error hint for getproperty(::Dict, ::Symbol)

base/boot.jl

@@ -206,7 +206,7 @@ export
     InterruptException, InexactError, OutOfMemoryError, ReadOnlyMemoryError,
     OverflowError, StackOverflowError, SegmentationFault, UndefRefError, UndefVarError,
     TypeError, ArgumentError, MethodError, AssertionError, LoadError, InitError,
-    UndefKeywordError, ConcurrencyViolationError,
+    UndefKeywordError, ConcurrencyViolationError, FieldError,
     # AST representation
     Expr, QuoteNode, LineNumberNode, GlobalRef,
     # object model functions
@@ -404,6 +404,11 @@ struct AssertionError <: Exception
 end
 AssertionError() = AssertionError("")
 
+struct FieldError <: Exception
+    type::DataType
+    field::Symbol
+end
+
 abstract type WrappedException <: Exception end
 
 struct LoadError <: WrappedException

base/errorshow.jl

@@ -367,6 +367,12 @@ function showerror(io::IO, ex::MethodError)
     nothing
 end
 
+function showerror(io::IO, exc::FieldError)
+    @nospecialize
+    print(io, "FieldError: type $(exc.type |> nameof) has no field $(exc.field)")
+    Base.Experimental.show_error_hints(io, exc)
+end
+
 striptype(::Type{T}) where {T} = T
 striptype(::Any) = nothing
 
@@ -1086,6 +1092,31 @@ end
 
 Experimental.register_error_hint(methods_on_iterable, MethodError)
 
+# Display a hint in case the user tries to access non-member fields of container type datastructures
+function fielderror_hint_handler(io, exc)
+    @nospecialize
+    field = exc.field
+    type = exc.type
+    if type <: Dict
+        println(io,
+            """
+            \nDid you mean to access dict values using key: `:$field` ?
+            Consider using indexing syntax.
+
+            # Example
+            julia> dict = Dict(:$(field)=>5)
+            Dict{Symbol, Int64} with 1 entry:
+              :$(field) => 5
+
+            julia> dict[:$(field)]
+            5
+            """
+        )
+    end
+end
+
+Experimental.register_error_hint(fielderror_hint_handler, FieldError)
+
 # ExceptionStack implementation
 size(s::ExceptionStack) = size(s.stack)
 getindex(s::ExceptionStack, i::Int) = s.stack[i]

base/reflection.jl

@@ -976,7 +976,7 @@ julia> struct Foo
        end
 
 julia> Base.fieldindex(Foo, :z)
-ERROR: type Foo has no field z
+ERROR: FieldError: type Foo has no field z
 Stacktrace:
 [...]
 

src/codegen.cpp

@@ -4080,7 +4080,7 @@ static jl_llvm_functions_t
         jl_value_t *rettype,
         jl_codegen_params_t &params);
 
-static void emit_hasnofield_error_ifnot(jl_codectx_t &ctx, Value *ok, jl_sym_t *type, jl_cgval_t name);
+static void emit_hasnofield_error_ifnot(jl_codectx_t &ctx, Value *ok, jl_datatype_t *type, jl_cgval_t name);
 
 static bool emit_builtin_call(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
                               ArrayRef<jl_cgval_t> argv, size_t nargs, jl_value_t *rt,
@@ -4590,15 +4590,15 @@ static bool emit_builtin_call(jl_codectx_t &ctx, jl_cgval_t *ret, jl_value_t *f,
                     assert(jl_svec_len(fn) == 1);
                     Value *typ_sym = literal_pointer_val(ctx, jl_svecref(fn, 0));
                     Value *cond = ctx.builder.CreateICmpEQ(mark_callee_rooted(ctx, typ_sym), mark_callee_rooted(ctx, boxed(ctx, fld)));
-                    emit_hasnofield_error_ifnot(ctx, cond, utt->name->name, fld);
+                    emit_hasnofield_error_ifnot(ctx, cond, utt, fld);
                     *ret = emit_getfield_knownidx(ctx, obj, 0, utt, order);
                     return true;
                 }
                 else {
                     Value *index = ctx.builder.CreateCall(prepare_call(jlfieldindex_func),
                             {emit_typeof(ctx, obj, false, false), boxed(ctx, fld), ConstantInt::get(getInt32Ty(ctx.builder.getContext()), 0)});
                     Value *cond = ctx.builder.CreateICmpNE(index, ConstantInt::get(getInt32Ty(ctx.builder.getContext()), -1));
-                    emit_hasnofield_error_ifnot(ctx, cond, utt->name->name, fld);
+                    emit_hasnofield_error_ifnot(ctx, cond, utt, fld);
                     Value *idx2 = ctx.builder.CreateAdd(ctx.builder.CreateIntCast(index, ctx.types().T_size, false), ConstantInt::get(ctx.types().T_size, 1)); // getfield_unknown is 1 based
                     if (emit_getfield_unknownidx(ctx, ret, obj, idx2, utt, jl_false, order))
                         return true;
@@ -5429,7 +5429,7 @@ static jl_cgval_t emit_call(jl_codectx_t &ctx, jl_expr_t *ex, jl_value_t *rt, bo
 
