diff --git a/pkg/corset/resolver.go b/pkg/corset/resolver.go
index 98c255c..56de1d6 100644
--- a/pkg/corset/resolver.go
+++ b/pkg/corset/resolver.go
@@ -23,14 +23,16 @@ func ResolveCircuit(srcmap *sexp.SourceMaps[Node], circuit *Circuit) (*GlobalSco
 	}
 	// Construct resolver
 	r := resolver{srcmap}
-	// Allocate declared input columns
-	errs := r.resolveDeclarations(scope, circuit)
+	// Initialise all columns
+	errs1 := r.initialiseDeclarations(scope, circuit)
+	// Finalise all columns / declarations
+	errs2 := r.resolveDeclarations(scope, circuit)
 	//
-	if len(errs) > 0 {
-		return nil, errs
+	if len(errs1)+len(errs2) > 0 {
+		return nil, append(errs1, errs2...)
 	}
 	// Done
-	return scope, errs
+	return scope, nil
 }
 
 // Resolver packages up information necessary for resolving a circuit and
@@ -42,6 +44,22 @@ type resolver struct {
 	srcmap *sexp.SourceMaps[Node]
 }
 
+// Initialise all columns from their declaring constructs.
+func (r *resolver) initialiseDeclarations(scope *GlobalScope, circuit *Circuit) []SyntaxError {
+	// Input columns must be allocated before assignemts, since the hir.Schema
+	// separates these out.
+	errs := r.initialiseDeclarationsInModule(scope.Module(""), circuit.Declarations)
+	//
+	for _, m := range circuit.Modules {
+		// Process all declarations in the module
+		merrs := r.initialiseDeclarationsInModule(scope.Module(m.Name), m.Declarations)
+		// Package up all errors
+		errs = append(errs, merrs...)
+	}
+	//
+	return errs
+}
+
 // Process all assignment column declarations.  These are more complex than for
 // input columns, since there can be dependencies between them.  Thus, we cannot
 // simply resolve them in one linear scan.
@@ -65,10 +83,6 @@ func (r *resolver) resolveDeclarations(scope *GlobalScope, circuit *Circuit) []S
 // to process all columns before we can sure that they are all declared
 // correctly.
 func (r *resolver) resolveDeclarationsInModule(scope *ModuleScope, decls []Declaration) []SyntaxError {
-	// Columns & Assignments
-	if errors := r.initialiseDeclarationsInModule(scope, decls); len(errors) > 0 {
-		return errors
-	}
 	// Aliases
 	if errors := r.initialiseAliasesInModule(scope, decls); len(errors) > 0 {
 		return errors
diff --git a/pkg/test/valid_corset_test.go b/pkg/test/valid_corset_test.go
index 73e6f3e..fa84f49 100644
--- a/pkg/test/valid_corset_test.go
+++ b/pkg/test/valid_corset_test.go
@@ -588,6 +588,10 @@ func Test_Lookup_08(t *testing.T) {
 	Check(t, false, "lookup_08")
 }
 
+func Test_Lookup_09(t *testing.T) {
+	Check(t, false, "lookup_09")
+}
+
 // ===================================================================
 // Interleaving
 // ===================================================================
diff --git a/testdata/constant_invalid_10.lisp b/testdata/constant_invalid_10.lisp
index 480027e..e131979 100644
--- a/testdata/constant_invalid_10.lisp
+++ b/testdata/constant_invalid_10.lisp
@@ -1,4 +1,7 @@
-;;error:9:13-14:symbol X already declared
+;;error:12:13-14:symbol X already declared
+;;error:13:22-37:expected loobean constraint (found 𝔽)
+;;error:14:22-45:expected loobean constraint (found 𝔽)
+;;error:15:22-46:expected loobean constraint (found 𝔽)
 (defconst
   X     1
   ONE   X
diff --git a/testdata/lookup_09.accepts b/testdata/lookup_09.accepts
new file mode 100644
index 0000000..1e5d955
--- /dev/null
+++ b/testdata/lookup_09.accepts
@@ -0,0 +1,175 @@
+;; { "X": [], "m1.A": [] }
+;; { "X": [0], "m1.A": [0] }
+;; Check initial padding row!
