tmp/tmp_a3riu0q/{from.md → to.md}
RENAMED
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@@ -3,22 +3,22 @@
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There is an ambiguity in the grammar involving *expression-statement*s
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and *declaration*s: An *expression-statement* with a function-style
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explicit type conversion [[expr.type.conv]] as its leftmost
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subexpression can be indistinguishable from a *declaration* where the
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first *declarator* starts with a `(`. In those cases the *statement* is
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a *declaration*.
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[*Note 1*:
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If the *statement* cannot syntactically be a *declaration*, there is no
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ambiguity, so this rule does not apply. In some cases, the whole
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*statement* needs to be examined to determine whether this is the case.
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This resolves the meaning of many examples.
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[*Example 1*:
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-
Assuming `T` is a *simple-type-specifier* [[dcl.type]],
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``` cpp
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T(a)->m = 7; // expression-statement
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T(a)++; // expression-statement
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T(a,5)<<c; // expression-statement
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@@ -89,11 +89,47 @@ void f() {
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}
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```
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— *end example*]
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<!-- Link reference definitions -->
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[basic.life]: basic.md#basic.life
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[basic.lookup.argdep]: basic.md#basic.lookup.argdep
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[basic.lookup.unqual]: basic.md#basic.lookup.unqual
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[basic.scope]: basic.md#basic.scope
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[basic.scope.block]: basic.md#basic.scope.block
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@@ -107,27 +143,36 @@ void f() {
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[class.dtor]: class.md#class.dtor
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[class.member.lookup]: basic.md#class.member.lookup
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[class.temporary]: basic.md#class.temporary
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[conv]: expr.md#conv
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[conv.prom]: expr.md#conv.prom
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-
[dcl
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[dcl.fct.def.coroutine]: dcl.md#dcl.fct.def.coroutine
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[dcl.init]: dcl.md#dcl.init
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[dcl.meaning]: dcl.md#dcl.meaning
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[dcl.spec.auto]: dcl.md#dcl.spec.auto
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-
[dcl.
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[except.ctor]: except.md#except.ctor
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[expr.await]: expr.md#expr.await
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[expr.const]: expr.md#expr.const
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[expr.context]: expr.md#expr.context
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[expr.type.conv]: expr.md#expr.type.conv
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[stmt.ambig]: #stmt.ambig
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[stmt.block]: #stmt.block
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[stmt.break]: #stmt.break
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[stmt.cont]: #stmt.cont
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[stmt.dcl]: #stmt.dcl
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[stmt.do]: #stmt.do
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[stmt.expr]: #stmt.expr
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[stmt.for]: #stmt.for
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[stmt.goto]: #stmt.goto
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[stmt.if]: #stmt.if
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[stmt.iter]: #stmt.iter
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@@ -139,16 +184,17 @@ void f() {
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[stmt.ranged]: #stmt.ranged
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[stmt.return]: #stmt.return
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[stmt.return.coroutine]: #stmt.return.coroutine
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[stmt.select]: #stmt.select
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[stmt.select.general]: #stmt.select.general
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-
[stmt.stmt]: #stmt.stmt
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[stmt.switch]: #stmt.switch
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[stmt.while]: #stmt.while
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[support.start.term]: support.md#support.start.term
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[temp.pre]: temp.md#temp.pre
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[term.odr.use]: basic.md#term.odr.use
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[^1]: In other words, the `else` is associated with the nearest un-elsed
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`if`.
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[^2]: The transfer from the condition of a `switch` statement to a
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There is an ambiguity in the grammar involving *expression-statement*s
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and *declaration*s: An *expression-statement* with a function-style
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explicit type conversion [[expr.type.conv]] as its leftmost
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subexpression can be indistinguishable from a *declaration* where the
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first *declarator* starts with a `(`. In those cases the *statement* is
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+
considered a *declaration*, except as specified below.
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[*Note 1*:
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If the *statement* cannot syntactically be a *declaration*, there is no
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ambiguity, so this rule does not apply. In some cases, the whole
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*statement* needs to be examined to determine whether this is the case.
