From 06300e82bc6c47e0ad3e25891b1765ec5bf651a0 Mon Sep 17 00:00:00 2001
From: Ewan Mellor <commits@ewanmellor.org>
Date: Thu, 9 Nov 2017 14:44:50 -0800
Subject: [PATCH] [Swift] Make all the mutexes "let" rather than "var".

Make all the mutexes in the Swift runtime use "let" rather than "var".

They are never changed, and they wouldn't make good mutexes if they were.
---
 runtime/Swift/Sources/Antlr4/Parser.swift                 | 4 ++--
 runtime/Swift/Sources/Antlr4/atn/LexerATNSimulator.swift  | 4 ++--
 runtime/Swift/Sources/Antlr4/atn/ParserATNSimulator.swift | 4 ++--
 runtime/Swift/Sources/Antlr4/dfa/DFA.swift                | 2 +-
 4 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/runtime/Swift/Sources/Antlr4/Parser.swift b/runtime/Swift/Sources/Antlr4/Parser.swift
index a031aaf88..5e8ae51f5 100644
--- a/runtime/Swift/Sources/Antlr4/Parser.swift
+++ b/runtime/Swift/Sources/Antlr4/Parser.swift
@@ -61,12 +61,12 @@ open class Parser: Recognizer<ParserATNSimulator> {
     /// 
     /// mutex for bypassAltsAtnCache updates
     /// 
-    private var bypassAltsAtnCacheMutex = Mutex()
+    private let bypassAltsAtnCacheMutex = Mutex()
     
     /// 
     /// mutex for decisionToDFA updates
     /// 
-    private var decisionToDFAMutex = Mutex()
+    private let decisionToDFAMutex = Mutex()
 
     /// 
     /// This field maps from the serialized ATN string to the deserialized _org.antlr.v4.runtime.atn.ATN_ with
diff --git a/runtime/Swift/Sources/Antlr4/atn/LexerATNSimulator.swift b/runtime/Swift/Sources/Antlr4/atn/LexerATNSimulator.swift
index 5f7f619bf..7f541ecc4 100644
--- a/runtime/Swift/Sources/Antlr4/atn/LexerATNSimulator.swift
+++ b/runtime/Swift/Sources/Antlr4/atn/LexerATNSimulator.swift
@@ -77,12 +77,12 @@ open class LexerATNSimulator: ATNSimulator {
     /// 
     /// mutex for DFAState change
     /// 
-    private var dfaStateMutex = Mutex()
+    private let dfaStateMutex = Mutex()
     
     /// 
     /// mutex for changes to all DFAStates map
     /// 
-    private var dfaStatesMutex = Mutex()
+    private let dfaStatesMutex = Mutex()
 
     /// 
     /// Used during DFA/ATN exec to record the most recent accept configuration info
diff --git a/runtime/Swift/Sources/Antlr4/atn/ParserATNSimulator.swift b/runtime/Swift/Sources/Antlr4/atn/ParserATNSimulator.swift
index 530738b22..86bee19cc 100644
--- a/runtime/Swift/Sources/Antlr4/atn/ParserATNSimulator.swift
+++ b/runtime/Swift/Sources/Antlr4/atn/ParserATNSimulator.swift
@@ -281,12 +281,12 @@ open class ParserATNSimulator: ATNSimulator {
     /// 
     /// mutex for DFAState change
     /// 
-    private var dfaStateMutex = Mutex()
+    private let dfaStateMutex = Mutex()
     
     /// 
     /// mutex for changes in a DFAStates map
     /// 
-    private var dfaStatesMutex = Mutex()
+    private let dfaStatesMutex = Mutex()
 
 //    /// Testing only!
 //    public convenience init(_ atn : ATN, _ decisionToDFA : [DFA],
diff --git a/runtime/Swift/Sources/Antlr4/dfa/DFA.swift b/runtime/Swift/Sources/Antlr4/dfa/DFA.swift
index 3f8096ca1..d2fdad9c3 100644
--- a/runtime/Swift/Sources/Antlr4/dfa/DFA.swift
+++ b/runtime/Swift/Sources/Antlr4/dfa/DFA.swift
@@ -32,7 +32,7 @@ public class DFA: CustomStringConvertible {
     /// 
     /// mutex for DFAState changes.
     /// 
-    private var dfaStateMutex = Mutex()
+    private let dfaStateMutex = Mutex()
 
     public convenience init(_ atnStartState: DecisionState) {
         self.init(atnStartState, 0)