hicpp-multiway-paths-covered

This check discovers situations where code paths are not fully-covered. It furthermore suggests using if instead of switch if the code will be more clear. The rule 6.1.2 and rule 6.1.4 of the High Integrity C++ Coding Standard are enforced.

if-else if chains that miss a final else branch might lead to unexpected program execution and be the result of a logical error. If the missing else branch is intended you can leave it empty with a clarifying comment. This warning can be noisy on some code bases, so it is disabled by default.

void f1() {
  int i = determineTheNumber();

   if(i > 0) {
     // Some Calculation
   } else if (i < 0) {
     // Precondition violated or something else.
   }
   // ...
}

Similar arguments hold for switch statements which do not cover all possible code paths.

// The missing default branch might be a logical error. It can be kept empty
// if there is nothing to do, making it explicit.
void f2(int i) {
  switch (i) {
  case 0: // something
    break;
  case 1: // something else
    break;
  }
  // All other numbers?
}

// Violates this rule as well, but already emits a compiler warning (-Wswitch).
enum Color { Red, Green, Blue, Yellow };
void f3(enum Color c) {
  switch (c) {
  case Red: // We can't drive for now.
    break;
  case Green:  // We are allowed to drive.
    break;
  }
  // Other cases missing
}

The rule 6.1.4 requires every switch statement to have at least two case labels other than a default label. Otherwise, the switch could be better expressed with an if statement. Degenerated switch statements without any labels are caught as well.

// Degenerated switch that could be better written as `if`
int i = 42;
switch(i) {
  case 1: // do something here
  default: // do something else here
}

// Should rather be the following:
if (i == 1) {
  // do something here
}
else {
  // do something here
}

// A completely degenerated switch will be diagnosed.
int i = 42;
switch(i) {}

Options

WarnOnMissingElse

Boolean flag that activates a warning for missing else branches. Default is false.