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This resolves the meaning of many examples.
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[*Example 1*:
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+
Assuming `T` is a *simple-type-specifier* [[dcl.type.simple]],
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``` cpp
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T(a)->m = 7; // expression-statement
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T(a)++; // expression-statement
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T(a,5)<<c; // expression-statement
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}
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```
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— *end example*]
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A syntactically ambiguous statement that can syntactically be a
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*declaration* with an outermost *declarator* with a
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*trailing-return-type* is considered a *declaration* only if it starts
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with `auto`.
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[*Example 4*:
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``` cpp
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struct M;
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struct S {
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S* operator()();
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int N;
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int M;
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void mem(S s) {
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auto(s)()->M; // expression, S::M hides ::M
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}
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};
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void f(S s) {
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{
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auto(s)()->N; // expression
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auto(s)()->M; // function declaration
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}
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{
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S(s)()->N; // expression
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S(s)()->M; // expression
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}
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}
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```
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— *end example*]
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<!-- Link reference definitions -->
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[basic.contract]: basic.md#basic.contract
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[basic.contract.eval]: basic.md#basic.contract.eval
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[basic.contract.general]: basic.md#basic.contract.general
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[basic.life]: basic.md#basic.life
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[basic.lookup.argdep]: basic.md#basic.lookup.argdep
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[basic.lookup.unqual]: basic.md#basic.lookup.unqual
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[basic.scope]: basic.md#basic.scope
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[basic.scope.block]: basic.md#basic.scope.block
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[class.dtor]: class.md#class.dtor
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[class.member.lookup]: basic.md#class.member.lookup
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[class.temporary]: basic.md#class.temporary
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[conv]: expr.md#conv
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[conv.prom]: expr.md#conv.prom
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[dcl]: dcl.md#dcl
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[dcl.contract.func]: dcl.md#dcl.contract.func
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[dcl.fct.def.coroutine]: dcl.md#dcl.fct.def.coroutine
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[dcl.init]: dcl.md#dcl.init
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[dcl.meaning]: dcl.md#dcl.meaning
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[dcl.pre]: dcl.md#dcl.pre
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[dcl.spec.auto]: dcl.md#dcl.spec.auto
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[dcl.struct.bind]: dcl.md#dcl.struct.bind
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[dcl.type.simple]: dcl.md#dcl.type.simple
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[except.ctor]: except.md#except.ctor
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[expr.await]: expr.md#expr.await
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[expr.call]: expr.md#expr.call
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[expr.const]: expr.md#expr.const
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[expr.context]: expr.md#expr.context
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[expr.type.conv]: expr.md#expr.type.conv
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[intro.execution]: basic.md#intro.execution
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[meta.rel]: meta.md#meta.rel
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[stmt]: #stmt
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[stmt.ambig]: #stmt.ambig
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[stmt.block]: #stmt.block
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[stmt.break]: #stmt.break
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[stmt.cont]: #stmt.cont
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[stmt.contract.assert]: #stmt.contract.assert
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[stmt.dcl]: #stmt.dcl
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[stmt.do]: #stmt.do
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[stmt.expand]: #stmt.expand
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[stmt.expr]: #stmt.expr
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[stmt.for]: #stmt.for
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[stmt.goto]: #stmt.goto
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[stmt.if]: #stmt.if
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[stmt.iter]: #stmt.iter
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[stmt.ranged]: #stmt.ranged
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[stmt.return]: #stmt.return
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[stmt.return.coroutine]: #stmt.return.coroutine
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[stmt.select]: #stmt.select
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[stmt.select.general]: #stmt.select.general
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[stmt.switch]: #stmt.switch
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[stmt.while]: #stmt.while
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[support.start.term]: support.md#support.start.term
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[temp.decls.general]: temp.md#temp.decls.general
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[temp.pre]: temp.md#temp.pre
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[term.odr.use]: basic.md#term.odr.use
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[thread.thread.this]: thread.md#thread.thread.this
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[^1]: In other words, the `else` is associated with the nearest un-elsed
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`if`.
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[^2]: The transfer from the condition of a `switch` statement to a
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