use === for comparison to nothing and Symbols (JuliaLang#33764)

base/Enums.jl

@@ -121,7 +121,7 @@ macro enum(T, syms...)
     end
     basetype = Int32
     typename = T
-    if isa(T, Expr) && T.head == :(::) && length(T.args) == 2 && isa(T.args[1], Symbol)
+    if isa(T, Expr) && T.head === :(::) && length(T.args) == 2 && isa(T.args[1], Symbol)
         typename = T.args[1]
         basetype = Core.eval(__module__, T.args[2])
         if !isa(basetype, DataType) || !(basetype <: Integer) || !isbitstype(basetype)
@@ -137,7 +137,7 @@ macro enum(T, syms...)
     i = zero(basetype)
     hasexpr = false
 
-    if length(syms) == 1 && syms[1] isa Expr && syms[1].head == :block
+    if length(syms) == 1 && syms[1] isa Expr && syms[1].head === :block
         syms = syms[1].args
     end
     for s in syms
@@ -147,7 +147,7 @@ macro enum(T, syms...)
                 throw(ArgumentError("overflow in value \"$s\" of Enum $typename"))
             end
         elseif isa(s, Expr) &&
-               (s.head == :(=) || s.head == :kw) &&
+               (s.head === :(=) || s.head === :kw) &&
                length(s.args) == 2 && isa(s.args[1], Symbol)
             i = Core.eval(__module__, s.args[2]) # allow exprs, e.g. uint128"1"
             if !isa(i, Integer)

base/arraymath.jl

@@ -48,10 +48,10 @@ function +(A::Array, Bs::Array...)
 end
 
 for f in (:/, :\, :*)
-    if f != :/
+    if f !== :/
         @eval ($f)(A::Number, B::AbstractArray) = broadcast_preserving_zero_d($f, A, B)
     end
-    if f != :\
+    if f !== :\
         @eval ($f)(A::AbstractArray, B::Number) = broadcast_preserving_zero_d($f, A, B)
     end
 end

base/atomics.jl

@@ -398,7 +398,7 @@ for typ in atomictypes
                          ret $lt %rv
                          """, $typ, Tuple{Ptr{$typ}, $typ}, unsafe_convert(Ptr{$typ}, x), v)
         else
-            rmwop == :xchg || continue
+            rmwop === :xchg || continue
             @eval $fn(x::Atomic{$typ}, v::$typ) =
                 llvmcall($"""
                          %iptr = inttoptr i$WORD_SIZE %0 to $ilt*

base/broadcast.jl

@@ -1144,12 +1144,12 @@ Base.@propagate_inbounds dotview(args...) = Base.maybeview(args...)
 dottable(x) = false # avoid dotting spliced objects (e.g. view calls inserted by @view)
 # don't add dots to dot operators
 dottable(x::Symbol) = (!isoperator(x) || first(string(x)) != '.' || x === :..) && x !== :(:)
-dottable(x::Expr) = x.head != :$
+dottable(x::Expr) = x.head !== :$
 undot(x) = x
 function undot(x::Expr)
-    if x.head == :.=
+    if x.head === :.=
         Expr(:(=), x.args...)
-    elseif x.head == :block # occurs in for x=..., y=...
+    elseif x.head === :block # occurs in for x=..., y=...
         Expr(:block, map(undot, x.args)...)
     else
         x
@@ -1158,22 +1158,22 @@ end
 __dot__(x) = x
 function __dot__(x::Expr)
     dotargs = map(__dot__, x.args)
-    if x.head == :call && dottable(x.args[1])
+    if x.head === :call && dottable(x.args[1])
         Expr(:., dotargs[1], Expr(:tuple, dotargs[2:end]...))
-    elseif x.head == :comparison
+    elseif x.head === :comparison
         Expr(:comparison, (iseven(i) && dottable(arg) && arg isa Symbol && isoperator(arg) ?
                                Symbol('.', arg) : arg for (i, arg) in pairs(dotargs))...)
-    elseif x.head == :$
+    elseif x.head === :$
         x.args[1]
-    elseif x.head == :let # don't add dots to `let x=...` assignments
+    elseif x.head === :let # don't add dots to `let x=...` assignments
         Expr(:let, undot(dotargs[1]), dotargs[2])
-    elseif x.head == :for # don't add dots to for x=... assignments
+    elseif x.head === :for # don't add dots to for x=... assignments
         Expr(:for, undot(dotargs[1]), dotargs[2])
-    elseif (x.head == :(=) || x.head == :function || x.head == :macro) &&
+    elseif (x.head === :(=) || x.head === :function || x.head === :macro) &&
            Meta.isexpr(x.args[1], :call) # function or macro definition
         Expr(x.head, x.args[1], dotargs[2])
     else
-        if x.head == :&& || x.head == :||
+        if x.head === :&& || x.head === :||
             error("""
                 Using `&&` and `||` is disallowed in `@.` expressions.
                 Use `&` or `|` for elementwise logical operations.

