diff --git a/NEWS.md b/NEWS.md
index 7ef91ecf65efe..c6462b408de58 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -34,6 +34,10 @@ New language features
 Library improvements
 --------------------
 
+  * `convert(Ptr{T1}, x::Array{T2})` is now deprecated unless `T1 == T2`
+    or `T1 == None` ([#6073]).  (You can still explicitly `convert`
+    one pointer type into another if needed.)
+
   * Well-behaved floating-point ranges ([#2333], [#5636]).
     Introduced the `FloatRange` type for floating-point ranges with a step,
     which will give intuitive/correct results for classically problematic
diff --git a/base/deprecated.jl b/base/deprecated.jl
index ed39c6229bd11..a2165ab4dc88c 100644
--- a/base/deprecated.jl
+++ b/base/deprecated.jl
@@ -12,9 +12,16 @@ macro deprecate(old,new)
     elseif isa(old,Expr) && old.head == :call
         oldcall = sprint(io->show_unquoted(io,old))
         newcall = sprint(io->show_unquoted(io,new))
-        oldname = Expr(:quote, old.args[1])
+        oldsym = if isa(old.args[1],Symbol)
+            old.args[1]
+        elseif isa(old.args[1],Expr) && old.args[1].head == :curly
+            old.args[1].args[1]
+        else
+            error("invalid usage of @deprecate")
+        end
+        oldname = Expr(:quote, oldsym)
         Expr(:toplevel,
-            Expr(:export,esc(old.args[1])),
+            Expr(:export,esc(oldsym)),
             :($(esc(old)) = begin
                   depwarn(string($oldcall," is deprecated, use ",$newcall," instead."),
                           $oldname)
@@ -402,6 +409,8 @@ Set{T<:Number}(xs::T...) = Set{T}(xs)
 
 @deprecate normfro(A) vecnorm(A)
 
+@deprecate convert{T}(p::Type{Ptr{T}}, a::Array) convert(p, pointer(a))
+
 # 0.3 discontinued functions
 
 function nnz(X)
diff --git a/base/linalg/cholmod.jl b/base/linalg/cholmod.jl
index ce797bd5989b0..5dcc61dfeae1e 100644
--- a/base/linalg/cholmod.jl
+++ b/base/linalg/cholmod.jl
@@ -86,7 +86,7 @@ end
 ### These offsets should be reconfigured to be less error-prone in matches
 const chm_com_offsets = Array(Int, length(ChmCommon.types))
 ccall((:jl_cholmod_common_offsets, :libsuitesparse_wrapper),
-      Void, (Ptr{Uint8},), chm_com_offsets)
+      Void, (Ptr{Int},), chm_com_offsets)
 const chm_final_ll_inds = (1:4) + chm_com_offsets[7]
 const chm_prt_inds = (1:4) + chm_com_offsets[13]
 const chm_ityp_inds = (1:4) + chm_com_offsets[18]
diff --git a/base/linalg/lapack.jl b/base/linalg/lapack.jl
index 1a542f17b5111..5f5d4653b53ed 100644
--- a/base/linalg/lapack.jl
+++ b/base/linalg/lapack.jl
@@ -1027,7 +1027,7 @@ for (geev, gesvd, gesdd, ggsvd, elty, relty) in
                 if cmplx
                     ccall(($(string(gesdd)),liblapack), Void,
                           (Ptr{BlasChar}, Ptr{BlasInt}, Ptr{BlasInt}, Ptr{$elty},
-                           Ptr{BlasInt}, Ptr{$elty}, Ptr{$elty}, Ptr{BlasInt},
+                           Ptr{BlasInt}, Ptr{$relty}, Ptr{$elty}, Ptr{BlasInt},
                            Ptr{$elty}, Ptr{BlasInt}, Ptr{$elty}, Ptr{BlasInt},
                            Ptr{$relty}, Ptr{BlasInt}, Ptr{BlasInt}),
                           &job, &m, &n, A, &max(1,stride(A,2)), S, U, &max(1,stride(U,2)), VT, &max(1,stride(VT,2)),
@@ -2070,7 +2070,7 @@ for (trcon, trevc, trrfs, elty, relty) in
             @chkuplo
             rcond = Array($relty, 1)
             work  = Array($elty, 2n)
-            rwork = Array($elty, n)
+            rwork = Array($relty, n)
             info  = Array(BlasInt, 1)
             ccall(($(string(trcon)),liblapack), Void,
                   (Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasInt},
@@ -2150,7 +2150,7 @@ for (trcon, trevc, trrfs, elty, relty) in
             nrhs=size(B,2)
             nrhs==size(X,2) || throw(DimensionMismatch(""))
             work=Array($elty, 2n)
-            rwork=Array($elty, n)
+            rwork=Array($relty, n)
             info=Array(BlasInt, 1)
             ccall(($(string(trrfs)),liblapack), Void,
                 (Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasInt}, 
@@ -2987,7 +2987,7 @@ for (syev, syevr, sygvd, elty, relty) in
                     (Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasChar}, Ptr{BlasInt}, 
                         Ptr{$elty}, Ptr{BlasInt}, Ptr{$elty}, Ptr{$elty}, 
                         Ptr{BlasInt}, Ptr{BlasInt}, Ptr{$elty}, Ptr{BlasInt},
-                        Ptr{$elty}, Ptr{$elty}, Ptr{BlasInt}, Ptr{BlasInt},
+                        Ptr{$relty}, Ptr{$elty}, Ptr{BlasInt}, Ptr{BlasInt},
                         Ptr{$elty}, Ptr{BlasInt}, Ptr{$relty}, Ptr{BlasInt},
                             Ptr{BlasInt}, Ptr{BlasInt}, Ptr{BlasInt}),
                         &jobz, &range, &uplo, &n, 
diff --git a/base/pointer.jl b/base/pointer.jl
index 3e2debbaca24c..1c52dec7bb173 100644
--- a/base/pointer.jl
+++ b/base/pointer.jl
@@ -16,10 +16,12 @@ convert{T}(::Type{Ptr{T}}, p::Ptr) = box(Ptr{T}, unbox(Ptr,p))
 # object to pointer
 convert(::Type{Ptr{Uint8}}, x::Symbol) = ccall(:jl_symbol_name, Ptr{Uint8}, (Any,), x)
 convert(::Type{Ptr{Int8}}, x::Symbol) = ccall(:jl_symbol_name, Ptr{Int8}, (Any,), x)
-convert{T}(::Type{Ptr{T}}, a::Array) = ccall(:jl_array_ptr, Ptr{T}, (Any,), a)
 convert(::Type{Ptr{Uint8}}, s::ByteString) = convert(Ptr{Uint8}, s.data)
 convert(::Type{Ptr{Int8}}, s::ByteString) = convert(Ptr{Int8}, s.data)
 