+{ "X": [0], "m1.A": [1] }
+;;
+{ "X": [0,0], "m1.A": [0,0] }
+{ "X": [0,0], "m1.A": [0,1] }
+{ "X": [0,0], "m1.A": [1,0] }
+{ "X": [1,0], "m1.A": [0,1] }
+{ "X": [1,0], "m1.A": [1,0] }
+{ "X": [1,0], "m1.A": [1,1] }
+{ "X": [0,1], "m1.A": [0,1] }
+{ "X": [0,1], "m1.A": [1,0] }
+{ "X": [0,1], "m1.A": [1,1] }
+{ "X": [1,1], "m1.A": [0,1] }
+{ "X": [1,1], "m1.A": [1,0] }
+{ "X": [1,1], "m1.A": [1,1] }
+{ "X": [1,1], "m1.A": [1,2] }
+{ "X": [2,2], "m1.A": [2,2] }
+{ "X": [2,2], "m1.A": [2,1] }
+{ "X": [2,2], "m1.A": [1,2] }
+{ "X": [1,2], "m1.A": [2,1] }
+{ "X": [1,2], "m1.A": [1,2] }
+{ "X": [2,1], "m1.A": [2,1] }
+{ "X": [2,1], "m1.A": [1,2] }
+{ "X": [1,1], "m1.A": [2,1] }
+{ "X": [1,1], "m1.A": [1,2] }
+{ "X": [1,1], "m1.A": [1,1] }
+;;
+{ "X": [0,0,0], "m1.A": [2,0,1] }
+{ "X": [1,0,0], "m1.A": [2,0,1] }
+{ "X": [0,1,0], "m1.A": [2,0,1] }
+{ "X": [0,0,1], "m1.A": [2,0,1] }
+{ "X": [1,0,1], "m1.A": [2,0,1] }
+{ "X": [0,1,1], "m1.A": [2,0,1] }
+{ "X": [1,1,0], "m1.A": [2,0,1] }
+{ "X": [1,1,1], "m1.A": [2,0,1] }
+{ "X": [0,0,0], "m1.A": [0,2,1] }
+{ "X": [1,0,0], "m1.A": [0,2,1] }
+{ "X": [0,1,0], "m1.A": [0,2,1] }
+{ "X": [0,0,1], "m1.A": [0,2,1] }
+{ "X": [1,0,1], "m1.A": [0,2,1] }
+{ "X": [0,1,1], "m1.A": [0,2,1] }
+{ "X": [1,1,0], "m1.A": [0,2,1] }
+{ "X": [1,1,1], "m1.A": [0,2,1] }
+{ "X": [0,0,0], "m1.A": [0,1,2] }
+{ "X": [1,0,0], "m1.A": [0,1,2] }
+{ "X": [0,1,0], "m1.A": [0,1,2] }
+{ "X": [0,0,1], "m1.A": [0,1,2] }
+{ "X": [1,0,1], "m1.A": [0,1,2] }
+{ "X": [0,1,1], "m1.A": [0,1,2] }
+{ "X": [1,1,0], "m1.A": [0,1,2] }
+{ "X": [1,1,1], "m1.A": [0,1,2] }
+{ "X": [0,0,0], "m1.A": [2,1,0] }
+{ "X": [1,0,0], "m1.A": [2,1,0] }
+{ "X": [0,1,0], "m1.A": [2,1,0] }
+{ "X": [0,0,1], "m1.A": [2,1,0] }
+{ "X": [1,0,1], "m1.A": [2,1,0] }
+{ "X": [0,1,1], "m1.A": [2,1,0] }
+{ "X": [1,1,0], "m1.A": [2,1,0] }
+{ "X": [1,1,1], "m1.A": [2,1,0] }
+{ "X": [0,0,0], "m1.A": [1,2,0] }
+{ "X": [1,0,0], "m1.A": [1,2,0] }
+{ "X": [0,1,0], "m1.A": [1,2,0] }
+{ "X": [0,0,1], "m1.A": [1,2,0] }
