diff --git a/base/c.jl b/base/c.jl
index fdcc405b3146d..5b7f6bb0efa7d 100644
--- a/base/c.jl
+++ b/base/c.jl
@@ -639,7 +639,7 @@ function ccall_macro_parse(expr::Expr)
 end
 
 
-function ccall_macro_lower(convention, func, rettype, types, args, nreq)
+function ccall_macro_lower(convention, effects, func, rettype, types, args, nreq)
     lowering = []
     realargs = []
     gcroots = []
@@ -676,7 +676,7 @@ function ccall_macro_lower(convention, func, rettype, types, args, nreq)
                esc(etypes),
                nreq,
                QuoteNode(convention),
-               nothing,
+               effects,
                realargs..., gcroots...)
     push!(lowering, exp)
 
@@ -732,5 +732,9 @@ The string literal could also be used directly before the function
 name, if desired `"libglib-2.0".g_uri_escape_string(...`
 """
 macro ccall(expr)
-    return ccall_macro_lower(:ccall, ccall_macro_parse(expr)...)
+    return ccall_macro_lower(:ccall, nothing, ccall_macro_parse(expr)...)
+end
+
+macro ccall_effects(effects, expr)
+    return ccall_macro_lower(:ccall, effects, ccall_macro_parse(expr)...)
 end
diff --git a/base/compiler/types.jl b/base/compiler/types.jl
index fffe23b687d92..50a387bc2d080 100644
--- a/base/compiler/types.jl
+++ b/base/compiler/types.jl
@@ -68,9 +68,9 @@ function encode_effects_override(eo::EffectsOverride)
     e = 0x00
     eo.consistent && (e |= 0x01)
     eo.effect_free && (e |= 0x02)
-    eo.nothrow && (e |= 0x02)
-    eo.terminates && (e |= 0x04)
-    eo.terminates_locally && (e |= 0x08)
+    eo.nothrow && (e |= 0x04)
+    eo.terminates && (e |= 0x08)
+    eo.terminates_locally && (e |= 0x10)
     e
 end
 
@@ -82,7 +82,6 @@ decode_effects_override(e::UInt8) =
         (e >> 3) & 0x01 != 0x00,
         (e >> 4) & 0x01 != 0x00)
 
-
 """
     InferenceResult
 
diff --git a/base/expr.jl b/base/expr.jl
index f3a694960aa3e..dfd36f3e877e3 100644
--- a/base/expr.jl
+++ b/base/expr.jl
@@ -520,7 +520,14 @@ macro assume_effects(args...)
         end
     end
     ex = args[end]
-    isa(ex, Expr) || ArgumentError("Bad expression `$ex` in @constprop [settings] ex")
+    isa(ex, Expr) || throw(ArgumentError("Bad expression `$ex` in @constprop [settings] ex"))
+    if ex.head === :macrocall && ex.args[1] == Symbol("@ccall")
+        ex.args[1] = GlobalRef(Base, Symbol("@ccall_effects"))
+        insert!(ex.args, 3, Core.Compiler.encode_effects_override(Core.Compiler.EffectsOverride(
+            consistent, effect_free, nothrow, terminates_globally, terminates_locally
+        )))
+        return esc(ex)
+    end
     return pushmeta!(ex, :purity, consistent, effect_free, nothrow, terminates_globally, terminates_locally)
 end
 
diff --git a/test/ccall.jl b/test/ccall.jl
index 55942d8310d82..f2ac071557de4 100644
--- a/test/ccall.jl
+++ b/test/ccall.jl
@@ -36,7 +36,7 @@ end
         Core.svec(Ptr{Ptr{Cchar}}, Cstring,
             UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8, UInt8,
             Cfloat, Cfloat, Cfloat, Cfloat, Cfloat, Cfloat, Cfloat, Cfloat, Cfloat),
-            2, :(:cdecl),
+            2, :(:cdecl), nothing,
             :(Base.unsafe_convert(Ptr{Ptr{Cchar}}, strp)), :(Base.unsafe_convert(Cstring, fmt)),
             0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0x7, 0x8, 0x9, 0xa, 0xb, 0xc, 0xd, 0xe, 0xf,
             Cfloat(1.1), Cfloat(2.2), Cfloat(3.3), Cfloat(4.4), Cfloat(5.5), Cfloat(6.6), Cfloat(7.7), Cfloat(8.8), Cfloat(9.9),
@@ -1676,7 +1676,7 @@ using Base: ccall_macro_parse, ccall_macro_lower
 end
 
 @testset "ensure the base-case of @ccall works, including library name and pointer interpolation" begin
-    call = ccall_macro_lower(:ccall, ccall_macro_parse( :( libstring.func(
+    call = ccall_macro_lower(:ccall, nothing, ccall_macro_parse( :( libstring.func(
         str::Cstring,
         num1::Cint,
         num2::Cint
@@ -1700,7 +1700,7 @@ end
         end)
 
     # pointer interpolation
-    call = ccall_macro_lower(:ccall, ccall_macro_parse(:( $(Expr(:$, :fptr))("bar"::Cstring)::Cvoid ))...)
+    call = ccall_macro_lower(:ccall, nothing, ccall_macro_parse(:( $(Expr(:$, :fptr))("bar"::Cstring)::Cvoid ))...)
     @test Base.remove_linenums!(call) == Base.remove_linenums!(
     quote
         func = $(Expr(:escape, :fptr))
@@ -1852,3 +1852,9 @@ end
     @test cglobal33413_literal() != C_NULL
     @test cglobal33413_literal_notype() != C_NULL
 end
+
+@testset "ccall_effects" begin
+    ctest_total(x) = @Base.assume_effects :total @ccall libccalltest.ctest(x::Complex{Int})::Complex{Int}
+    ctest_total_const() = Val{ctest_total(1 + 2im)}()
+    Core.Compiler.return_type(ctest_total_const, Tuple{}) == Val{2 + 0im}
+end