 // --- accessing and assigning variables ---
 
-static void emit_hasnofield_error_ifnot(jl_codectx_t &ctx, Value *ok, jl_sym_t *type, jl_cgval_t name)
+static void emit_hasnofield_error_ifnot(jl_codectx_t &ctx, Value *ok, jl_datatype_t *type, jl_cgval_t name)
 {
     ++EmittedUndefVarErrors;
     assert(name.typ == (jl_value_t*)jl_symbol_type);

src/datatype.c

@@ -1736,7 +1736,7 @@ JL_DLLEXPORT int jl_field_index(jl_datatype_t *t, jl_sym_t *fld, int err)
         }
     }
     if (err)
-        jl_has_no_field_error(t->name->name, fld);
+        jl_has_no_field_error(t, fld);
     return -1;
 }
 

src/jl_exported_data.inc

@@ -138,6 +138,7 @@
     XX(jl_uint8_type) \
     XX(jl_undefref_exception) \
     XX(jl_undefvarerror_type) \
+    XX(jl_fielderror_type) \
     XX(jl_unionall_type) \
     XX(jl_uniontype_type) \
     XX(jl_upsilonnode_type) \

src/jltypes.c

@@ -3727,6 +3727,7 @@ void post_boot_hooks(void)
     jl_diverror_exception  = jl_new_struct_uninit((jl_datatype_t*)core("DivideError"));
     jl_undefref_exception  = jl_new_struct_uninit((jl_datatype_t*)core("UndefRefError"));
     jl_undefvarerror_type  = (jl_datatype_t*)core("UndefVarError");
+    jl_fielderror_type     = (jl_datatype_t*)core("FieldError");
     jl_atomicerror_type    = (jl_datatype_t*)core("ConcurrencyViolationError");
     jl_interrupt_exception = jl_new_struct_uninit((jl_datatype_t*)core("InterruptException"));
     jl_boundserror_type    = (jl_datatype_t*)core("BoundsError");

src/julia.h

@@ -869,6 +869,7 @@ extern JL_DLLIMPORT jl_datatype_t *jl_initerror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_typeerror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_methoderror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_undefvarerror_type JL_GLOBALLY_ROOTED;
+extern JL_DLLIMPORT jl_datatype_t *jl_fielderror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_atomicerror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_missingcodeerror_type JL_GLOBALLY_ROOTED;
 extern JL_DLLIMPORT jl_datatype_t *jl_lineinfonode_type JL_GLOBALLY_ROOTED;
@@ -2024,7 +2025,7 @@ JL_DLLEXPORT void JL_NORETURN jl_type_error_rt(const char *fname,
                                                jl_value_t *ty JL_MAYBE_UNROOTED,
                                                jl_value_t *got JL_MAYBE_UNROOTED);
 JL_DLLEXPORT void JL_NORETURN jl_undefined_var_error(jl_sym_t *var, jl_value_t *scope JL_MAYBE_UNROOTED);
-JL_DLLEXPORT void JL_NORETURN jl_has_no_field_error(jl_sym_t *type_name, jl_sym_t *var);
+JL_DLLEXPORT void JL_NORETURN jl_has_no_field_error(jl_datatype_t *t, jl_sym_t *var);
 JL_DLLEXPORT void JL_NORETURN jl_atomic_error(char *str);
 JL_DLLEXPORT void JL_NORETURN jl_bounds_error(jl_value_t *v JL_MAYBE_UNROOTED,
                                               jl_value_t *t JL_MAYBE_UNROOTED);

src/rtutils.c

@@ -152,9 +152,9 @@ JL_DLLEXPORT void JL_NORETURN jl_undefined_var_error(jl_sym_t *var, jl_value_t *
     jl_throw(jl_new_struct(jl_undefvarerror_type, var, scope));
 }
 