base/cartesian.jl

@@ -45,7 +45,7 @@ function _nloops(N::Int, itersym::Symbol, arraysym::Symbol, args::Expr...)
 end
 
 function _nloops(N::Int, itersym::Symbol, rangeexpr::Expr, args::Expr...)
-    if rangeexpr.head != :->
+    if rangeexpr.head !== :->
         throw(ArgumentError("second argument must be an anonymous function expression to compute the range"))
     end
     if !(1 <= length(args) <= 3)
@@ -167,7 +167,7 @@ evaluate to `true`.
 can be convenient for bounds-checking.
 """
 macro nall(N::Int, criterion::Expr)
-    if criterion.head != :->
+    if criterion.head !== :->
         throw(ArgumentError("second argument must be an anonymous function expression yielding the criterion"))
     end
     conds = Any[ Expr(:escape, inlineanonymous(criterion, i)) for i = 1:N ]
@@ -183,7 +183,7 @@ evaluate to `true`.
 `@nany 3 d->(i_d > 1)` would generate the expression `(i_1 > 1 || i_2 > 1 || i_3 > 1)`.
 """
 macro nany(N::Int, criterion::Expr)
-    if criterion.head != :->
+    if criterion.head !== :->
         error("Second argument must be an anonymous function expression yielding the criterion")
     end
     conds = Any[ Expr(:escape, inlineanonymous(criterion, i)) for i = 1:N ]
@@ -233,7 +233,7 @@ end
 
 # Simplify expressions like :(d->3:size(A,d)-3) given an explicit value for d
 function inlineanonymous(ex::Expr, val)
-    if ex.head != :->
+    if ex.head !== :->
         throw(ArgumentError("not an anonymous function"))
     end
     if !isa(ex.args[1], Symbol)
@@ -313,7 +313,7 @@ end
 
 function lreplace!(ex::Expr, r::LReplace)
     # Curly-brace notation, which acts like parentheses
-    if ex.head == :curly && length(ex.args) == 2 && isa(ex.args[1], Symbol) && endswith(string(ex.args[1]), "_")
+    if ex.head === :curly && length(ex.args) == 2 && isa(ex.args[1], Symbol) && endswith(string(ex.args[1]), "_")
         excurly = exprresolve(lreplace!(ex.args[2], r))
         if isa(excurly, Number)
             return Symbol(ex.args[1],excurly)
@@ -333,12 +333,12 @@ lreplace!(arg, r::LReplace) = arg
 
 poplinenum(arg) = arg
 function poplinenum(ex::Expr)
-    if ex.head == :block
+    if ex.head === :block
         if length(ex.args) == 1
             return ex.args[1]
         elseif length(ex.args) == 2 && isa(ex.args[1], LineNumberNode)
             return ex.args[2]
-        elseif (length(ex.args) == 2 && isa(ex.args[1], Expr) && ex.args[1].head == :line)
+        elseif (length(ex.args) == 2 && isa(ex.args[1], Expr) && ex.args[1].head === :line)
             return ex.args[2]
         end
     end
@@ -353,7 +353,7 @@ const exprresolve_cond_dict = Dict{Symbol,Function}(:(==) => ==,
     :(<) => <, :(>) => >, :(<=) => <=, :(>=) => >=)
 
 function exprresolve_arith(ex::Expr)
-    if ex.head == :call && haskey(exprresolve_arith_dict, ex.args[1]) && all([isa(ex.args[i], Number) for i = 2:length(ex.args)])
+    if ex.head === :call && haskey(exprresolve_arith_dict, ex.args[1]) && all([isa(ex.args[i], Number) for i = 2:length(ex.args)])
         return true, exprresolve_arith_dict[ex.args[1]](ex.args[2:end]...)
     end
     false, 0
@@ -362,7 +362,7 @@ exprresolve_arith(arg) = false, 0
 
