Swift 3.0 是一个主要语言发行版本，在源码上与 Swift 2.2 和 2.3 并不兼容，包含了如下的语言特性的变化：
SE-0002: Removing currying func declaration syntax
SE-0003: Removing var from Function Parameters
SE-0004: Remove the ++ and -- operators
SE-0005: Better Translation of Objective-C APIs Into Swift
SE-0006: Apply API Guidelines to the Standard Library
SE-0007: Remove C-style for-loops with conditions and incrementers
SE-0008: Add a Lazy flatMap for Sequences of Optionals
SE-0016: Adding initializers to Int and UInt to convert from UnsafePointer and UnsafeMutablePointer
SE-0017: Change Unmanaged to use UnsafePointer
SE-0019: Swift Testing
SE-0023: API Design Guidelines
SE-0025: Scoped Access Level
SE-0029: Remove implicit tuple splat behavior from function applications
SE-0031: Adjusting inout Declarations for Type Decoration
SE-0032: Add first(where:) method to SequenceType
SE-0033: Import Objective-C Constants as Swift Types
SE-0034: Disambiguating Line Control Statements from Debugging Identifiers
SE-0035: Limiting inout capture to @noescape contexts
SE-0036: Requiring Leading Dot Prefixes for Enum Instance Member Implementations
SE-0037: Clarify interaction between comments & operators
SE-0038: Package Manager C Language Target Support
SE-0039: Modernizing Playground Literals
SE-0040: Replacing Equal Signs with Colons For Attribute Arguments
SE-0043: Declare variables in ‘case’ labels with multiple patterns
SE-0044: Import as Member
SE-0046: Establish consistent label behavior across all parameters including first labels
SE-0047: Defaulting non-Void functions so they warn on unused results
SE-0048: Generic Type Aliases
SE-0049: Move @noescape and @autoclosure to be type attributes
SE-0052: Change IteratorType post-nil guarantee
SE-0053: Remove explicit use of let from Function Parameters
SE-0054: Abolish ImplicitlyUnwrappedOptional type
SE-0055: Make unsafe pointer nullability explicit using Optional
SE-0057: Importing Objective-C Lightweight Generics
SE-0059: Update API Naming Guidelines and Rewrite Set APIs Accordingly
SE-0060: Enforcing order of defaulted parameters
SE-0061: Add Generic Result and Error Handling to autoreleasepool()
SE-0062: Referencing Objective-C key-paths
SE-0063: SwiftPM System Module Search Paths
SE-0064: Referencing the Objective-C selector of property getters and setters
SE-0065: A New Model For Collections and Indices
SE-0066: Standardize function type argument syntax to require parentheses
SE-0067: Enhanced Floating Point Protocols
SE-0069: Mutability and Foundation Value Types
SE-0070: Make Optional Requirements Objective-C-only
SE-0071: Allow (most) keywords in member references
SE-0072: Fully eliminate implicit bridging conversions from Swift
SE-0076: Add overrides taking an UnsafePointer source to non-destructive copying methods on UnsafeMutablePointer
SE-0077: Improved operator declarations
SE-0081: Move where clause to end of declaration
SE-0085: Package Manager Command Names
SE-0086: Drop NS Prefix in Swift Foundation
SE-0088: Modernize libdispatch for Swift 3 naming conventions
SE-0089: Renaming String.init
SE-0091: Improving operator requirements in protocols
SE-0092: Typealiases in protocols and protocol extensions
SE-0093: Adding a public base property to slices
SE-0094: Add sequence(first:next:) and sequence(state:next:) to the stdlib
SE-0095: Replace protocol
SE-0096: Converting dynamicType from a property to an operator
SE-0099: Restructuring Condition Clauses
SE-0101: Reconfiguring sizeof and related functions into a unified MemoryLayoutstruct
SE-0102: Remove @noreturn attribute and introduce an empty Never type
SE-0103: Make non-escaping closures the default
SE-0106: Add a macOS Alias for the OSX Platform Configuration Test
SE-0107: UnsafeRawPointer API
SE-0109: Remove the Boolean protocol
SE-0111: Remove type system significance of function argument labels
SE-0112: Improved NSError Bridging
SE-0113: Add integral rounding functions to FloatingPoint
SE-0114: Updating Buffer "Value" Names to "Header" Names
SE-0115: Rename Literal Syntax Protocols
SE-0116: Import Objective-C id as Swift Any type
SE-0117: Allow distinguishing between public access and public overridability
SE-0118: Closure Parameter Names and Labels
SE-0120: Revise partition Method Signature
SE-0121: Remove Optional Comparison Operators
SE-0124: Int.init(ObjectIdentifier) and UInt.init(ObjectIdentifier)should have a bitPattern: label
SE-0125: Remove NonObjectiveCBase and isUniquelyReferenced
SE-0127: Cleaning up stdlib Pointer and Buffer Routines
SE-0128: Change failable UnicodeScalar initializers to failable
SE-0129: Package Manager Test Naming Conventions
SE-0130: Replace repeating Character and UnicodeScalar forms of String.init
SE-0131: Add AnyHashable to the standard library
SE-0133: Rename flatten() to joined()
SE-0134: Rename two UTF8-related properties on String
SE-0135: Package Manager Support for Differentiating Packages by Swift version
SE-0136: Memory Layout of Values
SE-0137: Avoiding Lock-In to Legacy Protocol Designs
官方发行说明：https://swift.org/blog/swift-3-0-released/
来自:开源中国社区