diff --git a/extractor/dbscheme/tables.go b/extractor/dbscheme/tables.go
index 7fdb08f610c..6bda018e8a4 100644
--- a/extractor/dbscheme/tables.go
+++ b/extractor/dbscheme/tables.go
@@ -786,6 +786,12 @@ var FieldStructsTable = NewTable("fieldstructs",
 	EntityColumn(StructType, "struct"),
 )
 
+// MethodHostsTable maps interface methods to the named type they belong to
+var MethodHostsTable = NewTable("methodhosts",
+	EntityColumn(ObjectType, "method").Unique(),
+	EntityColumn(NamedType, "host"),
+)
+
 // DefsTable maps identifiers to the objects they define
 var DefsTable = NewTable("defs",
 	EntityColumn(IdentExpr, "ident"),
diff --git a/extractor/extractor.go b/extractor/extractor.go
index 78cdbab67cf..c1169044000 100644
--- a/extractor/extractor.go
+++ b/extractor/extractor.go
@@ -1096,7 +1096,8 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 		case *types.Named:
 			kind = dbscheme.NamedType.Index()
 			dbscheme.TypeNameTable.Emit(tw, lbl, tp.Obj().Name())
-			extractUnderlyingType(tw, lbl, tp.Underlying())
+			underlying := tp.Underlying()
+			extractUnderlyingType(tw, lbl, underlying)
 
 			entitylbl, exists := tw.Labeler.LookupObjectID(tp.Obj(), lbl)
 			if entitylbl == trap.InvalidLabel {
@@ -1119,6 +1120,19 @@ func extractType(tw *trap.Writer, tp types.Type) trap.Label {
 					extractObject(tw, meth, methlbl)
 				}
 			}
+
+			// associate all methods of underlying interface with this type
+			if underlyingInterface, ok := underlying.(*types.Interface); ok {
+				underlyingInterfaceLabel, _ := getTypeLabel(tw, underlyingInterface)
+				for i := 0; i < underlyingInterface.NumMethods(); i++ {
+					meth := underlyingInterface.Method(i)
+					methlbl, exists := tw.Labeler.MethodID(underlyingInterface.Method(i), underlyingInterfaceLabel)
+					if !exists {
+						log.Printf("No label for method %s of type %s yet.", meth.Name(), tp.Obj().Name())
+					}
+					dbscheme.MethodHostsTable.Emit(tw, methlbl, lbl)
+				}
+			}
 		default:
 			log.Fatalf("unexpected type %T", tp)
 		}
diff --git a/ql/src/go.dbscheme b/ql/src/go.dbscheme
index ffced433fce..391ab3ba573 100644
--- a/ql/src/go.dbscheme
+++ b/ql/src/go.dbscheme
@@ -89,6 +89,8 @@ methodreceivers(unique int method: @object ref, int receiver: @object ref);
 
 fieldstructs(unique int field: @object ref, int struct: @structtype ref);
 
+methodhosts(unique int method: @object ref, int host: @namedtype ref);
+
 defs(int ident: @ident ref, int object: @object ref);
 
 uses(int ident: @ident ref, int object: @object ref);
diff --git a/ql/src/go.dbscheme.stats b/ql/src/go.dbscheme.stats
index d0d559d148b..74eefcc8e27 100644
--- a/ql/src/go.dbscheme.stats
+++ b/ql/src/go.dbscheme.stats
@@ -466,7 +466,7 @@
 </e>
 <e>
 <k>@declvarobject</k>
-<v>48190</v>
+<v>48189</v>
 </e>
 <e>
 <k>@declfunctionobject</k>
@@ -3695,7 +3695,7 @@
 </e>
 <e>
 <k>simple</k>
-<v>170</v>
+<v>169</v>
 </e>
 </columnsizes>
 <dependencies>
@@ -3773,12 +3773,12 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>152</v>
+<v>150</v>
 </b>
 <b>
 <a>2</a>
 <b>3</b>
-<v>16</v>
+<v>17</v>
 </b>
 <b>
 <a>5</a>
@@ -3799,12 +3799,12 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>152</v>
+<v>150</v>
 </b>
 <b>
 <a>2</a>
 <b>3</b>
-<v>16</v>
+<v>17</v>
 </b>
 <b>
 <a>5</a>
@@ -7188,11 +7188,11 @@
 </relation>
 <relation>
 <name>objects</name>
-<cardinality>80104</cardinality>
+<cardinality>80103</cardinality>
 <columnsizes>
 <e>
 <k>id</k>
-<v>80104</v>
+<v>80103</v>
 </e>
 <e>
 <k>kind</k>
@@ -7214,7 +7214,7 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>80104</v>
+<v>80103</v>
 </b>
 </bs>
 </hist>
@@ -7230,7 +7230,7 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>80104</v>
+<v>80103</v>
 </b>
 </bs>
 </hist>
@@ -7284,8 +7284,8 @@
 <v>1</v>
 </b>
 <b>
-<a>48190</a>
-<b>48191</b>
+<a>48189</a>
