diff --git a/src/cmd/compile/internal/gc/main.go b/src/cmd/compile/internal/gc/main.go
index 339e8e08cd..09378bab6e 100644
--- a/src/cmd/compile/internal/gc/main.go
+++ b/src/cmd/compile/internal/gc/main.go
@@ -480,7 +480,7 @@ func Main(archInit func(*Arch)) {
 
 	// Process top-level declarations in phases.
 
-	// Phase 1: const, type, and names and types of funcs.
+	// Phase 1: type, and names and types of funcs.
 	//   This will gather all the information about types
 	//   and methods but doesn't depend on any of it.
 	defercheckwidth()
@@ -489,16 +489,29 @@ func Main(archInit func(*Arch)) {
 	timings.Start("fe", "typecheck", "top1")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
-		if op := n.Op; op != ODCL && op != OAS && op != OAS2 {
+		if op := n.Op; op != ODCL && op != OAS && op != OAS2 && op != ODCLCONST {
 			xtop[i] = typecheck(n, Etop)
 		}
 	}
 
-	// Phase 2: Variable assignments.
-	//   To check interface assignments, depends on phase 1.
+	// Phase 2: Constant declarations.
+	//   To have named types fully type checked, depends on phase 1.
 
 	// Don't use range--typecheck can add closures to xtop.
 	timings.Start("fe", "typecheck", "top2")
+	for i := 0; i < len(xtop); i++ {
+		n := xtop[i]
+		if op := n.Op; op == ODCLCONST {
+			xtop[i] = typecheck(n, Etop)
+		}
+	}
+
+	// Phase 3: Variable assignments.
+	//   To check interface assignments, depends on phase 1.
+	//   To use constants, depends on phase 2.
+
+	// Don't use range--typecheck can add closures to xtop.
+	timings.Start("fe", "typecheck", "top3")
 	for i := 0; i < len(xtop); i++ {
 		n := xtop[i]
 		if op := n.Op; op == ODCL || op == OAS || op == OAS2 {
diff --git a/test/fixedbugs/issue24755.go b/test/fixedbugs/issue24755.go
new file mode 100644
index 0000000000..07c9d5a418
--- /dev/null
+++ b/test/fixedbugs/issue24755.go
@@ -0,0 +1,16 @@
+// errorcheck
+
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Tests that all types and functions are type-checked before any constant
+// declaration is. Issue #24755.
+package p
+
+type I interface{ F() }
+type T struct{}
+
+const _ = I(T{}) // ERROR "const initializer I\(T literal\) is not a constant"
+
+func (T) F() {}