What is code completion? Symbol suggestions, AI continuations, and applied edits
Understand language-service and generative completion through a list-processing function, including context, acceptance, version matching, and runtime checks.
Understand the concept
Code completion suggests symbols, parameters, or code while editing through language analysis or AI generation. Language services often use types and definitions; AI may predict longer implementations or edits elsewhere. Displayed suggestions are not applied code, and acceptance does not establish runtime correctness. Check versions and behavior.
Language services and AI generation use different evidence
Language services can list methods from a known type, while AI predicts logic from nearby code. VS Code documents these separately. Verify AI-suggested API names through definitions or versioned docs rather than assuming availability.
Filtering missing values with if x also removes valid zeros. Valid syntax is not correct semantics. This example illustrates checking without tool-accuracy or typing-time measurements.
Context and acceptance determine the resulting change
Copilot describes cursor and next-edit suggestions with editor-specific support. Inspect affected lines and the applied diff, including deleted handling or changed error paths, rather than judging the preview alone.
Missing imports or types can lead to unsuitable dependencies. Relevant definitions help diagnosis, while credentials and private account configuration should not be supplied as context. Check actual editor and data settings.
Validate execution after accepting suggestions
Confirm the API and test normal and boundary inputs, including zeros separately from missing values. Avoid tests that merely repeat implementation assumptions. These are validation steps without a completion-service run.
Multi-file planning and command execution go beyond simple completion and need agent or workflow controls. Completion assists editing rather than proving delivery. Diffs and relevant checks matter more than acceptance counts.
Checked sources
These sources support the concepts and methods described here. Examples and test scope are labeled separately; check the version of the tools you use.