diff --git a/bootstrap/command.go b/bootstrap/command.go
index 636dcb0..cc55b28 100644
--- a/bootstrap/command.go
+++ b/bootstrap/command.go
@@ -22,6 +22,7 @@
 	"os"
 	"path/filepath"
 	"runtime"
+	"runtime/debug"
 	"runtime/pprof"
 	"runtime/trace"
 
@@ -34,8 +35,10 @@
 	depFile    string
 	docFile    string
 	cpuprofile string
+	memprofile string
 	traceFile  string
 	runGoTests bool
+	noGC       bool
 
 	BuildDir string
 	SrcDir   string
@@ -48,6 +51,8 @@
 	flag.StringVar(&docFile, "docs", "", "build documentation file to output")
 	flag.StringVar(&cpuprofile, "cpuprofile", "", "write cpu profile to file")
 	flag.StringVar(&traceFile, "trace", "", "write trace to file")
+	flag.StringVar(&memprofile, "memprofile", "", "write memory profile to file")
+	flag.BoolVar(&noGC, "nogc", false, "turn off GC for debugging")
 	flag.BoolVar(&runGoTests, "t", false, "build and run go tests during bootstrap")
 }
 
@@ -58,6 +63,10 @@
 
 	runtime.GOMAXPROCS(runtime.NumCPU())
 
+	if noGC {
+		debug.SetGCPercent(-1)
+	}
+
 	if cpuprofile != "" {
 		f, err := os.Create(cpuprofile)
 		if err != nil {
@@ -160,6 +169,15 @@
 			fatalf("error removing abandoned files: %s", err)
 		}
 	}
+
+	if memprofile != "" {
+		f, err := os.Create(memprofile)
+		if err != nil {
+			fatalf("error opening memprofile: %s", err)
+		}
+		defer f.Close()
+		pprof.WriteHeapProfile(f)
+	}
 }
 
 func fatalf(format string, args ...interface{}) {
@@ -174,7 +192,9 @@
 
 	for _, err := range errs {
 		switch err := err.(type) {
-		case *blueprint.Error:
+		case *blueprint.BlueprintError,
+			*blueprint.ModuleError,
+			*blueprint.PropertyError:
 			fmt.Printf("%serror:%s %s\n", red, unred, err.Error())
 		default:
 			fmt.Printf("%sinternal error:%s %s\n", red, unred, err)
diff --git a/context.go b/context.go
index 7ab28f9..c59b107 100644
--- a/context.go
+++ b/context.go
@@ -105,11 +105,37 @@
 
 // An Error describes a problem that was encountered that is related to a
 // particular location in a Blueprints file.
-type Error struct {
+type BlueprintError struct {
 	Err error            // the error that occurred
 	Pos scanner.Position // the relevant Blueprints file location
 }
 
+// A ModuleError describes a problem that was encountered that is related to a
+// particular module in a Blueprints file
+type ModuleError struct {
+	BlueprintError
+	module *moduleInfo
+}
+
+// A PropertyError describes a problem that was encountered that is related to a
+// particular property in a Blueprints file
+type PropertyError struct {
+	ModuleError
+	property string
+}
+
+func (e *BlueprintError) Error() string {
+	return fmt.Sprintf("%s: %s", e.Pos, e.Err)
+}
+
+func (e *ModuleError) Error() string {
+	return fmt.Sprintf("%s: %s: %s", e.Pos, e.module, e.Err)
+}
+
+func (e *PropertyError) Error() string {
+	return fmt.Sprintf("%s: %s: %s: %s", e.Pos, e.module, e.property, e.Err)
+}
+
 type localBuildActions struct {
 	variables []*localVariable
 	rules     []*localRule
@@ -229,11 +255,6 @@
 	parallel        bool
 }
 
