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<div class="gmail_quote">On 21/06/2020 19:59, Richard Smith wrote:<br>
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<p>If I understand your suggestion, given</p>
<p><br>
```<br>
struct B<br>
{<br>
B(int);<br>
};<br>
<br>
B func1() {<br>
return 42;<br>
}<br>
```<br>
</p>
<p>a matcher like
`returnStmt(hasReturnValue(fooExpr()))`<br>
</p>
<p>would match for `fooExpr` as any of<br>
</p>
<br>
* exprWithCleanups()<br>
* cxxConstructExpr() (twice)<br>
* materializeTemporaryExpr()<br>
* implicitCastExpr()<br>
* integerLiteral()
<p>right?<br>
</p>
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<div>Yes.</div>
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<p> </p>
<p>and a matcher like
`returnStmt(hasReturnValue(expr().bind("theReturnVal")))`</p>
<p>would bind "theReturnVal" to the
`exprWithCleanups()` right?<br>
</p>
<p>Your suggestion may be that it should bind to the
integerLiteral() in that case. That may have more
scope for confusion though?</p>
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<div>I think that's an interesting question. My
inclination would be to bind to the ExprWithCleanups.
<br>
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<p><br>
</p>
<p>The main reason I'm not supportive of this idea is that I want to
make clang-query tell the user what matchers they can use with the
nodes in the binding list.<br>
</p>
<p>For example, if I write<br>
</p>
<p> returnStmt()</p>
<p>in clang-query it should tell me that I can write <br>
</p>
<p> hasReturnValue(integerLiteral())<br>
</p>
<p>inside the expr():</p>
<p> <a class="moz-txt-link-freetext" href="http://ce.steveire.com/z/9EF8x0">http://ce.steveire.com/z/9EF8x0</a></p>
<p>That's how I as a newcomer quickly discover hasReturnValue() and
integerLiteral().</p>
<p>You have no idea how overwhelming <br>
</p>
<p> <a class="moz-txt-link-freetext" href="http://clang.llvm.org/docs/LibASTMatchersReference.html">http://clang.llvm.org/docs/LibASTMatchersReference.html</a><br>
</p>
<p>is to someone who has zero familiarity with the clang AST.</p>
<p>But the above link is interactive and it aids *discovery* which
is what my talk was about and which is what I'm trying to make
easier with AST Matchers. The above suggested clang-query feature
(not upstream yet) tells me at every step which matchers I can use
in the context of what I am trying to achieve.<br>
</p>
<p>However, if all of the implicit nodes should also appear in that
output, and if in<br>
</p>
<p>`returnStmt(hasReturnValue(expr().bind("theReturnVal")))`</p>
<p>the expr() should match the exprWithCleanups(), then I don't know
how to make that feature work. If the expr() is the
exprWithCleanups() then the tool definitely shouldn't tell the
user they can write integerLiteral() there. The output for
implicit nodes would add lots of noise and would have to be
neutral in terms of what it recommends.<br>
</p>
<p>The entire point of what I'm trying to do is not present the user
with exprWithCleanups() and let them achieve their goals without
it. I don't know if that's possible with the ideas floating around
at the moment about making AST Matchers present all of the
implicit nodes.</p>
<p>But, if making IgnoreUnlessSpelledInSource non-default means that
I can continue work toward that goal (and eg ignore template
instantiations and other implicit nodes which are not skipped
yet), then maybe that's a viable way forward. So, that's my
preference now I think.<br>
</p>
<p>That way, people who want expert mode get it by default, and
newcomers (and anyone else who doesn't want to write
ignoringImplicit() everywhere) can relatively easily get the
easier mode, and can use the expert mode when wanting to match
implicit nodes. <br>
</p>
<p>That might be the best compromise.<br>
</p>
<p>Thanks,</p>
<p>Stephen<br>
</p>
<p><br>
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