-JL_DLLEXPORT void JL_NORETURN jl_has_no_field_error(jl_sym_t *type_name, jl_sym_t *var)
+JL_DLLEXPORT void JL_NORETURN jl_has_no_field_error(jl_datatype_t *t, jl_sym_t *var)
 {
-    jl_errorf("type %s has no field %s", jl_symbol_name(type_name), jl_symbol_name(var));
+    jl_throw(jl_new_struct(jl_fielderror_type, t, var));
 }
 
 JL_DLLEXPORT void JL_NORETURN jl_atomic_error(char *str) // == jl_exceptionf(jl_atomicerror_type, "%s", str)

src/staticdata.c

@@ -100,7 +100,7 @@ extern "C" {
 // TODO: put WeakRefs on the weak_refs list during deserialization
 // TODO: handle finalizers
 
-#define NUM_TAGS    190
+#define NUM_TAGS    191
 
 // An array of references that need to be restored from the sysimg
 // This is a manually constructed dual of the gvars array, which would be produced by codegen for Julia code, for C.
@@ -235,6 +235,7 @@ jl_value_t **const*const get_tags(void) {
         INSERT_TAG(jl_loaderror_type);
         INSERT_TAG(jl_initerror_type);
         INSERT_TAG(jl_undefvarerror_type);
+        INSERT_TAG(jl_fielderror_type);
         INSERT_TAG(jl_stackovf_exception);
         INSERT_TAG(jl_diverror_exception);
         INSERT_TAG(jl_interrupt_exception);

stdlib/LinearAlgebra/test/bunchkaufman.jl

@@ -114,7 +114,7 @@ bimint = rand(1:5, n, 2)
                 bc1 = bunchkaufman(Symmetric(asym, uplo))
                 @test getproperty(bc1, uplo)*bc1.D*transpose(getproperty(bc1, uplo)) ≈ asym[bc1.p, bc1.p]
                 @test getproperty(bc1, uplo)*bc1.D*transpose(getproperty(bc1, uplo)) ≈ bc1.P*asym*transpose(bc1.P)
-                @test_throws ErrorException bc1.Z
+                @test_throws FieldError bc1.Z
                 @test_throws ArgumentError uplo === :L ? bc1.U : bc1.L
             end
             # test Base.iterate

stdlib/LinearAlgebra/test/cholesky.jl

@@ -17,7 +17,7 @@ function unary_ops_tests(a, ca, tol; n=size(a, 1))
     @test logabsdet_ca[1] ≈ logabsdet_a[1]
     @test logabsdet_ca[2] ≈ logabsdet_a[2]
     @test isposdef(ca)
-    @test_throws ErrorException ca.Z
+    @test_throws FieldError ca.Z
     @test size(ca) == size(a)
     @test Array(copy(ca)) ≈ a
     @test tr(ca) ≈ tr(a) skip=ca isa CholeskyPivoted

stdlib/LinearAlgebra/test/eigen.jl

@@ -80,7 +80,7 @@ aimg  = randn(n,n)/2
             @test eigvecs(asym_sg, ASG2) == f.vectors
             @test eigvals(f) === f.values
             @test eigvecs(f) === f.vectors
-            @test_throws ErrorException f.Z
+            @test_throws FieldError f.Z
 
             d,v = eigen(asym_sg, ASG2)
             @test d == f.values
@@ -141,7 +141,7 @@ aimg  = randn(n,n)/2
             @test f.values ≈ eigvals(a1_nsg, a2_nsg; sortby = sortfunc)
             @test prod(f.values) ≈ prod(eigvals(a1_nsg/a2_nsg, sortby = sortfunc)) atol=50000ε
             @test eigvecs(a1_nsg, a2_nsg; sortby = sortfunc) == f.vectors
-            @test_throws ErrorException f.Z
+            @test_throws FieldError f.Z
 
             g = eigen(a1_nsg, Diagonal(1:n1))
             @test a1_nsg*g.vectors ≈ (Diagonal(1:n1)*g.vectors) * Diagonal(g.values)

stdlib/LinearAlgebra/test/hessenberg.jl

@@ -148,7 +148,7 @@ let n = 10
         @test size(H.Q, 2) == size(A, 2)
         @test size(H.Q) == size(A)
         @test size(H) == size(A)
-        @test_throws ErrorException H.Z
+        @test_throws FieldError H.Z
         @test convert(Array, H) ≈ A
         @test (H.Q * H.H) * H.Q' ≈ A ≈ (Matrix(H.Q) * Matrix(H.H)) * Matrix(H.Q)'
         @test (H.Q' * A) * H.Q ≈ H.H

