swiftlang/swift

[SR-6736] Enforce 16-bit limit for # of function parameters, # of tuple type element

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#49,285 opened on Jan 11, 2018

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Description
Previous ID SR-6736
Radar None
Original Reporter @DougGregor
Type Bug
Votes 0
Component/s Compiler
Labels Bug, StarterBug
Assignee None
Priority Medium

md5: ea27fac0ee252473c9618a9257498092

Issue Description:

Swift's ABI uses 16 bits to store the number of parameter types in a function type and the number of element types in a tuple type. We should enforce these limits in the parser, so they don't slip through and become crashes at later phases.

Contributor guide

Tech stack
swift
Domain
developer experience
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Swift compiler internalsABI understandingParser design
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50
Research direction
Search the Swift compiler's source code, particularly in the parser (lib/Parse) for places where function types and tuple types are constructed. Add checks to ensure the number of parameters or elements does not exceed the 16 bit limit (65535). If the limit is exceeded, emit a diagnostic error. Write corresponding tests to validate the new behavior. Examine existing tests for similar limit enforcement to follow the pattern.
[SR-6736] Enforce 16-bit limit for # of function parameters, # of tuple type element · swiftlang/swift#49285 | Good First Issue