-func (e *Error) Error() string {
-
-	return fmt.Sprintf("%s: %s", e.Pos, e.Err)
-}
-
 // NewContext creates a new Context object.  The created context initially has
 // no module or singleton factories registered, so the RegisterModuleFactory and
 // RegisterSingletonFactory methods must be called before it can do anything
@@ -514,7 +535,7 @@
 	if len(errs) > 0 {
 		for i, err := range errs {
 			if parseErr, ok := err.(*parser.ParseError); ok {
-				err = &Error{
+				err = &BlueprintError{
 					Err: parseErr.Err,
 					Pos: parseErr.Pos,
 				}
@@ -787,7 +808,7 @@
 		globPattern := filepath.Join(dir, file)
 		matches, matchedDirs, err := pathtools.Glob(globPattern)
 		if err != nil {
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("%q: %s", globPattern, err.Error()),
 				Pos: buildPos,
 			})
@@ -795,7 +816,7 @@
 		}
 
 		if len(matches) == 0 {
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("%q: not found", globPattern),
 				Pos: buildPos,
 			})
@@ -809,12 +830,12 @@
 			if err != nil {
 				errs = append(errs, err)
 			} else if !exists {
-				errs = append(errs, &Error{
+				errs = append(errs, &BlueprintError{
 					Err: fmt.Errorf("%q not found", foundBlueprints),
 				})
 				continue
 			} else if dir {
-				errs = append(errs, &Error{
+				errs = append(errs, &BlueprintError{
 					Err: fmt.Errorf("%q is a directory", foundBlueprints),
 				})
 				continue
@@ -835,7 +856,7 @@
 		globPattern := filepath.Join(dir, subdir)
 		matches, matchedDirs, err := pathtools.Glob(globPattern)
 		if err != nil {
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("%q: %s", globPattern, err.Error()),
 				Pos: subdirsPos,
 			})
@@ -843,7 +864,7 @@
 		}
 
 		if len(matches) == 0 && !optional {
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("%q: not found", globPattern),
 				Pos: subdirsPos,
 			})
@@ -916,7 +937,7 @@
 
 			return ret, assignment.EqualsPos, nil
 		case *parser.Bool, *parser.String:
-			return nil, scanner.Position{}, &Error{
+			return nil, scanner.Position{}, &BlueprintError{
 				Err: fmt.Errorf("%q must be a list of strings", v),
 				Pos: assignment.EqualsPos,
 			}
@@ -934,7 +955,7 @@
 		case *parser.String:
 			return value.Value, assignment.EqualsPos, nil
 		case *parser.Bool, *parser.List:
-			return "", scanner.Position{}, &Error{
+			return "", scanner.Position{}, &BlueprintError{
 				Err: fmt.Errorf("%q must be a string", v),
 				Pos: assignment.EqualsPos,
 			}
@@ -1050,7 +1071,7 @@
 				}
 			}
 			if newDep == nil {
-				errs = append(errs, &Error{
+				errs = append(errs, &BlueprintError{
 					Err: fmt.Errorf("failed to find variation %q for module %q needed by %q",
 						variationName, dep.module.properties.Name, module.properties.Name),
 					Pos: module.pos,
@@ -1085,7 +1106,7 @@
 		}
 
 		return nil, []error{
-			&Error{
+			&BlueprintError{
 				Err: fmt.Errorf("unrecognized module type %q", moduleDef.Type),
 				Pos: moduleDef.TypePos,
 			},
@@ -1126,11 +1147,11 @@
 
 	if group, present := c.moduleGroups[name]; present {
 		return []error{
-			&Error{
+			&BlueprintError{
 				Err: fmt.Errorf("module %q already defined", name),
 				Pos: module.pos,
 			},
-			&Error{
+			&BlueprintError{
 				Err: fmt.Errorf("<-- previous definition here"),
 				Pos: group.modules[0].pos,
 			},
@@ -1223,7 +1244,7 @@
 
 func (c *Context) addDependency(module *moduleInfo, tag DependencyTag, depName string) []error {
 	if depName == module.properties.Name {
-		return []error{&Error{
+		return []error{&BlueprintError{
 			Err: fmt.Errorf("%q depends on itself", depName),
 			Pos: module.pos,
 		}}
@@ -1235,7 +1256,7 @@
 			module.missingDeps = append(module.missingDeps, depName)
 			return nil
 		}
-		return []error{&Error{
+		return []error{&BlueprintError{
 			Err: fmt.Errorf("%q depends on undefined module %q",
 				module.properties.Name, depName),
 			Pos: module.pos,
@@ -1254,7 +1275,7 @@
 		return nil
 	}
 