+<b>48190</b>
 <v>1</v>
 </b>
 </bs>
@@ -7477,11 +7477,11 @@
 </relation>
 <relation>
 <name>objecttypes</name>
-<cardinality>80102</cardinality>
+<cardinality>80101</cardinality>
 <columnsizes>
 <e>
 <k>object</k>
-<v>80102</v>
+<v>80101</v>
 </e>
 <e>
 <k>tp</k>
@@ -7499,7 +7499,7 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>80102</v>
+<v>80101</v>
 </b>
 </bs>
 </hist>
@@ -7598,11 +7598,11 @@
 </relation>
 <relation>
 <name>fieldstructs</name>
-<cardinality>10267</cardinality>
+<cardinality>10266</cardinality>
 <columnsizes>
 <e>
 <k>field</k>
-<v>10267</v>
+<v>10266</v>
 </e>
 <e>
 <k>struct</k>
@@ -7620,7 +7620,7 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>10267</v>
+<v>10266</v>
 </b>
 </bs>
 </hist>
@@ -7661,12 +7661,12 @@
 <b>
 <a>6</a>
 <b>8</b>
-<v>199</v>
+<v>200</v>
 </b>
 <b>
 <a>8</a>
 <b>13</b>
-<v>175</v>
+<v>174</v>
 </b>
 <b>
 <a>13</a>
@@ -7680,6 +7680,89 @@
 </dependencies>
 </relation>
 <relation>
+<name>methodhosts</name>
+<cardinality>8700</cardinality>
+<columnsizes>
+<e>
+<k>method</k>
+<v>8700</v>
+</e>
+<e>
+<k>host</k>
+<v>1765</v>
+</e>
+</columnsizes>
+<dependencies>
+<dep>
+<src>method</src>
+<trg>host</trg>
+<val>
+<hist>
+<budget>12</budget>
+<bs>
+<b>
+<a>1</a>
+<b>2</b>
+<v>8700</v>
+</b>
+</bs>
+</hist>
+</val>
+</dep>
+<dep>
+<src>host</src>
+<trg>method</trg>
+<val>
+<hist>
+<budget>12</budget>
+<bs>
+<b>
+<a>1</a>
+<b>2</b>
+<v>466</v>
+</b>
+<b>
+<a>2</a>
+<b>3</b>
+<v>374</v>
+</b>
+<b>
+<a>3</a>
+<b>4</b>
+<v>308</v>
+</b>
+<b>
+<a>4</a>
+<b>5</b>
+<v>116</v>
+</b>
+<b>
+<a>5</a>
+<b>6</b>
+<v>144</v>
+</b>
+<b>
+<a>6</a>
+<b>9</b>
+<v>146</v>
+</b>
+<b>
+<a>9</a>
+<b>20</b>
+<v>136</v>
+</b>
+<b>
+<a>20</a>
+<b>124</b>
+<v>75</v>
+</b>
+</bs>
+</hist>
+</val>
+</dep>
+</dependencies>
+</relation>
+<relation>
 <name>defs</name>
 <cardinality>38467</cardinality>
 <columnsizes>
@@ -8263,7 +8346,7 @@
 </relation>
 <relation>
 <name>component_types</name>
-<cardinality>34045</cardinality>
+<cardinality>34044</cardinality>
 <columnsizes>
 <e>
 <k>parent</k>
@@ -8516,7 +8599,7 @@
 </b>
 <b>
 <a>215</a>
-<b>755</b>
+<b>756</b>
 <v>6</v>
 </b>
 <b>
@@ -8614,12 +8697,12 @@
 <b>
 <a>3</a>
 <b>5</b>
-<v>397</v>
+<v>398</v>
 </b>
 <b>
 <a>5</a>
 <b>8392</b>
-<v>314</v>
+<v>313</v>
 </b>
 </bs>
 </hist>
@@ -8635,22 +8718,22 @@
 <b>
 <a>1</a>
 <b>2</b>
-<v>4007</v>
+<v>4004</v>
 </b>
 <b>
 <a>2</a>
 <b>3</b>
-<v>675</v>
+<v>678</v>
 </b>
 <b>
 <a>3</a>
 <b>6</b>
-<v>405</v>
+<v>404</v>
 </b>
 <b>
 <a>6</a>
 <b>28</b>
-<v>75</v>
+<v>76</v>
 </b>
 </bs>
 </hist>
@@ -8753,12 +8836,12 @@
 <b>
 <a>4</a>
 <b>5</b>
-<v>331</v>
+<v>332</v>
 </b>
 <b>
 <a>5</a>
 <b>10</b>
-<v>319</v>
+<v>318</v>
 </b>
 <b>
 <a>10</a>
diff --git a/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/go.dbscheme b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/go.dbscheme
new file mode 100644
index 00000000000..391ab3ba573
--- /dev/null
+++ b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/go.dbscheme
@@ -0,0 +1,404 @@
+/** Auto-generated dbscheme; do not edit. */
+
+
+/** Duplicate code **/
+
+duplicateCode(
+  unique int id : @duplication,
+  varchar(900) relativePath : string ref,
+  int equivClass : int ref);
+
+similarCode(
+  unique int id : @similarity,
+  varchar(900) relativePath : string ref,
+  int equivClass : int ref);
+
+@duplication_or_similarity = @duplication | @similarity;
+
+tokens(
+  int id : @duplication_or_similarity ref,
+  int offset : int ref,
+  int beginLine : int ref,
+  int beginColumn : int ref,
+  int endLine : int ref,
+  int endColumn : int ref);
+
+/** External data **/
+
+externalData(
+  int id : @externalDataElement,
+  varchar(900) path : string ref,
+  int column: int ref,
+  varchar(900) value : string ref
+);
+
+snapshotDate(unique date snapshotDate : date ref);
+
