diff --git a/base/complex.jl b/base/complex.jl
index 9bbfe8d98f76e..50b6253e25540 100644
--- a/base/complex.jl
+++ b/base/complex.jl
@@ -27,7 +27,6 @@ convert{T<:Real}(::Type{Complex{T}}, z::Complex) =
 convert{T<:Real}(::Type{T}, z::Complex) = (imag(z)==0 ? convert(T,real(z)) :
                                            throw(InexactError()))
 
-promote_rule{T<:Real}(::Type{Complex{T}}, ::Type{T}) = Complex{T}
 promote_rule{T<:Real,S<:Real}(::Type{Complex{T}}, ::Type{S}) =
     Complex{promote_type(T,S)}
 promote_rule{T<:Real,S<:Real}(::Type{Complex{T}}, ::Type{Complex{S}}) =
diff --git a/base/rational.jl b/base/rational.jl
index 5e17dcb898076..b27b4910fea19 100644
--- a/base/rational.jl
+++ b/base/rational.jl
@@ -53,7 +53,6 @@ end
 convert(::Type{Rational}, x::Float64) = convert(Rational{Int64}, x)
 convert(::Type{Rational}, x::Float32) = convert(Rational{Int}, x)
 
-promote_rule{T<:Integer}(::Type{Rational{T}}, ::Type{T}) = Rational{T}
 promote_rule{T<:Integer,S<:Integer}(::Type{Rational{T}}, ::Type{S}) = Rational{promote_type(T,S)}
 promote_rule{T<:Integer,S<:Integer}(::Type{Rational{T}}, ::Type{Rational{S}}) = Rational{promote_type(T,S)}
 promote_rule{T<:Integer,S<:FloatingPoint}(::Type{Rational{T}}, ::Type{S}) = promote_type(T,S)
diff --git a/base/string.jl b/base/string.jl
index b6512c467edc2..ca46faaf0a354 100644
--- a/base/string.jl
+++ b/base/string.jl
@@ -814,13 +814,7 @@ end
 
 ## string promotion rules ##
 
-promote_rule(::Type{UTF8String} , ::Type{ASCIIString}) = UTF8String
-promote_rule(::Type{UTF8String} , ::Type{UTF16String}) = UTF8String
-promote_rule(::Type{ASCIIString}, ::Type{UTF16String}) = UTF8String
-promote_rule(::Type{UTF32String}, ::Type{UTF16String}) = UTF8String
-promote_rule(::Type{UTF8String} , ::Type{UTF32String}) = UTF8String
-promote_rule(::Type{ASCIIString}, ::Type{UTF32String}) = UTF8String
-promote_rule{T<:String}(::Type{RepString}, ::Type{T}) = RepString
+promote_rule{S<:String,T<:String}(::Type{S}, ::Type{T}) = UTF8String
 
 ## printing literal quoted string data ##