+{ "X": [1,0,1], "m1.A": [1,2,0] }
+{ "X": [0,1,1], "m1.A": [1,2,0] }
+{ "X": [1,1,0], "m1.A": [1,2,0] }
+{ "X": [1,1,1], "m1.A": [1,2,0] }
+{ "X": [0,0,0], "m1.A": [1,0,2] }
+{ "X": [1,0,0], "m1.A": [1,0,2] }
+{ "X": [0,1,0], "m1.A": [1,0,2] }
+{ "X": [0,0,1], "m1.A": [1,0,2] }
+{ "X": [1,0,1], "m1.A": [1,0,2] }
+{ "X": [0,1,1], "m1.A": [1,0,2] }
+{ "X": [1,1,0], "m1.A": [1,0,2] }
+{ "X": [1,1,1], "m1.A": [1,0,2] }
+{ "X": [0,0,0], "m1.A": [2,1,1] }
+{ "X": [1,0,0], "m1.A": [2,1,1] }
+{ "X": [0,1,0], "m1.A": [2,1,1] }
+{ "X": [0,0,1], "m1.A": [2,1,1] }
+{ "X": [1,0,1], "m1.A": [2,1,1] }
+{ "X": [0,1,1], "m1.A": [2,1,1] }
+{ "X": [1,1,0], "m1.A": [2,1,1] }
+{ "X": [1,1,1], "m1.A": [2,1,1] }
+{ "X": [0,0,0], "m1.A": [1,2,1] }
+{ "X": [1,0,0], "m1.A": [1,2,1] }
+{ "X": [0,1,0], "m1.A": [1,2,1] }
+{ "X": [0,0,1], "m1.A": [1,2,1] }
+{ "X": [1,0,1], "m1.A": [1,2,1] }
+{ "X": [0,1,1], "m1.A": [1,2,1] }
+{ "X": [1,1,0], "m1.A": [1,2,1] }
+{ "X": [1,1,1], "m1.A": [1,2,1] }
+{ "X": [0,0,0], "m1.A": [1,1,2] }
+{ "X": [1,0,0], "m1.A": [1,1,2] }
+{ "X": [0,1,0], "m1.A": [1,1,2] }
+{ "X": [0,0,1], "m1.A": [1,1,2] }
+{ "X": [1,0,1], "m1.A": [1,1,2] }
+{ "X": [0,1,1], "m1.A": [1,1,2] }
+{ "X": [1,1,0], "m1.A": [1,1,2] }
+{ "X": [1,1,1], "m1.A": [1,1,2] }
+;;
+{ "X": [3,3,3], "m1.A": [2,3,1] }
+{ "X": [1,3,3], "m1.A": [2,3,1] }
+{ "X": [3,1,3], "m1.A": [2,3,1] }
+{ "X": [3,3,1], "m1.A": [2,3,1] }
+{ "X": [1,3,1], "m1.A": [2,3,1] }
+{ "X": [3,1,1], "m1.A": [2,3,1] }
+{ "X": [1,1,3], "m1.A": [2,3,1] }
+{ "X": [1,1,1], "m1.A": [2,3,1] }
+{ "X": [3,3,3], "m1.A": [3,2,1] }
+{ "X": [1,3,3], "m1.A": [3,2,1] }
+{ "X": [3,1,3], "m1.A": [3,2,1] }
+{ "X": [3,3,1], "m1.A": [3,2,1] }
+{ "X": [1,3,1], "m1.A": [3,2,1] }
+{ "X": [3,1,1], "m1.A": [3,2,1] }
+{ "X": [1,1,3], "m1.A": [3,2,1] }
+{ "X": [1,1,1], "m1.A": [3,2,1] }
+{ "X": [3,3,3], "m1.A": [3,1,2] }
+{ "X": [1,3,3], "m1.A": [3,1,2] }
+{ "X": [3,1,3], "m1.A": [3,1,2] }
+{ "X": [3,3,1], "m1.A": [3,1,2] }
+{ "X": [1,3,1], "m1.A": [3,1,2] }
+{ "X": [3,1,1], "m1.A": [3,1,2] }