+sourceLocationPrefix(varchar(900) prefix : string ref);
+
+locations_default(unique int id: @location_default, int file: @file ref, int beginLine: int ref, int beginColumn: int ref,
+                  int endLine: int ref, int endColumn: int ref);
+
+numlines(int element_id: @sourceline ref, int num_lines: int ref, int num_code: int ref, int num_comment: int ref);
+
+files(unique int id: @file, string name: string ref, string simple: string ref, string ext: string ref, int fromSource: int ref);
+
+folders(unique int id: @folder, string name: string ref, string simple: string ref);
+
+containerparent(int parent: @container ref, unique int child: @container ref);
+
+has_location(unique int locatable: @locatable ref, int location: @location ref);
+
+comment_groups(unique int id: @comment_group);
+
+comments(unique int id: @comment, int kind: int ref, int parent: @comment_group ref, int idx: int ref, string text: string ref);
+
+doc_comments(unique int node: @documentable ref, int comment: @comment_group ref);
+
+#keyset[parent, idx]
+exprs(unique int id: @expr, int kind: int ref, int parent: @exprparent ref, int idx: int ref);
+
+literals(unique int expr: @expr ref, string value: string ref, string raw: string ref);
+
+constvalues(unique int expr: @expr ref, string value: string ref, string exact: string ref);
+
+fields(unique int id: @field, int parent: @fieldparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+stmts(unique int id: @stmt, int kind: int ref, int parent: @stmtparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+decls(unique int id: @decl, int kind: int ref, int parent: @declparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+specs(unique int id: @spec, int kind: int ref, int parent: @gendecl ref, int idx: int ref);
+
+scopes(unique int id: @scope, int kind: int ref);
+
+scopenesting(unique int inner: @scope ref, int outer: @scope ref);
+
+scopenodes(unique int node: @scopenode ref, int scope: @localscope ref);
+
+objects(unique int id: @object, int kind: int ref, string name: string ref);
+
+objectscopes(unique int object: @object ref, int scope: @scope ref);
+
+objecttypes(unique int object: @object ref, int tp: @type ref);
+
+methodreceivers(unique int method: @object ref, int receiver: @object ref);
+
+fieldstructs(unique int field: @object ref, int struct: @structtype ref);
+
+methodhosts(unique int method: @object ref, int host: @namedtype ref);
+
+defs(int ident: @ident ref, int object: @object ref);
+
+uses(int ident: @ident ref, int object: @object ref);
+
+types(unique int id: @type, int kind: int ref);
+
+type_of(unique int expr: @expr ref, int tp: @type ref);
+
+typename(unique int tp: @type ref, string name: string ref);
+
+key_type(unique int map: @maptype ref, int tp: @type ref);
+
+element_type(unique int container: @containertype ref, int tp: @type ref);
+
+base_type(unique int ptr: @pointertype ref, int tp: @type ref);
+
+underlying_type(unique int named: @namedtype ref, int tp: @type ref);
+
+#keyset[parent, index]
+component_types(int parent: @compositetype ref, int index: int ref, string name: string ref, int tp: @type ref);
+
+array_length(unique int tp: @arraytype ref, string len: string ref);
+
+type_objects(unique int tp: @type ref, int object: @object ref);
+
+packages(unique int id: @package, string name: string ref, string path: string ref, int scope: @packagescope ref);
+
+@container = @file | @folder;
+
+@locatable = @node | @localscope;
+
+@node = @documentable | @exprparent | @fieldparent | @stmtparent | @declparent | @scopenode | @comment_group | @comment;
+
+@documentable = @file | @field | @spec | @gendecl | @funcdecl;
+
+@exprparent = @funcdef | @file | @expr | @field | @stmt | @decl | @spec;
+
+@fieldparent = @decl | @structtypeexpr | @functypeexpr | @interfacetypeexpr;
+
