Everything the compile and the validation say, in one panel, filterable.

the ST Output panel with its severity switches, the search field, and errors in the log

Compiling

Compile on the ST toolbar hands the project to st2cpp, which is a separate command-line binary built from third_party/st2cpp:

cmake -S third_party/st2cpp -B build/st2cpp -DCMAKE_BUILD_TYPE=Release

cmake --build build/st2cpp -j"$(nproc)"

The Editor looks for st2cpp on PATH first and then at build/st2cpp/st2cpp, and prints the path it used at the top of this panel. A missing transpiler is reported plainly and nothing else stops working — it is not an exit status that fails the IDE.

Validate parses and analyses without generating.

The panel


Errors, Warnings, Success, Detail	show or hide each severity, with a count beside it
Generated ST	the generated file in full, off by default
Search output	filter the lines
Copy	the lines currently shown, not the whole log
Clear	empty the panel

The search belongs to the panel and to the workspace it was typed in. A query left over from one project does not filter the next project's log to nothing.

The generated file is not the file you edit

A .st file is not edited as one blob. It is regenerated from the panes being edited, and a source map maps each generated line back to the editor that owns it. A diagnostic is therefore reported against the generated file, and its line numbers mean nothing without that map.

A POU is saved and compiled whole

Save and Compile serialize every method tab of the POU, not only the one on screen. See structured-text.md.