stdlib/LinearAlgebra/test/lq.jl

@@ -50,7 +50,7 @@ rectangularQ(Q::LinearAlgebra.LQPackedQ) = convert(Array, Q)
                     for (ii, lq_obj) in enumerate(lqa)
                         @test ref_obs[ii] == lq_obj
                     end
-                    @test_throws ErrorException lqa.Z
+                    @test_throws FieldError lqa.Z
                     @test Array(copy(adjoint(lqa))) ≈ a'
                     @test q*squareQ(q)' ≈ Matrix(I, n, n)
                     @test l*q ≈ a

stdlib/LinearAlgebra/test/lu.jl

@@ -59,7 +59,7 @@ dimg  = randn(n)/2
     κ  = cond(a,1)
     @testset "(Automatic) Square LU decomposition" begin
         lua   = factorize(a)
-        @test_throws ErrorException lua.Z
+        @test_throws FieldError lua.Z
         l,u,p = lua.L, lua.U, lua.p
         ll,ul,pl = @inferred lu(a)
         @test ll * ul ≈ a[pl,:]
@@ -88,7 +88,7 @@ dimg  = randn(n)/2
         lud = @inferred lu(d)
         @test LinearAlgebra.issuccess(lud)
         @test @inferred(lu(lud)) == lud
-        @test_throws ErrorException lud.Z
+        @test_throws FieldError lud.Z
         @test lud.L*lud.U ≈ lud.P*Array(d)
         @test lud.L*lud.U ≈ Array(d)[lud.p,:]
         @test AbstractArray(lud) ≈ d

stdlib/LinearAlgebra/test/qr.jl

@@ -50,7 +50,7 @@ rectangularQ(Q::LinearAlgebra.AbstractQ) = Matrix(Q)
             @testset "QR decomposition (without pivoting)" begin
                 qra   = @inferred qr(a)
                 q, r  = qra.Q, qra.R
-                @test_throws ErrorException qra.Z
+                @test_throws FieldError qra.Z
                 @test q'*squareQ(q) ≈ Matrix(I, a_1, a_1)
                 @test q*squareQ(q)' ≈ Matrix(I, a_1, a_1)
                 @test q'*Matrix(1.0I, a_1, a_1)' ≈ squareQ(q)'
@@ -79,7 +79,7 @@ rectangularQ(Q::LinearAlgebra.AbstractQ) = Matrix(Q)
             @testset "Thin QR decomposition (without pivoting)" begin
                 qra   = @inferred qr(a[:, 1:n1], NoPivot())
                 q,r   = qra.Q, qra.R
-                @test_throws ErrorException qra.Z
+                @test_throws FieldError qra.Z
                 @test q'*squareQ(q) ≈ Matrix(I, a_1, a_1)
                 @test q'*rectangularQ(q) ≈ Matrix(I, a_1, n1)
                 @test q*r ≈ a[:, 1:n1]
@@ -106,7 +106,7 @@ rectangularQ(Q::LinearAlgebra.AbstractQ) = Matrix(Q)
 
                 qrpa  = factorize(a[1:n1,:])
                 q,r = qrpa.Q, qrpa.R
-                @test_throws ErrorException qrpa.Z
+                @test_throws FieldError qrpa.Z
                 p = qrpa.p
                 @test q'*squareQ(q) ≈ Matrix(I, n1, n1)
                 @test q*squareQ(q)' ≈ Matrix(I, n1, n1)
@@ -134,7 +134,7 @@ rectangularQ(Q::LinearAlgebra.AbstractQ) = Matrix(Q)
             @testset "(Automatic) Thin (pivoted) QR decomposition" begin
                 qrpa  = factorize(a[:,1:n1])
                 q,r = qrpa.Q, qrpa.R
-                @test_throws ErrorException qrpa.Z
+                @test_throws FieldError qrpa.Z
                 p = qrpa.p
                 @test q'*squareQ(q) ≈ Matrix(I, a_1, a_1)
                 @test q*squareQ(q)' ≈ Matrix(I, a_1, a_1)

stdlib/LinearAlgebra/test/schur.jl

@@ -33,7 +33,7 @@ aimg  = randn(n,n)/2
         @test sort(imag(f.values)) ≈ sort(imag(d))
         @test istriu(f.Schur) || eltype(a)<:Real
         @test convert(Array, f) ≈ a
-        @test_throws ErrorException f.A
+        @test_throws FieldError f.A
 
