Fixed updateReferences() not always updating ident.declaration properly when ident.declaration==ident should have been true (which sometimes broke minify() and maybe more).

Author: ReFreezed

dumbParser.lua

@@ -3501,8 +3501,8 @@ end
 
 
 
--- declIdent|nil    = findIdentifierDeclaration( ident )
--- declIdent.parent = decl|func|forLoop
+-- declIdent | nil  = findIdentifierDeclaration( ident )
+-- declIdent.parent = decl | func | forLoop
 local function findIdentifierDeclaration(ident)
 	local name   = ident.name
 	local parent = ident
@@ -3516,20 +3516,30 @@ local function findIdentifierDeclaration(ident)
 		if parent.type == "declaration" then
 			local decl = parent
 
-			if lastChild.container ~= decl.values then
-				local declIdent = lastItemWith1(decl.names, "name", name)
-				if declIdent then  return declIdent  end
+			if lastChild.container == decl.names then
+				assert(lastChild == ident)
+				return ident -- ident is the declaration node.
 			end
 
 		elseif parent.type == "function" then
-			local func      = parent
-			local declIdent = lastItemWith1(func.parameters, "name", name) -- Note: This will ignore any vararg parameter.
-			if declIdent then  return declIdent  end
+			local func = parent
+
+			if lastChild.container == func.parameters then
+				assert(lastChild == ident)
+				return ident -- ident is the declaration node.
+			else
+				local func      = parent
+				local declIdent = lastItemWith1(func.parameters, "name", name) -- Note: This will ignore any vararg parameter.
+				if declIdent then  return declIdent  end
+			end
 
 		elseif parent.type == "for" then
 			local forLoop = parent
 
-			if lastChild.container ~= forLoop.values then
+			if lastChild.container == forLoop.names then
+				assert(lastChild == ident)
+				return ident -- ident is the declaration node.
+			elseif lastChild.container ~= forLoop.values then
 				local declIdent = lastItemWith1(forLoop.names, "name", name)
 				if declIdent then  return declIdent  end
 			end
@@ -4144,6 +4154,7 @@ local function getInformationAboutIdentifiersAndUpdateReferences(node)
 				statementOrInterest, block = findParentStatementAndBlockOrNodeOfInterest(block, currentDeclIdent)
 
 				if not statementOrInterest then
+					-- We should only get here for globals (i.e. there should be no declaration).
 					assert(not currentDeclIdent)
 					return
 				end

testsuite.lua

@@ -915,6 +915,32 @@ test("Minify", function()
 		[[ for e,t in ipairs(global)do globalFunc1(t);for e=e,#global do globalFunc2(e);end end ]]
 	)
 
+	-- Make sure we minify multi-name declaration-likes as much as possible without shadowing too much.
+	testMinify(
+		[[ local x, y = 1, 2 ; return x ]],
+		[[ local e,t=1,2;return e; ]]
+	)
+	testMinify(
+		[[ local x, y = 1, 2 ; return y ]],
+		[[ local e,e=1,2;return e; ]]
+	)
+	testMinify(
+		[[ for x, y in 1, 2 do return x end ]],
+		[[ for e,t in 1,2 do return e;end ]]
+	)
+	testMinify(
+		[[ for x, y in 1, 2 do return y end ]],
+		[[ for e,e in 1,2 do return e;end ]]
+	)
+	testMinify(
+		[[ function f(x, y) return x end ]],
+		[[ function f(e,t)return e;end ]]
+	)
+	testMinify(
+		[[ function f(x, y) return y end ]],
+		[[ function f(e,e)return e;end ]]
+	)
+
 	if _VERSION >= "Lua 5.2" then
 		testMinify(
 			[[
@@ -926,6 +952,39 @@ test("Minify", function()
 			[[ local _ENV=_ENV;local function e()return _ENV;end ]]
 		)
 	end
+
+	-- Check that declaration references don't change.
+	for _, filename in ipairs{"test.lua","dumbParser.lua"} do
+		local ast   = assert(parser.parseFile(filename))
+		local names = {}
+		local decls = {}
+
+		parser.updateReferences(ast)
+
+		parser.traverseTree(ast, function(node)
+			if node.type == "identifier" then
+				names[node] = node.name
+				decls[node] = node.declaration
+			end
+		end)
+
+		parser.minify(ast)
+		parser.updateReferences(ast)
+		-- print("----------------------------------------------------------------") ; print(parser.toLua(ast, true))
+
+		local ok = true
+
+		parser.traverseTree(ast, function(node)
+			if node.type == "identifier" and node.declaration ~= decls[node] then
+				ok = false
+				print(parser.formatMessage(node, "Declaration changed for '%s' (is '%s').", names[node], node.name))
+				print(decls[node]      and parser.formatMessage(decls[node]     , "from..."):gsub("[^\n]+", "    %0") or "from... nil")
+				print(node.declaration and parser.formatMessage(node.declaration,   "to..."):gsub("[^\n]+", "    %0") or   "to... nil")
+			end
+		end)
+
+		assert(ok, "Declarations changed!")
+	end
 end)