+@stmtparent = @funcdef | @stmt | @decl;
+
+@declparent = @file | @declstmt;
+
+@funcdef = @funclit | @funcdecl;
+
+@scopenode = @file | @functypeexpr | @blockstmt | @ifstmt | @caseclause | @switchstmt | @commclause | @loopstmt;
+
+@location = @location_default;
+
+@sourceline = @locatable;
+
+case @comment.kind of
+  0 = @slashslashcomment
+| 1 = @slashstarcomment;
+
+case @expr.kind of
+  0 = @badexpr
+| 1 = @ident
+| 2 = @ellipsis
+| 3 = @intlit
+| 4 = @floatlit
+| 5 = @imaglit
+| 6 = @charlit
+| 7 = @stringlit
+| 8 = @funclit
+| 9 = @compositelit
+| 10 = @parenexpr
+| 11 = @selectorexpr
+| 12 = @indexexpr
+| 13 = @sliceexpr
+| 14 = @typeassertexpr
+| 15 = @callorconversionexpr
+| 16 = @starexpr
+| 17 = @keyvalueexpr
+| 18 = @arraytypeexpr
+| 19 = @structtypeexpr
+| 20 = @functypeexpr
+| 21 = @interfacetypeexpr
+| 22 = @maptypeexpr
+| 23 = @plusexpr
+| 24 = @minusexpr
+| 25 = @notexpr
+| 26 = @complementexpr
+| 27 = @derefexpr
+| 28 = @addressexpr
+| 29 = @arrowexpr
+| 30 = @lorexpr
+| 31 = @landexpr
+| 32 = @eqlexpr
+| 33 = @neqexpr
+| 34 = @lssexpr
+| 35 = @leqexpr
+| 36 = @gtrexpr
+| 37 = @geqexpr
+| 38 = @addexpr
+| 39 = @subexpr
+| 40 = @orexpr
+| 41 = @xorexpr
+| 42 = @mulexpr
+| 43 = @quoexpr
+| 44 = @remexpr
+| 45 = @shlexpr
+| 46 = @shrexpr
+| 47 = @andexpr
+| 48 = @andnotexpr
+| 49 = @sendchantypeexpr
+| 50 = @recvchantypeexpr
+| 51 = @sendrcvchantypeexpr;
+
+@basiclit = @intlit | @floatlit | @imaglit | @charlit | @stringlit;
+
+@operatorexpr = @logicalexpr | @arithmeticexpr | @bitwiseexpr | @unaryexpr | @binaryexpr;
+
+@logicalexpr = @logicalunaryexpr | @logicalbinaryexpr;
+
+@arithmeticexpr = @arithmeticunaryexpr | @arithmeticbinaryexpr;
+
+@bitwiseexpr = @bitwiseunaryexpr | @bitwisebinaryexpr;
+
+@unaryexpr = @logicalunaryexpr | @bitwiseunaryexpr | @arithmeticunaryexpr | @derefexpr | @addressexpr | @arrowexpr;
+
+@logicalunaryexpr = @notexpr;
+
+@bitwiseunaryexpr = @complementexpr;
+
+@arithmeticunaryexpr = @plusexpr | @minusexpr;
+
+@binaryexpr = @logicalbinaryexpr | @bitwisebinaryexpr | @arithmeticbinaryexpr | @comparison;
+
+@logicalbinaryexpr = @lorexpr | @landexpr;
+
+@bitwisebinaryexpr = @shiftexpr | @orexpr | @xorexpr | @andexpr | @andnotexpr;
+
+@arithmeticbinaryexpr = @addexpr | @subexpr | @mulexpr | @quoexpr | @remexpr;
+
+@shiftexpr = @shlexpr | @shrexpr;
+
+@comparison = @equalitytest | @relationalcomparison;
+
+@equalitytest = @eqlexpr | @neqexpr;
+
+@relationalcomparison = @lssexpr | @leqexpr | @gtrexpr | @geqexpr;
+
+@chantypeexpr = @sendchantypeexpr | @recvchantypeexpr | @sendrcvchantypeexpr;
+
+case @stmt.kind of
+  0 = @badstmt
+| 1 = @declstmt
+| 2 = @emptystmt
+| 3 = @labeledstmt
+| 4 = @exprstmt
+| 5 = @sendstmt
+| 6 = @incstmt
+| 7 = @decstmt
+| 8 = @gostmt
+| 9 = @deferstmt
+| 10 = @returnstmt
+| 11 = @breakstmt
+| 12 = @continuestmt
+| 13 = @gotostmt
+| 14 = @fallthroughstmt
+| 15 = @blockstmt
+| 16 = @ifstmt
+| 17 = @caseclause
+| 18 = @exprswitchstmt
+| 19 = @typeswitchstmt
+| 20 = @commclause
+| 21 = @selectstmt
+| 22 = @forstmt
+| 23 = @rangestmt
+| 24 = @assignstmt
+| 25 = @definestmt
+| 26 = @addassignstmt
+| 27 = @subassignstmt
+| 28 = @mulassignstmt
+| 29 = @quoassignstmt
+| 30 = @remassignstmt
+| 31 = @andassignstmt
+| 32 = @orassignstmt
+| 33 = @xorassignstmt
+| 34 = @shlassignstmt
+| 35 = @shrassignstmt
+| 36 = @andnotassignstmt;
+
+@incdecstmt = @incstmt | @decstmt;
+
+@assignment = @simpleassignstmt | @compoundassignstmt;
+
+@simpleassignstmt = @assignstmt | @definestmt;
+
+@compoundassignstmt = @addassignstmt | @subassignstmt | @mulassignstmt | @quoassignstmt | @remassignstmt
+                    | @andassignstmt | @orassignstmt | @xorassignstmt | @shlassignstmt | @shrassignstmt | @andnotassignstmt;
+
+@branchstmt = @breakstmt | @continuestmt | @gotostmt | @fallthroughstmt;
+