         sch, vecs, vals = schur(UpperTriangular(triu(a)))
         @test vecs*sch*vecs' ≈ triu(a)
@@ -68,7 +68,7 @@ aimg  = randn(n,n)/2
             O = ordschur(S, select)
             sum(select) != 0 && @test S.values[findall(select)] ≈ O.values[1:sum(select)]
             @test O.vectors*O.Schur*O.vectors' ≈ ordschura
-            @test_throws ErrorException f.A
+            @test_throws FieldError f.A
             Snew = LinearAlgebra.Schur(S.T, S.Z, S.values)
             SchurNew = ordschur!(copy(Snew), select)
             @test O.vectors ≈ SchurNew.vectors
@@ -88,7 +88,7 @@ aimg  = randn(n,n)/2
             @test f.Q*f.T*f.Z' ≈ a2_sf
             @test istriu(f.S) || eltype(a)<:Real
             @test istriu(f.T) || eltype(a)<:Real
-            @test_throws ErrorException f.A
+            @test_throws FieldError f.A
 
             sstring = sprint((t, s) -> show(t, "text/plain", s), f.S)
             tstring = sprint((t, s) -> show(t, "text/plain", s), f.T)

stdlib/LinearAlgebra/test/svd.jl

@@ -75,7 +75,7 @@ aimg  = randn(n,n)/2
             @test usv.U * (Diagonal(usv.S) * usv.Vt) ≈ a
             @test convert(Array, usv) ≈ a
             @test usv.Vt' ≈ usv.V
-            @test_throws ErrorException usv.Z
+            @test_throws FieldError usv.Z
             b = rand(eltya,n)
             @test usv\b ≈ a\b
             @test Base.propertynames(usv) == (:U, :S, :V, :Vt)
@@ -94,7 +94,7 @@ aimg  = randn(n,n)/2
                 @test usv.U * (Diagonal(usv.S) * usv.Vt) ≈ transform(a)
                 @test convert(Array, usv) ≈ transform(a)
                 @test usv.Vt' ≈ usv.V
-                @test_throws ErrorException usv.Z
+                @test_throws FieldError usv.Z
                 b = rand(eltya,n)
                 @test usv\b ≈ transform(a)\b
             end
@@ -106,8 +106,8 @@ aimg  = randn(n,n)/2
             @test gsvd.U*gsvd.D1*gsvd.R*gsvd.Q' ≈ a
             @test gsvd.V*gsvd.D2*gsvd.R*gsvd.Q' ≈ a_svd
             @test usv.Vt' ≈ usv.V
-            @test_throws ErrorException usv.Z
-            @test_throws ErrorException gsvd.Z
+            @test_throws FieldError usv.Z
+            @test_throws FieldError gsvd.Z
             @test gsvd.vals ≈ svdvals(a,a_svd)
             α = eltya == Int ? -1 : rand(eltya)
             β = svd(α)
@@ -148,7 +148,7 @@ aimg  = randn(n,n)/2
             @test usv.U * (Diagonal(usv.S) * usv.Vt) ≈ T(asym)
             @test convert(Array, usv) ≈ T(asym)
             @test usv.Vt' ≈ usv.V
-            @test_throws ErrorException usv.Z
+            @test_throws FieldError usv.Z
             b = rand(eltya,n)
             @test usv\b ≈ T(asym)\b
         end

test/compiler/codegen.jl

@@ -859,7 +859,7 @@ foo50964(1) # Shouldn't assert!
 
 # https://github.com/JuliaLang/julia/issues/51233
 obj51233 = (1,)
-@test_throws ErrorException obj51233.x
+@test_throws FieldError obj51233.x
 
 # Very specific test for multiversioning
 if Sys.ARCH === :x86_64

test/compiler/inference.jl

@@ -479,7 +479,7 @@ end
 @test f15259(1,2) == (1,2,1,2)
 # check that error cases are still correct
 @eval g15259(x,y) = (a = $(Expr(:new, :A15259, :x, :y)); a.z)
-@test_throws ErrorException g15259(1,1)
+@test_throws FieldError g15259(1,1)
 @eval h15259(x,y) = (a = $(Expr(:new, :A15259, :x, :y)); getfield(a, 3))
 @test_throws BoundsError h15259(1,1)
 

test/core.jl

@@ -1924,9 +1924,9 @@ end
 
 # issue #4526
 f4526(x) = isa(x.a, Nothing)
-@test_throws ErrorException f4526(1)
-@test_throws ErrorException f4526(im)
-@test_throws ErrorException f4526(1+2im)
+@test_throws FieldError f4526(1)
+@test_throws FieldError f4526(im)
+@test_throws FieldError f4526(1+2im)
 
 # issue #4528
 function f4528(A, B)