+{ "X": [1,1,3], "m1.A": [3,1,2] }
+{ "X": [1,1,1], "m1.A": [3,1,2] }
+{ "X": [3,3,3], "m1.A": [2,1,3] }
+{ "X": [1,3,3], "m1.A": [2,1,3] }
+{ "X": [3,1,3], "m1.A": [2,1,3] }
+{ "X": [3,3,1], "m1.A": [2,1,3] }
+{ "X": [1,3,1], "m1.A": [2,1,3] }
+{ "X": [3,1,1], "m1.A": [2,1,3] }
+{ "X": [1,1,3], "m1.A": [2,1,3] }
+{ "X": [1,1,1], "m1.A": [2,1,3] }
+{ "X": [3,3,3], "m1.A": [1,2,3] }
+{ "X": [1,3,3], "m1.A": [1,2,3] }
+{ "X": [3,1,3], "m1.A": [1,2,3] }
+{ "X": [3,3,1], "m1.A": [1,2,3] }
+{ "X": [1,3,1], "m1.A": [1,2,3] }
+{ "X": [3,1,1], "m1.A": [1,2,3] }
+{ "X": [1,1,3], "m1.A": [1,2,3] }
+{ "X": [1,1,1], "m1.A": [1,2,3] }
+{ "X": [3,3,3], "m1.A": [1,3,2] }
+{ "X": [1,3,3], "m1.A": [1,3,2] }
+{ "X": [3,1,3], "m1.A": [1,3,2] }
+{ "X": [3,3,1], "m1.A": [1,3,2] }
+{ "X": [1,3,1], "m1.A": [1,3,2] }
+{ "X": [3,1,1], "m1.A": [1,3,2] }
+{ "X": [1,1,3], "m1.A": [1,3,2] }
+{ "X": [1,1,1], "m1.A": [1,3,2] }
+;;
+{ "X": [3,3,3], "m1.A": [1,2,3] }
+{ "X": [1,3,3], "m1.A": [1,2,3] }
+{ "X": [3,1,3], "m1.A": [1,2,3] }
+{ "X": [3,3,1], "m1.A": [1,2,3] }
+{ "X": [1,3,1], "m1.A": [1,2,3] }
+{ "X": [3,1,1], "m1.A": [1,2,3] }
+{ "X": [1,1,3], "m1.A": [1,2,3] }
+{ "X": [1,1,1], "m1.A": [1,2,3] }
+{ "X": [3,3,3], "m1.A": [2,1,3] }
+{ "X": [1,3,3], "m1.A": [2,1,3] }
+{ "X": [3,1,3], "m1.A": [2,1,3] }
+{ "X": [3,3,1], "m1.A": [2,1,3] }
+{ "X": [1,3,1], "m1.A": [2,1,3] }
+{ "X": [3,1,1], "m1.A": [2,1,3] }
+{ "X": [1,1,3], "m1.A": [2,1,3] }
+{ "X": [1,1,1], "m1.A": [2,1,3] }
+{ "X": [3,3,3], "m1.A": [1,3,2] }
+{ "X": [1,3,3], "m1.A": [1,3,2] }
+{ "X": [3,1,3], "m1.A": [1,3,2] }
+{ "X": [3,3,1], "m1.A": [1,3,2] }
+{ "X": [1,3,1], "m1.A": [1,3,2] }
+{ "X": [3,1,1], "m1.A": [1,3,2] }
+{ "X": [1,1,3], "m1.A": [1,3,2] }
+{ "X": [1,1,1], "m1.A": [1,3,2] }
diff --git a/testdata/lookup_09.lisp b/testdata/lookup_09.lisp
new file mode 100644
index 0000000..39c8244
--- /dev/null
+++ b/testdata/lookup_09.lisp
@@ -0,0 +1,5 @@
+(defcolumns X)
+(deflookup test (m1.A) (X))
+
+(module m1)
+(defcolumns A)