+@switchstmt = @exprswitchstmt | @typeswitchstmt;
+
+@loopstmt = @forstmt | @rangestmt;
+
+case @decl.kind of
+  0 = @baddecl
+| 1 = @importdecl
+| 2 = @constdecl
+| 3 = @typedecl
+| 4 = @vardecl
+| 5 = @funcdecl;
+
+@gendecl = @importdecl | @constdecl | @typedecl | @vardecl;
+
+case @spec.kind of
+  0 = @importspec
+| 1 = @valuespec
+| 2 = @typespec;
+
+case @object.kind of
+  0 = @pkgobject
+| 1 = @decltypeobject
+| 2 = @builtintypeobject
+| 3 = @declconstobject
+| 4 = @builtinconstobject
+| 5 = @declvarobject
+| 6 = @declfunctionobject
+| 7 = @builtinfunctionobject
+| 8 = @labelobject;
+
+@declobject = @decltypeobject | @declconstobject | @declvarobject | @declfunctionobject;
+
+@builtinobject = @builtintypeobject | @builtinconstobject | @builtinfunctionobject;
+
+@typeobject = @decltypeobject | @builtintypeobject;
+
+@valueobject = @constobject | @varobject | @functionobject;
+
+@constobject = @declconstobject | @builtinconstobject;
+
+@varobject = @declvarobject;
+
+@functionobject = @declfunctionobject | @builtinfunctionobject;
+
+case @scope.kind of
+  0 = @universescope
+| 1 = @packagescope
+| 2 = @localscope;
+
+case @type.kind of
+  0 = @invalidtype
+| 1 = @boolexprtype
+| 2 = @inttype
+| 3 = @int8type
+| 4 = @int16type
+| 5 = @int32type
+| 6 = @int64type
+| 7 = @uinttype
+| 8 = @uint8type
+| 9 = @uint16type
+| 10 = @uint32type
+| 11 = @uint64type
+| 12 = @uintptrtype
+| 13 = @float32type
+| 14 = @float64type
+| 15 = @complex64type
+| 16 = @complex128type
+| 17 = @stringexprtype
+| 18 = @unsafepointertype
+| 19 = @boolliteraltype
+| 20 = @intliteraltype
+| 21 = @runeliteraltype
+| 22 = @floatliteraltype
+| 23 = @complexliteraltype
+| 24 = @stringliteraltype
+| 25 = @nilliteraltype
+| 26 = @arraytype
+| 27 = @slicetype
+| 28 = @structtype
+| 29 = @pointertype
+| 30 = @interfacetype
+| 31 = @tupletype
+| 32 = @signaturetype
+| 33 = @maptype
+| 34 = @sendchantype
+| 35 = @recvchantype
+| 36 = @sendrcvchantype
+| 37 = @namedtype;
+
+@basictype = @booltype | @numerictype | @stringtype | @literaltype | @invalidtype | @uintptrtype | @unsafepointertype;
+
+@booltype = @boolexprtype | @boolliteraltype;
+
+@numerictype = @integertype | @floattype | @complextype;
+
+@integertype = @signedintegertype | @unsignedintegertype;
+
+@signedintegertype = @inttype | @int8type | @int16type | @int32type | @int64type | @intliteraltype | @runeliteraltype;
+
+@unsignedintegertype = @uinttype | @uint8type | @uint16type | @uint32type | @uint64type;
+
+@floattype = @float32type | @float64type | @floatliteraltype;
+
+@complextype = @complex64type | @complex128type | @complexliteraltype;
+
+@stringtype = @stringexprtype | @stringliteraltype;
+
+@literaltype = @boolliteraltype | @intliteraltype | @runeliteraltype | @floatliteraltype | @complexliteraltype
+             | @stringliteraltype | @nilliteraltype;
+
+@compositetype = @containertype | @structtype | @pointertype | @interfacetype | @tupletype | @signaturetype | @namedtype;
+
+@containertype = @arraytype | @slicetype | @maptype | @chantype;
+
+@chantype = @sendchantype | @recvchantype | @sendrcvchantype;
+
diff --git a/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/old.dbscheme b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/old.dbscheme
new file mode 100644
index 00000000000..ffced433fce
--- /dev/null
+++ b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/old.dbscheme
@@ -0,0 +1,402 @@
+/** Auto-generated dbscheme; do not edit. */
+
+
+/** Duplicate code **/
+
+duplicateCode(
+  unique int id : @duplication,
+  varchar(900) relativePath : string ref,
+  int equivClass : int ref);
+
+similarCode(
+  unique int id : @similarity,
+  varchar(900) relativePath : string ref,
+  int equivClass : int ref);
+
+@duplication_or_similarity = @duplication | @similarity;
+
+tokens(
+  int id : @duplication_or_similarity ref,