-	return []error{&Error{
+	return []error{&BlueprintError{
 		Err: fmt.Errorf("dependency %q of %q missing variant %q",
 			depGroup.modules[0].properties.Name, module.properties.Name,
 			c.prettyPrintVariant(module.dependencyVariant)),
@@ -1264,7 +1285,7 @@
 
 func (c *Context) findReverseDependency(module *moduleInfo, destName string) (*moduleInfo, []error) {
 	if destName == module.properties.Name {
-		return nil, []error{&Error{
+		return nil, []error{&BlueprintError{
 			Err: fmt.Errorf("%q depends on itself", destName),
 			Pos: module.pos,
 		}}
@@ -1272,7 +1293,7 @@
 
 	destInfo, ok := c.moduleGroups[destName]
 	if !ok {
-		return nil, []error{&Error{
+		return nil, []error{&BlueprintError{
 			Err: fmt.Errorf("%q has a reverse dependency on undefined module %q",
 				module.properties.Name, destName),
 			Pos: module.pos,
@@ -1283,7 +1304,7 @@
 		return m, nil
 	}
 
-	return nil, []error{&Error{
+	return nil, []error{&BlueprintError{
 		Err: fmt.Errorf("reverse dependency %q of %q missing variant %q",
 			destName, module.properties.Name,
 			c.prettyPrintVariant(module.dependencyVariant)),
@@ -1300,7 +1321,7 @@
 			module.missingDeps = append(module.missingDeps, depName)
 			return nil
 		}
-		return []error{&Error{
+		return []error{&BlueprintError{
 			Err: fmt.Errorf("%q depends on undefined module %q",
 				module.properties.Name, depName),
 			Pos: module.pos,
@@ -1329,7 +1350,7 @@
 		}
 		if found {
 			if module == m {
-				return []error{&Error{
+				return []error{&BlueprintError{
 					Err: fmt.Errorf("%q depends on itself", depName),
 					Pos: module.pos,
 				}}
@@ -1338,7 +1359,7 @@
 			// that module is earlier in the module list than this one, since we always
 			// run GenerateBuildActions in order for the variants of a module
 			if depGroup == module.group && beforeInModuleList(module, m, module.group.modules) {
-				return []error{&Error{
+				return []error{&BlueprintError{
 					Err: fmt.Errorf("%q depends on later version of itself", depName),
 					Pos: module.pos,
 				}}
@@ -1349,7 +1370,7 @@
 		}
 	}
 
-	return []error{&Error{
+	return []error{&BlueprintError{
 		Err: fmt.Errorf("dependency %q of %q missing variant %q",
 			depGroup.modules[0].properties.Name, module.properties.Name,
 			c.prettyPrintVariant(newVariant)),
@@ -1498,7 +1519,7 @@
 		// for generating the errors.  The cycle list is in
 		// reverse order because all the 'check' calls append
 		// their own module to the list.
-		errs = append(errs, &Error{
+		errs = append(errs, &BlueprintError{
 			Err: fmt.Errorf("encountered dependency cycle:"),
 			Pos: cycle[len(cycle)-1].pos,
 		})
@@ -1507,7 +1528,7 @@
 		curModule := cycle[0]
 		for i := len(cycle) - 1; i >= 0; i-- {
 			nextModule := cycle[i]
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("    %q depends on %q",
 					curModule.properties.Name,
 					nextModule.properties.Name),
@@ -1975,7 +1996,7 @@
 		if module.missingDeps != nil && !mctx.handledMissingDeps {
 			var errs []error
 			for _, depName := range module.missingDeps {
-				errs = append(errs, &Error{
+				errs = append(errs, &BlueprintError{
 					Err: fmt.Errorf("%q depends on undefined module %q",
 						module.properties.Name, depName),
 					Pos: module.pos,
@@ -2446,7 +2467,7 @@
 	args ...interface{}) error {
 
 	module := c.moduleInfo[logicModule]
-	return &Error{
+	return &BlueprintError{
 		Err: fmt.Errorf(format, args...),
 		Pos: module.pos,
 	}
diff --git a/module_ctx.go b/module_ctx.go
index 88bb7eb..22896c2 100644
--- a/module_ctx.go
+++ b/module_ctx.go
@@ -193,7 +193,7 @@
 func (d *baseModuleContext) Errorf(pos scanner.Position,
 	format string, args ...interface{}) {
 
