look up constructors by type name in depwarn. fixes JuliaLang#21972

Author: JeffBezanson

base/deprecated.jl

@@ -96,6 +96,15 @@ function firstcaller(bt::Array{Ptr{Void},1}, funcsyms)
             end
             found && @goto found
             found = lkup.func in funcsyms
+            # look for constructor type name
+            if !found && !isnull(lkup.linfo)
+                li = get(lkup.linfo)
+                ft = ccall(:jl_first_argument_datatype, Any, (Any,), li.def.sig)
+                if isa(ft,DataType) && ft.name === Type.body.name
+                    ft = unwrap_unionall(ft.parameters[1])
+                    found = (isa(ft,DataType) && ft.name.name in funcsyms)
+                end
+            end
         end
     end
     return StackTraces.UNKNOWN

test/misc.jl

@@ -779,6 +779,14 @@ module Foo1234
     foo1234(x) = x+1
 end
 
+# issue #21972
+struct T21972
+    @noinline function T21972()
+        Base.depwarn("something", :T21972)
+        new()
+    end
+end
+
 @testset "@deprecate" begin
     using .DeprecationTests
     using .Foo1234
@@ -805,6 +813,13 @@ end
 
     # @test @test_warn "A{T}(x::S) where {T, S} is deprecated, use f() instead." A{Int}(1.)
     # @test @test_nowarn A{Int}(1.)
+
+    # issue #21972
+    @noinline function f21972()
+        T21972()
+    end
+    @test_warn "deprecated" f21972()
+    @test_nowarn f21972()
 end
 
 @testset "inline bug #18735" begin