+  int offset : int ref,
+  int beginLine : int ref,
+  int beginColumn : int ref,
+  int endLine : int ref,
+  int endColumn : int ref);
+
+/** External data **/
+
+externalData(
+  int id : @externalDataElement,
+  varchar(900) path : string ref,
+  int column: int ref,
+  varchar(900) value : string ref
+);
+
+snapshotDate(unique date snapshotDate : date ref);
+
+sourceLocationPrefix(varchar(900) prefix : string ref);
+
+locations_default(unique int id: @location_default, int file: @file ref, int beginLine: int ref, int beginColumn: int ref,
+                  int endLine: int ref, int endColumn: int ref);
+
+numlines(int element_id: @sourceline ref, int num_lines: int ref, int num_code: int ref, int num_comment: int ref);
+
+files(unique int id: @file, string name: string ref, string simple: string ref, string ext: string ref, int fromSource: int ref);
+
+folders(unique int id: @folder, string name: string ref, string simple: string ref);
+
+containerparent(int parent: @container ref, unique int child: @container ref);
+
+has_location(unique int locatable: @locatable ref, int location: @location ref);
+
+comment_groups(unique int id: @comment_group);
+
+comments(unique int id: @comment, int kind: int ref, int parent: @comment_group ref, int idx: int ref, string text: string ref);
+
+doc_comments(unique int node: @documentable ref, int comment: @comment_group ref);
+
+#keyset[parent, idx]
+exprs(unique int id: @expr, int kind: int ref, int parent: @exprparent ref, int idx: int ref);
+
+literals(unique int expr: @expr ref, string value: string ref, string raw: string ref);
+
+constvalues(unique int expr: @expr ref, string value: string ref, string exact: string ref);
+
+fields(unique int id: @field, int parent: @fieldparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+stmts(unique int id: @stmt, int kind: int ref, int parent: @stmtparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+decls(unique int id: @decl, int kind: int ref, int parent: @declparent ref, int idx: int ref);
+
+#keyset[parent, idx]
+specs(unique int id: @spec, int kind: int ref, int parent: @gendecl ref, int idx: int ref);
+
+scopes(unique int id: @scope, int kind: int ref);
+
+scopenesting(unique int inner: @scope ref, int outer: @scope ref);
+
+scopenodes(unique int node: @scopenode ref, int scope: @localscope ref);
+
+objects(unique int id: @object, int kind: int ref, string name: string ref);
+
+objectscopes(unique int object: @object ref, int scope: @scope ref);
+
+objecttypes(unique int object: @object ref, int tp: @type ref);
+
+methodreceivers(unique int method: @object ref, int receiver: @object ref);
+
+fieldstructs(unique int field: @object ref, int struct: @structtype ref);
+
+defs(int ident: @ident ref, int object: @object ref);
+
+uses(int ident: @ident ref, int object: @object ref);
+
+types(unique int id: @type, int kind: int ref);
+
+type_of(unique int expr: @expr ref, int tp: @type ref);
+
+typename(unique int tp: @type ref, string name: string ref);
+
+key_type(unique int map: @maptype ref, int tp: @type ref);
+
+element_type(unique int container: @containertype ref, int tp: @type ref);
+
+base_type(unique int ptr: @pointertype ref, int tp: @type ref);
+
+underlying_type(unique int named: @namedtype ref, int tp: @type ref);
+
+#keyset[parent, index]
+component_types(int parent: @compositetype ref, int index: int ref, string name: string ref, int tp: @type ref);
+
+array_length(unique int tp: @arraytype ref, string len: string ref);
+
+type_objects(unique int tp: @type ref, int object: @object ref);
+
+packages(unique int id: @package, string name: string ref, string path: string ref, int scope: @packagescope ref);
+
+@container = @file | @folder;
+
+@locatable = @node | @localscope;
+