 exprresolve_conditional(b::Bool) = true, b
 function exprresolve_conditional(ex::Expr)
-    if ex.head == :call && ex.args[1] ∈ keys(exprresolve_cond_dict) && isa(ex.args[2], Number) && isa(ex.args[3], Number)
+    if ex.head === :call && ex.args[1] ∈ keys(exprresolve_cond_dict) && isa(ex.args[2], Number) && isa(ex.args[3], Number)
         return true, exprresolve_cond_dict[ex.args[1]](ex.args[2], ex.args[3])
     end
     false, false
@@ -378,12 +378,12 @@ function exprresolve(ex::Expr)
     can_eval, result = exprresolve_arith(ex)
     if can_eval
         return result
-    elseif ex.head == :call && (ex.args[1] == :+ || ex.args[1] == :-) && length(ex.args) == 3 && ex.args[3] == 0
+    elseif ex.head === :call && (ex.args[1] === :+ || ex.args[1] === :-) && length(ex.args) == 3 && ex.args[3] == 0
         # simplify x+0 and x-0
         return ex.args[2]
     end
     # Resolve array references
-    if ex.head == :ref && isa(ex.args[1], Array)
+    if ex.head === :ref && isa(ex.args[1], Array)
         for i = 2:length(ex.args)
             if !isa(ex.args[i], Real)
                 return ex
@@ -392,7 +392,7 @@ function exprresolve(ex::Expr)
         return ex.args[1][ex.args[2:end]...]
     end
     # Resolve conditionals
-    if ex.head == :if
+    if ex.head === :if
         can_eval, tf = exprresolve_conditional(ex.args[1])
         if can_eval
             ex = tf ? ex.args[2] : ex.args[3]

base/channels.jl

@@ -31,7 +31,7 @@ mutable struct Channel{T} <: AbstractChannel{T}
     cond_wait::Threads.Condition                 # waiting for data to become maybe available
     cond_put::Threads.Condition                  # waiting for a writeable slot
     state::Symbol
-    excp::Union{Exception, Nothing}      # exception to be thrown when state != :open
+    excp::Union{Exception, Nothing}      # exception to be thrown when state !== :open
 
     data::Vector{T}
     sz_max::Int                          # maximum size of channel
@@ -189,7 +189,7 @@ function close(c::Channel, excp::Exception=closed_exception())
     end
     nothing
 end
-isopen(c::Channel) = (c.state == :open)
+isopen(c::Channel) = (c.state === :open)
 
 """
     bind(chnl::Channel, task::Task)
@@ -459,7 +459,7 @@ function iterate(c::Channel, state=nothing)
     try
         return (take!(c), nothing)
     catch e
-        if isa(e, InvalidStateException) && e.state == :closed
+        if isa(e, InvalidStateException) && e.state === :closed
             return nothing
         else
             rethrow()

base/client.jl

@@ -94,7 +94,7 @@ function scrub_repl_backtrace(bt)
     if bt !== nothing && !(bt isa Vector{Any}) # ignore our sentinel value types
         bt = stacktrace(bt)
         # remove REPL-related frames from interactive printing
-        eval_ind = findlast(frame -> !frame.from_c && frame.func == :eval, bt)
+        eval_ind = findlast(frame -> !frame.from_c && frame.func === :eval, bt)
         eval_ind === nothing || deleteat!(bt, eval_ind:length(bt))
     end
     return bt

base/compiler/optimize.jl

@@ -157,7 +157,7 @@ function stmt_affects_purity(@nospecialize(stmt), ir)
         return !(t ⊑ Bool)
     end
     if isa(stmt, Expr)
-        return stmt.head != :loopinfo && stmt.head != :enter
+        return stmt.head !== :loopinfo && stmt.head !== :enter
     end
     return true
 end
@@ -167,7 +167,7 @@ function optimize(opt::OptimizationState, @nospecialize(result))
     def = opt.linfo.def
     nargs = Int(opt.nargs) - 1
     @timeit "optimizer" ir = run_passes(opt.src, nargs, opt)
-    force_noinline = _any(@nospecialize(x) -> isexpr(x, :meta) && x.args[1] == :noinline, ir.meta)
+    force_noinline = _any(@nospecialize(x) -> isexpr(x, :meta) && x.args[1] === :noinline, ir.meta)
 