+convert{T}(::Type{Ptr{T}}, a::Array{T}) = ccall(:jl_array_ptr, Ptr{T}, (Any,), a)
+convert(::Type{Ptr{None}}, a::Array) = ccall(:jl_array_ptr, Ptr{None}, (Any,), a)
+
 pointer{T}(::Type{T}, x::Uint) = convert(Ptr{T}, x)
 pointer{T}(::Type{T}, x::Ptr) = convert(Ptr{T}, x)
 # note: these definitions don't mean any AbstractArray is convertible to
diff --git a/doc/manual/calling-c-and-fortran-code.rst b/doc/manual/calling-c-and-fortran-code.rst
index ff5cb1b494f1f..77664853f96f6 100644
--- a/doc/manual/calling-c-and-fortran-code.rst
+++ b/doc/manual/calling-c-and-fortran-code.rst
@@ -192,16 +192,20 @@ When a scalar value is passed with ``&`` as an argument of type
 Array conversions
 ~~~~~~~~~~~~~~~~~
 
-When an ``Array`` is passed to C as a ``Ptr`` argument, it is
-"converted" simply by taking the address of the first element. This is
-done in order to avoid copying arrays unnecessarily, and to tolerate the
-slight mismatches in pointer types that are often encountered in C APIs
-(for example, passing a ``Float64`` array to a function that operates on
-uninterpreted bytes).
+When an ``Array{T}`` is passed to C as a ``Ptr{T}`` or ``Ptr{Void}``
+argument, it is "converted" simply by taking the address of the first
+element. This is done in order to avoid copying arrays unnecessarily.
 
 Therefore, if an ``Array`` contains data in the wrong format, it will
 have to be explicitly converted using a call such as ``int32(a)``.
 
+To pass an array ``A`` as a pointer of a different type *without*
+converting the data (for example, to pass a ``Float64`` array to a
+function that operates on uninterpreted bytes), you can either declare
+the argument as ``Ptr{Void}`` or you can explicitly call
+``convert(Ptr{T}, pointer(A))``.
+
+
 Type correspondences
 ~~~~~~~~~~~~~~~~~~~~