+@node = @documentable | @exprparent | @fieldparent | @stmtparent | @declparent | @scopenode | @comment_group | @comment;
+
+@documentable = @file | @field | @spec | @gendecl | @funcdecl;
+
+@exprparent = @funcdef | @file | @expr | @field | @stmt | @decl | @spec;
+
+@fieldparent = @decl | @structtypeexpr | @functypeexpr | @interfacetypeexpr;
+
+@stmtparent = @funcdef | @stmt | @decl;
+
+@declparent = @file | @declstmt;
+
+@funcdef = @funclit | @funcdecl;
+
+@scopenode = @file | @functypeexpr | @blockstmt | @ifstmt | @caseclause | @switchstmt | @commclause | @loopstmt;
+
+@location = @location_default;
+
+@sourceline = @locatable;
+
+case @comment.kind of
+  0 = @slashslashcomment
+| 1 = @slashstarcomment;
+
+case @expr.kind of
+  0 = @badexpr
+| 1 = @ident
+| 2 = @ellipsis
+| 3 = @intlit
+| 4 = @floatlit
+| 5 = @imaglit
+| 6 = @charlit
+| 7 = @stringlit
+| 8 = @funclit
+| 9 = @compositelit
+| 10 = @parenexpr
+| 11 = @selectorexpr
+| 12 = @indexexpr
+| 13 = @sliceexpr
+| 14 = @typeassertexpr
+| 15 = @callorconversionexpr
+| 16 = @starexpr
+| 17 = @keyvalueexpr
+| 18 = @arraytypeexpr
+| 19 = @structtypeexpr
+| 20 = @functypeexpr
+| 21 = @interfacetypeexpr
+| 22 = @maptypeexpr
+| 23 = @plusexpr
+| 24 = @minusexpr
+| 25 = @notexpr
+| 26 = @complementexpr
+| 27 = @derefexpr
+| 28 = @addressexpr
+| 29 = @arrowexpr
+| 30 = @lorexpr
+| 31 = @landexpr
+| 32 = @eqlexpr
+| 33 = @neqexpr
+| 34 = @lssexpr
+| 35 = @leqexpr
+| 36 = @gtrexpr
+| 37 = @geqexpr
+| 38 = @addexpr
+| 39 = @subexpr
+| 40 = @orexpr
+| 41 = @xorexpr
+| 42 = @mulexpr
+| 43 = @quoexpr
+| 44 = @remexpr
+| 45 = @shlexpr
+| 46 = @shrexpr
+| 47 = @andexpr
+| 48 = @andnotexpr
+| 49 = @sendchantypeexpr
+| 50 = @recvchantypeexpr
+| 51 = @sendrcvchantypeexpr;
+
+@basiclit = @intlit | @floatlit | @imaglit | @charlit | @stringlit;
+
+@operatorexpr = @logicalexpr | @arithmeticexpr | @bitwiseexpr | @unaryexpr | @binaryexpr;
+
+@logicalexpr = @logicalunaryexpr | @logicalbinaryexpr;
+
+@arithmeticexpr = @arithmeticunaryexpr | @arithmeticbinaryexpr;
+
+@bitwiseexpr = @bitwiseunaryexpr | @bitwisebinaryexpr;
+
+@unaryexpr = @logicalunaryexpr | @bitwiseunaryexpr | @arithmeticunaryexpr | @derefexpr | @addressexpr | @arrowexpr;
+
+@logicalunaryexpr = @notexpr;
+
+@bitwiseunaryexpr = @complementexpr;
+
+@arithmeticunaryexpr = @plusexpr | @minusexpr;
+
+@binaryexpr = @logicalbinaryexpr | @bitwisebinaryexpr | @arithmeticbinaryexpr | @comparison;
+
+@logicalbinaryexpr = @lorexpr | @landexpr;
+
+@bitwisebinaryexpr = @shiftexpr | @orexpr | @xorexpr | @andexpr | @andnotexpr;
+
+@arithmeticbinaryexpr = @addexpr | @subexpr | @mulexpr | @quoexpr | @remexpr;
+
+@shiftexpr = @shlexpr | @shrexpr;
+
+@comparison = @equalitytest | @relationalcomparison;
+
+@equalitytest = @eqlexpr | @neqexpr;
+
+@relationalcomparison = @lssexpr | @leqexpr | @gtrexpr | @geqexpr;
+
+@chantypeexpr = @sendchantypeexpr | @recvchantypeexpr | @sendrcvchantypeexpr;
+
+case @stmt.kind of
+  0 = @badstmt
+| 1 = @declstmt
+| 2 = @emptystmt
+| 3 = @labeledstmt
+| 4 = @exprstmt
+| 5 = @sendstmt
+| 6 = @incstmt
+| 7 = @decstmt
+| 8 = @gostmt
+| 9 = @deferstmt
+| 10 = @returnstmt
+| 11 = @breakstmt
+| 12 = @continuestmt
+| 13 = @gotostmt
+| 14 = @fallthroughstmt
+| 15 = @blockstmt
+| 16 = @ifstmt
+| 17 = @caseclause
+| 18 = @exprswitchstmt
+| 19 = @typeswitchstmt
+| 20 = @commclause
+| 21 = @selectstmt
+| 22 = @forstmt
+| 23 = @rangestmt
+| 24 = @assignstmt
+| 25 = @definestmt
+| 26 = @addassignstmt
+| 27 = @subassignstmt
+| 28 = @mulassignstmt
+| 29 = @quoassignstmt
+| 30 = @remassignstmt
+| 31 = @andassignstmt
+| 32 = @orassignstmt
+| 33 = @xorassignstmt
+| 34 = @shlassignstmt
+| 35 = @shrassignstmt
+| 36 = @andnotassignstmt;
+
+@incdecstmt = @incstmt | @decstmt;
+
+@assignment = @simpleassignstmt | @compoundassignstmt;
+
+@simpleassignstmt = @assignstmt | @definestmt;
+
