed for a given
declaration. Additional requirements on completions appear where each
kind of completion is defined. </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Ramification: </B>A subunit
is not a completion; the stub is.</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>7.b</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>If the completion of a declaration
is also a declaration, then <I>that</I> declaration might have a completion,
too. For example, a limited private type can be completed with a task
type, which can then be completed with a task body. This is not a violation
of the ``at most one completion'' rule. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8</FONT></DIV>
<DIV Class="Normal"> <A NAME="I2249"></A>A type is <I>completely defined</I>
at a place that is after its full type definition (if it has one) and
after all of its subcomponent types are completely defined. A type shall
be completely defined before it is frozen (see <A HREF="AA-13-14.html">13.14</A>
and <A HREF="AA-7-3.html">7.3</A>). </DIV>
<DIV Class="Paranum"><FONT SIZE=-2>8.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Reason: </B>Index types are
always completely defined -- no need to mention them. There is no way
for a completely defined type to depend on the value of a (still) deferred
constant. </FONT></DIV>
<DIV Class="NotesHeader"><FONT SIZE=-1>NOTES</FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>9</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>88 Completions are in principle
allowed for any kind of explicit declaration. However, for some kinds
of declaration, the only allowed completion is a <FONT FACE="Arial, Helvetica">pragma</FONT>
Import, and implementations are not required to support <FONT FACE="Arial, Helvetica">pragma</FONT>
Import for every kind of entity. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>9.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1><B>Discussion: </B>In fact, we
expect that implementations will <I>not</I> support pragma Import of
things like types -- it's hard to even define the semantics of what it
would mean. Therefore, in practice, <I>not</I> every explicit declaration
can have a completion. In any case, if an implementation chooses to support
pragma Import for, say, types, it can place whatever restrictions on
the feature it wants to. For example, it might want the <FONT FACE="Arial, Helvetica">pragma</FONT>
to be a freezing point for the type. </FONT></DIV>
<DIV Class="Paranum"><FONT SIZE=-2>10</FONT></DIV>
<DIV Class="Notes"><FONT SIZE=-1>89 There are rules that prevent
premature uses of declarations that have a corresponding completion.
The Elaboration_Checks of <A HREF="AA-3-11.html">3.11</A> prevent such
uses at run time for subprograms, protected operations, tasks, and generic
units. The rules of <A HREF="AA-13-14.html">13.14</A>, ``<A HREF="AA-13-14.html">Freezing
Rules</A>'' prevent, at compile time, premature uses of other entities
such as private types and deferred constants. </FONT></DIV>
<H4 ALIGN=CENTER>Wording Changes from Ada 83</H4>
<DIV Class="Paranum"><FONT SIZE=-2>10.a</FONT></DIV>
<DIV Class="Annotations"><FONT SIZE=-1>This subclause is new. It is intended
to cover all kinds of completions of declarations, be they a body for
a spec, a full type for an incomplete or private type, a full constant
declaration for a deferred constant declaration, or a <FONT FACE="Arial, Helvetica">pragma</FONT>
Import for any kind of entity. </FONT></DIV>
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