     # compute inlining and other related optimizations
     if (isa(result, Const) || isconstType(result))

base/compiler/ssair/driver.jl

@@ -34,7 +34,7 @@ end
 
 function normalize(@nospecialize(stmt), meta::Vector{Any})
     if isa(stmt, Expr)
-        if stmt.head == :meta
+        if stmt.head === :meta
             args = stmt.args
             if length(args) > 0
                 push!(meta, stmt)

base/compiler/ssair/inlining.jl

@@ -383,7 +383,7 @@ function ir_inline_item!(compact::IncrementalCompact, idx::Int, argexprs::Vector
                 end
             elseif isa(stmt′, GotoNode)
                 stmt′ = GotoNode(stmt′.label + bb_offset)
-            elseif isa(stmt′, Expr) && stmt′.head == :enter
+            elseif isa(stmt′, Expr) && stmt′.head === :enter
                 stmt′ = Expr(:enter, stmt′.args[1] + bb_offset)
             elseif isa(stmt′, GotoIfNot)
                 stmt′ = GotoIfNot(stmt′.cond, stmt′.dest + bb_offset)
@@ -560,7 +560,7 @@ function batch_inline!(todo::Vector{Any}, ir::IRCode, linetable::Vector{LineInfo
                 end
             elseif isa(stmt, GotoNode)
                 compact[idx] = GotoNode(state.bb_rename[stmt.label])
-            elseif isa(stmt, Expr) && stmt.head == :enter
+            elseif isa(stmt, Expr) && stmt.head === :enter
                 compact[idx] = Expr(:enter, state.bb_rename[stmt.args[1]])
             elseif isa(stmt, GotoIfNot)
                 compact[idx] = GotoIfNot(stmt.cond, state.bb_rename[stmt.dest])

base/compiler/ssair/ir.jl

@@ -80,7 +80,7 @@ function basic_blocks_starts(stmts::Vector{Any})
             if stmt.head === :leave
                 # :leave terminates a BB
                 push!(jump_dests, idx+1)
-            elseif stmt.head == :enter
+            elseif stmt.head === :enter
                 # :enter starts/ends a BB
                 push!(jump_dests, idx)
                 push!(jump_dests, idx+1)
@@ -151,7 +151,7 @@ function compute_basic_blocks(stmts::Vector{Any})
                 push!(b.succs, block′)
             end
         elseif isa(terminator, Expr)
-            if terminator.head == :enter
+            if terminator.head === :enter
                 # :enter gets a virtual edge to the exception handler and
                 # the exception handler gets a virtual edge from outside
                 # the function.
@@ -162,7 +162,7 @@ function compute_basic_blocks(stmts::Vector{Any})
                 push!(blocks[block′].preds, num)
                 push!(blocks[block′].preds, 0)
                 push!(b.succs, block′)
-            elseif terminator.head == :gotoifnot
+            elseif terminator.head === :gotoifnot
                 block′ = block_for_inst(basic_block_index, terminator.args[2]::Int)
                 if block′ == num + 1
                     # This GotoIfNot acts like a noop - treat it as such.

base/compiler/ssair/legacy.jl

@@ -35,7 +35,7 @@ function inflate_ir(ci::CodeInfo, sptypes::Vector{Any}, argtypes::Vector{Any})
             code[i] = GotoIfNot(stmt.cond, block_for_inst(cfg, stmt.dest))
         elseif isa(stmt, PhiNode)
             code[i] = PhiNode(Any[block_for_inst(cfg, edge) for edge in stmt.edges], stmt.values)
-        elseif isa(stmt, Expr) && stmt.head == :enter
+        elseif isa(stmt, Expr) && stmt.head === :enter
             stmt.args[1] = block_for_inst(cfg, stmt.args[1])
             code[i] = stmt
         else
@@ -87,7 +87,7 @@ function replace_code_newstyle!(ci::CodeInfo, ir::IRCode, nargs::Int)
             else
                 ci.code[i] = Expr(:unreachable)
             end
-        elseif isa(stmt, Expr) && stmt.head == :enter
+        elseif isa(stmt, Expr) && stmt.head === :enter
             stmt.args[1] = first(ir.cfg.blocks[stmt.args[1]].stmts)
             ci.code[i] = stmt
         else

base/compiler/ssair/passes.jl

@@ -571,7 +571,7 @@ function getfield_elim_pass!(ir::IRCode, domtree::DomTree)
             (isa(c1, Const) && isa(c2, Const)) && continue
             lift_comparison!(compact, idx, c1, c2, stmt, lifting_cache)
             continue
-        elseif isexpr(stmt, :call) && stmt.args[1] == :unchecked_getfield
+        elseif isexpr(stmt, :call) && stmt.args[1] === :unchecked_getfield
             is_getfield = true
             is_unchecked = true
         elseif isexpr(stmt, :foreigncall)