-	d.error(&Error{
+	d.error(&BlueprintError{
 		Err: fmt.Errorf(format, args...),
 		Pos: pos,
 	})
@@ -202,9 +202,12 @@
 func (d *baseModuleContext) ModuleErrorf(format string,
 	args ...interface{}) {
 
-	d.error(&Error{
-		Err: fmt.Errorf(format, args...),
-		Pos: d.module.pos,
+	d.error(&ModuleError{
+		BlueprintError: BlueprintError{
+			Err: fmt.Errorf(format, args...),
+			Pos: d.module.pos,
+		},
+		module: d.module,
 	})
 }
 
@@ -217,11 +220,15 @@
 		pos = d.module.pos
 	}
 
-	format = property + ": " + format
-
-	d.error(&Error{
-		Err: fmt.Errorf(format, args...),
-		Pos: pos,
+	d.error(&PropertyError{
+		ModuleError: ModuleError{
+			BlueprintError: BlueprintError{
+				Err: fmt.Errorf(format, args...),
+				Pos: pos,
+			},
+			module: d.module,
+		},
+		property: property,
 	})
 }
 
@@ -248,9 +255,12 @@
 	args ...interface{}) {
 
 	module := m.context.moduleInfo[logicModule]
-	m.errs = append(m.errs, &Error{
-		Err: fmt.Errorf(format, args...),
-		Pos: module.pos,
+	m.errs = append(m.errs, &ModuleError{
+		BlueprintError: BlueprintError{
+			Err: fmt.Errorf(format, args...),
+			Pos: module.pos,
+		},
+		module: module,
 	})
 }
 
diff --git a/unpack.go b/unpack.go
index babaf07..48d5105 100644
--- a/unpack.go
+++ b/unpack.go
@@ -63,7 +63,7 @@
 	for name, packedProperty := range propertyMap {
 		result[name] = packedProperty.property
 		if !packedProperty.unpacked {
-			err := &Error{
+			err := &BlueprintError{
 				Err: fmt.Errorf("unrecognized property %q", name),
 				Pos: packedProperty.property.ColonPos,
 			}
@@ -88,11 +88,11 @@
 				// We've already added this property.
 				continue
 			}
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("property %q already defined", name),
 				Pos: propertyDef.ColonPos,
 			})
-			errs = append(errs, &Error{
+			errs = append(errs, &BlueprintError{
 				Err: fmt.Errorf("<-- previous definition here"),
 				Pos: first.property.ColonPos,
 			})
@@ -216,7 +216,7 @@
 
 		if proptools.HasTag(field, "blueprint", "mutated") {
 			errs = append(errs,
-				&Error{
+				&BlueprintError{
 					Err: fmt.Errorf("mutated field %s cannot be set in a Blueprint file", propertyName),
 					Pos: packedProperty.property.ColonPos,
 				})
@@ -228,7 +228,7 @@
 
 		if filterKey != "" && !proptools.HasTag(field, filterKey, filterValue) {
 			errs = append(errs,
-				&Error{
+				&BlueprintError{
 					Err: fmt.Errorf("filtered field %s cannot be set in a Blueprint file", propertyName),
 					Pos: packedProperty.property.ColonPos,
 				})
diff --git a/unpack_test.go b/unpack_test.go
index ea4dbc7..f470356 100644
--- a/unpack_test.go
+++ b/unpack_test.go
@@ -244,7 +244,7 @@
 			},
 		},
 		errs: []error{
-			&Error{
+			&BlueprintError{
 				Err: fmt.Errorf("filtered field nested.foo cannot be set in a Blueprint file"),
 				Pos: mkpos(30, 4, 9),
 			},