73 lines
2.0 KiB
ReStructuredText
73 lines
2.0 KiB
ReStructuredText
.. title:: clang-tidy - misc-suspicious-semicolon
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misc-suspicious-semicolon
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=========================
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Finds most instances of stray semicolons that unexpectedly alter the meaning of
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the code. More specifically, it looks for ``if``, ``while``, ``for`` and
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``for-range`` statements whose body is a single semicolon, and then analyzes the
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context of the code (e.g. indentation) in an attempt to determine whether that
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is intentional.
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.. code-block:: c++
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if (x < y);
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{
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x++;
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}
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Here the body of the ``if`` statement consists of only the semicolon at the end
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of the first line, and `x` will be incremented regardless of the condition.
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.. code-block:: c++
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while ((line = readLine(file)) != NULL);
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processLine(line);
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As a result of this code, `processLine()` will only be called once, when the
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``while`` loop with the empty body exits with `line == NULL`. The indentation of
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the code indicates the intention of the programmer.
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.. code-block:: c++
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if (x >= y);
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x -= y;
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While the indentation does not imply any nesting, there is simply no valid
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reason to have an `if` statement with an empty body (but it can make sense for
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a loop). So this check issues a warning for the code above.
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To solve the issue remove the stray semicolon or in case the empty body is
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intentional, reflect this using code indentation or put the semicolon in a new
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line. For example:
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.. code-block:: c++
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while (readWhitespace());
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Token t = readNextToken();
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Here the second line is indented in a way that suggests that it is meant to be
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the body of the `while` loop - whose body is in fact empty, because of the
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semicolon at the end of the first line.
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Either remove the indentation from the second line:
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.. code-block:: c++
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while (readWhitespace());
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Token t = readNextToken();
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... or move the semicolon from the end of the first line to a new line:
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.. code-block:: c++
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while (readWhitespace())
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;
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Token t = readNextToken();
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In this case the check will assume that you know what you are doing, and will
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not raise a warning.
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