base/compiler/ssair/slot2ssa.jl

@@ -475,7 +475,7 @@ function domsort_ssa!(ir::IRCode, domtree::DomTree)
             end
             result_stmts[inst_range[end]] = GotoIfNot(terminator.cond, bb_rename[terminator.dest])
         elseif !isa(terminator, ReturnNode)
-            if isa(terminator, Expr) && terminator.head == :enter
+            if isa(terminator, Expr) && terminator.head === :enter
                 terminator.args[1] = bb_rename[terminator.args[1]]
             end
             if bb_rename[bb + 1] != new_bb + 1

base/compiler/validation.jl

@@ -139,9 +139,9 @@ function validate_code!(errors::Vector{>:InvalidCodeError}, c::CodeInfo, is_top_
                     push!(errors, InvalidCodeError(INVALID_RETURN, x.args[1]))
                 end
                 validate_val!(x.args[1])
-            elseif head === :call || head === :invoke || head == :gc_preserve_end || head === :meta ||
+            elseif head === :call || head === :invoke || head === :gc_preserve_end || head === :meta ||
                 head === :inbounds || head === :foreigncall || head === :cfunction ||
-                head === :const || head === :enter || head === :leave || head == :pop_exception ||
+                head === :const || head === :enter || head === :leave || head === :pop_exception ||
                 head === :method || head === :global || head === :static_parameter ||
                 head === :new || head === :splatnew || head === :thunk || head === :loopinfo ||
                 head === :throw_undef_if_not || head === :unreachable

base/deprecated.jl

@@ -42,16 +42,16 @@ macro deprecate(old, new, ex=true)
                   depwarn($"`$old` is deprecated, use `$new` instead.", Core.Typeof($(esc(old))).name.mt.name)
                   $(esc(new))(args...)
               end))
-    elseif isa(old, Expr) && (old.head == :call || old.head == :where)
+    elseif isa(old, Expr) && (old.head === :call || old.head === :where)
         remove_linenums!(new)
         oldcall = sprint(show_unquoted, old)
         newcall = sprint(show_unquoted, new)
         # if old.head is a :where, step down one level to the :call to avoid code duplication below
-        callexpr = old.head == :call ? old : old.args[1]
-        if callexpr.head == :call
+        callexpr = old.head === :call ? old : old.args[1]
+        if callexpr.head === :call
             if isa(callexpr.args[1], Symbol)
                 oldsym = callexpr.args[1]::Symbol
-            elseif isa(callexpr.args[1], Expr) && callexpr.args[1].head == :curly
+            elseif isa(callexpr.args[1], Expr) && callexpr.args[1].head === :curly
                 oldsym = callexpr.args[1].args[1]::Symbol
             else
                 error("invalid usage of @deprecate")

base/fastmath.jl

@@ -91,7 +91,7 @@ const rewrite_op =
 function make_fastmath(expr::Expr)
     if expr.head === :quote
         return expr
-    elseif expr.head == :call && expr.args[1] == :^ && expr.args[3] isa Integer
+    elseif expr.head === :call && expr.args[1] === :^ && expr.args[3] isa Integer
         # mimic Julia's literal_pow lowering of literal integer powers
         return Expr(:call, :(Base.FastMath.pow_fast), make_fastmath(expr.args[2]), Val{expr.args[3]}())
     end

base/floatfuncs.jl

@@ -313,7 +313,7 @@ fma_llvm(x::Float64, y::Float64, z::Float64) = fma_float(x, y, z)
 # 1.0000000009313226 = 1 + 1/2^30
 # If fma_llvm() clobbers the rounding mode, the result of 0.1 + 0.2 will be 0.3
 # instead of the properly-rounded 0.30000000000000004; check after calling fma
-if (Sys.ARCH != :i686 && fma_llvm(1.0000305f0, 1.0000305f0, -1.0f0) == 6.103609f-5 &&
+if (Sys.ARCH !== :i686 && fma_llvm(1.0000305f0, 1.0000305f0, -1.0f0) == 6.103609f-5 &&
     (fma_llvm(1.0000000009313226, 1.0000000009313226, -1.0) ==
      1.8626451500983188e-9) && 0.1 + 0.2 == 0.30000000000000004)
     fma(x::Float32, y::Float32, z::Float32) = fma_llvm(x,y,z)