$gcc problemMatcher doesn't show all errors or warnings

I have a Visual Studio Code C project based on CMake, compiled using gcc. I've created a custom task for building the project, and have specified $gcc for its problemMatcher property.

However, when I build and there are compile errors, it never displays all the errors and warning messages. Very often it only displays the first one. Sometimes it displays two or three. If there is a warning message that comes up in the list before errors, it will consistently only display that one warning and not show any of the subsequent errors.

How do I fix this? VS Code's CMake tools and C/C++ extensions are the latest version.

Here is my tasks.json:

{"version": "2.0.0","tasks": [        {"type": "cmake","label": "CMake: build application","command": "build","presentation": {"echo": false,"reveal": "always","focus": false,"close": false,"panel": "dedicated","revealProblems": "onProblem","showReuseMessage": false,"clear": true            },"targets": ["all"            ],"group": {"kind": "build","isDefault": true            },"detail": "CMake build task","problemMatcher": ["$gcc"]        }    ]}