+@compoundassignstmt = @addassignstmt | @subassignstmt | @mulassignstmt | @quoassignstmt | @remassignstmt
+                    | @andassignstmt | @orassignstmt | @xorassignstmt | @shlassignstmt | @shrassignstmt | @andnotassignstmt;
+
+@branchstmt = @breakstmt | @continuestmt | @gotostmt | @fallthroughstmt;
+
+@switchstmt = @exprswitchstmt | @typeswitchstmt;
+
+@loopstmt = @forstmt | @rangestmt;
+
+case @decl.kind of
+  0 = @baddecl
+| 1 = @importdecl
+| 2 = @constdecl
+| 3 = @typedecl
+| 4 = @vardecl
+| 5 = @funcdecl;
+
+@gendecl = @importdecl | @constdecl | @typedecl | @vardecl;
+
+case @spec.kind of
+  0 = @importspec
+| 1 = @valuespec
+| 2 = @typespec;
+
+case @object.kind of
+  0 = @pkgobject
+| 1 = @decltypeobject
+| 2 = @builtintypeobject
+| 3 = @declconstobject
+| 4 = @builtinconstobject
+| 5 = @declvarobject
+| 6 = @declfunctionobject
+| 7 = @builtinfunctionobject
+| 8 = @labelobject;
+
+@declobject = @decltypeobject | @declconstobject | @declvarobject | @declfunctionobject;
+
+@builtinobject = @builtintypeobject | @builtinconstobject | @builtinfunctionobject;
+
+@typeobject = @decltypeobject | @builtintypeobject;
+
+@valueobject = @constobject | @varobject | @functionobject;
+
+@constobject = @declconstobject | @builtinconstobject;
+
+@varobject = @declvarobject;
+
+@functionobject = @declfunctionobject | @builtinfunctionobject;
+
+case @scope.kind of
+  0 = @universescope
+| 1 = @packagescope
+| 2 = @localscope;
+
+case @type.kind of
+  0 = @invalidtype
+| 1 = @boolexprtype
+| 2 = @inttype
+| 3 = @int8type
+| 4 = @int16type
+| 5 = @int32type
+| 6 = @int64type
+| 7 = @uinttype
+| 8 = @uint8type
+| 9 = @uint16type
+| 10 = @uint32type
+| 11 = @uint64type
+| 12 = @uintptrtype
+| 13 = @float32type
+| 14 = @float64type
+| 15 = @complex64type
+| 16 = @complex128type
+| 17 = @stringexprtype
+| 18 = @unsafepointertype
+| 19 = @boolliteraltype
+| 20 = @intliteraltype
+| 21 = @runeliteraltype
+| 22 = @floatliteraltype
+| 23 = @complexliteraltype
+| 24 = @stringliteraltype
+| 25 = @nilliteraltype
+| 26 = @arraytype
+| 27 = @slicetype
+| 28 = @structtype
+| 29 = @pointertype
+| 30 = @interfacetype
+| 31 = @tupletype
+| 32 = @signaturetype
+| 33 = @maptype
+| 34 = @sendchantype
+| 35 = @recvchantype
+| 36 = @sendrcvchantype
+| 37 = @namedtype;
+
+@basictype = @booltype | @numerictype | @stringtype | @literaltype | @invalidtype | @uintptrtype | @unsafepointertype;
+
+@booltype = @boolexprtype | @boolliteraltype;
+
+@numerictype = @integertype | @floattype | @complextype;
+
+@integertype = @signedintegertype | @unsignedintegertype;
+
+@signedintegertype = @inttype | @int8type | @int16type | @int32type | @int64type | @intliteraltype | @runeliteraltype;
+
+@unsignedintegertype = @uinttype | @uint8type | @uint16type | @uint32type | @uint64type;
+
+@floattype = @float32type | @float64type | @floatliteraltype;
+
+@complextype = @complex64type | @complex128type | @complexliteraltype;
+
+@stringtype = @stringexprtype | @stringliteraltype;
+
+@literaltype = @boolliteraltype | @intliteraltype | @runeliteraltype | @floatliteraltype | @complexliteraltype
+             | @stringliteraltype | @nilliteraltype;
+
+@compositetype = @containertype | @structtype | @pointertype | @interfacetype | @tupletype | @signaturetype | @namedtype;
+
+@containertype = @arraytype | @slicetype | @maptype | @chantype;
+
+@chantype = @sendchantype | @recvchantype | @sendrcvchantype;
+
diff --git a/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/upgrade.properties b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/upgrade.properties
new file mode 100644
index 00000000000..3991a8ad4ed
--- /dev/null
+++ b/upgrades/ffced433fce33521f90c1b6c66b611902cdceac2/upgrade.properties
@@ -0,0 +1,2 @@
+description: Add table associating methods with interfaces
+compatibility: backwards