diff --git a/testdata/lookup_09.rejects b/testdata/lookup_09.rejects
new file mode 100644
index 0000000..0e9574f
--- /dev/null
+++ b/testdata/lookup_09.rejects
@@ -0,0 +1,37 @@
+{ "X": [1], "m1.A": [2] }
+;;
+{ "X": [1,2], "m1.A": [1,1] }
+{ "X": [2,1], "m1.A": [1,1] }
+{ "X": [2,2], "m1.A": [1,1] }
+;;
+{ "X": [1,2], "m1.A": [1,3] }
+{ "X": [1,2], "m1.A": [3,1] }
+{ "X": [1,2], "m1.A": [1,1] }
+{ "X": [2,1], "m1.A": [1,1] }
+{ "X": [2,1], "m1.A": [1,3] }
+{ "X": [2,1], "m1.A": [3,1] }
+{ "X": [2,2], "m1.A": [1,3] }
+{ "X": [2,2], "m1.A": [3,1] }
+;;
+{ "X": [3,3,3], "m1.A": [1,2,1] }
+{ "X": [1,3,3], "m1.A": [1,2,1] }
+{ "X": [3,1,3], "m1.A": [1,2,1] }
+{ "X": [3,3,1], "m1.A": [1,2,1] }
+{ "X": [1,3,1], "m1.A": [1,2,1] }
+{ "X": [3,1,1], "m1.A": [1,2,1] }
+{ "X": [1,1,3], "m1.A": [1,2,1] }
+{ "X": [1,1,1], "m1.A": [2,2,2] }
+{ "X": [1,1,1], "m1.A": [2,2,3] }
+{ "X": [1,1,1], "m1.A": [3,2,2] }
+{ "X": [1,1,1], "m1.A": [2,3,2] }
+{ "X": [3,3,3], "m1.A": [1,1,2] }
+{ "X": [1,3,3], "m1.A": [1,1,2] }
+{ "X": [3,1,3], "m1.A": [1,1,2] }
+{ "X": [3,3,1], "m1.A": [1,1,2] }
+{ "X": [1,3,1], "m1.A": [1,1,2] }
+{ "X": [3,1,1], "m1.A": [1,1,2] }
+{ "X": [1,1,3], "m1.A": [1,1,2] }
+{ "X": [1,1,1], "m1.A": [2,2,2] }
+{ "X": [1,1,1], "m1.A": [3,2,2] }
+{ "X": [1,1,1], "m1.A": [2,3,2] }
+{ "X": [1,1,1], "m1.A": [2,2,3] }
diff --git a/testdata/lookup_invalid_06.lisp b/testdata/lookup_invalid_06.lisp
index 33b03d9..ec2eaeb 100644
--- a/testdata/lookup_invalid_06.lisp
+++ b/testdata/lookup_invalid_06.lisp
@@ -1,5 +1,4 @@
-;;error:4:18-22:unknown symbol
-;;error:4:23-27:unknown symbol
+;;error:3:23-27:conflicting context
 (defcolumns X Y)
 (deflookup test (m1.A m2.B) (X Y))
 
diff --git a/testdata/lookup_invalid_07.lisp b/testdata/lookup_invalid_07.lisp
index 5330cdc..6dfc8f7 100644
--- a/testdata/lookup_invalid_07.lisp
+++ b/testdata/lookup_invalid_07.lisp
@@ -1,5 +1,4 @@
-;;error:4:21-25:unknown symbol
-;;error:4:26-30:unknown symbol
+;;error:3:26-30:conflicting context
 (defcolumns X)
 (deflookup test ((+ m1.A m2.B)) (X))