[llvm-bugs] [Bug 48482] New: [clang-analyzer] False report about virtual method during construction

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=48482

            Bug ID: 48482
           Summary: [clang-analyzer] False report about virtual method
                    during construction
           Product: clang
           Version: trunk
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P
         Component: Static Analyzer
          Assignee: dcoughlin at apple.com
          Reporter: dmitry.polukhin at gmail.com
                CC: dcoughlin at apple.com, llvm-bugs at lists.llvm.org

Minimal reproducer:

// clang++ --analyze -Xanalyzer -analyzer-output=text -Xanalyzer
-analyzer-checker='optin.cplusplus'

class Attribute {
public:
  virtual ~Attribute() = default;
  virtual int encode() const = 0;

 protected:
  Attribute() {}
};

class Number : public Attribute {
public:
  explicit Number()
      : Attribute() {}

  int encode() const override;

private:
  int number_;
};

void foo() {
  Number number;
  number.encode();
}

Output:
test.cpp:23:3: warning: Call to virtual method 'Number::encode' during
construction bypasses virtual dispatch
  number.encode();
  ^~~~~~~~~~~~~~~~~~~~~~
test.cpp:23:3: note: Call to virtual method 'Number::encode' during
construction bypasses virtual dispatch
  number.encode();
  ^~~~~~~~~~~~~~~~~~~~~~
1 warning generated.

To trigger this bug it is required to have uninitialised in c-tor member
`number_`. In full example the member was initialised later with member
function call before calling the virtual function. Problem exists starting from
at least clang 9 up to current trunk.

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