为什么gcc警告我这条线是"误导性地缩进,就好像它被"一个if？

Question

警告是:

/home/dronz/OF/apps/myApps/HexMap/src/HexMap.cpp:48:5: warning: this ‘if’ clause 
does not guard... [-Wmisleading-indentation]
     if (toHexSize < 1)
     ^~
/home/dronz/OF/apps/myApps/HexMap/src/HexMap.cpp:51:2: note: ...this statement, 
but the latter is misleadingly indented as if it were guarded by the ‘if’
  MapTileSizeAtZoom = toHexSize;
  ^~~~~~~~~~~~~~~~~

代码是这样的:

if (toHexSize < 1)
    toHexSize = 1;

MapTileSizeAtZoom = toHexSize;

如果MapTileSizeAtZoom ...线条缩进更多,我可以看到它有误导性,但它与'if'处于相同的缩进水平,所以这对我来说似乎是正确的.

我想也许有额外的空间和/或标签浮动,但我在文本后删除了任何不必要的空白字符,这没有任何区别.

我想也许它被空白线弄糊涂了,但把它取出并没有停止警告.

此外,在相同的.cpp文件之前是这段代码,它没有警告:

if (toHexSize < 1)
    toHexSize = 1;

HexInfo centerOnHex;
if (SelectedHex.type != -1)

所以我想知道为什么它会警告一个(根本),以及它为什么不警告另一个,这是否是一个gcc bug,以及如何避免它？

...

编辑:@NeilButterworth让我发布"所有代码".(似乎没有相关性,但他有2.5万的声誉,所以我在下面添加了它.)

#include "HexMap.h"
#include <algorithm>
#include <cmath>

//--------------------------------------------------------------
HexMap::HexMap()
{}

//--------------------------------------------------------------
int HexMap::SetZoom(int toHexSize)
{
    if (toHexSize < 1)
        toHexSize = 1;

    HexInfo centerOnHex;
    if (SelectedHex.type != -1)
    {
        // Center map on the selected hex.
        centerOnHex = SelectedHex;
    }
    else
    {
        // Center map on current center of viewpoint.
        centerOnHex = GetHex(
            MapFrame.x + MapFrame.getWidth() / 2,
            MapFrame.y + MapFrame.getHeight() / 2 );
        if ((centerOnHex.x > WORLDMAPWIDTH) || (centerOnHex.x < 0))
            centerOnHex.x = WORLDMAPWIDTH / 2;
        if ((centerOnHex.y > WORLDMAPHEIGHT) || (centerOnHex.y < 0))
            centerOnHex.y = WORLDMAPHEIGHT / 2;
    }

    setHexDisplaySize(toHexSize);

    // Center map:
    HexOriginX = MapFrame.x + MapTileWidth  * 0.25f;
    HexOriginY = MapFrame.y + MapTileHeight * 0.5f;
    ViewPosOnWorld.set(
        centerOnHex.x - (MapFrame.getWidth() / 2) / MapTileWidth, 
        centerOnHex.y - (MapFrame.getHeight() / 2) / MapTileHeight);

    return 0;
}

//--------------------------------------------------------------
void HexMap::setHexDisplaySize(int toHexSize)
{
    if (toHexSize < 1)
        toHexSize = 1;

    MapTileSizeAtZoom = toHexSize;
    MapTileWidth = MapTileSizeAtZoom * 1.5f; // hex x-spacing is 1.5 * r
    MapTileHeight = MapTileSizeAtZoom * 1.73205f; // hex height = sqrt(3*r)

    // Size images & hexmask:
    MaskWidth = MapTileHeight * 1.154700538;  // 1/(sqrt(3)/2)
}

Answer 1

在这里输入所有这个问题之后,我自然发现有用于缩进条件行49的空格,但是使用制表符来缩进第51行.

所以我想我也可以回答我自己的问题而不是删除它,以防其他人对此感到困惑.

有意义的是编译器无法比较空格和制表符,所以它不是一个错误.这是与空格缩进一致的另一个原因(例如,通过避免在源代码中使用任何选项卡).