gopls/internal/golang/completion: report types in unimported completion

pkgIDmatches handled only the Function, Variable, Struct and Constant symbol
kinds, so an interface or a named non-struct type from a workspace package was
dropped, and a struct type was reported as "var". Report every type as
"type (from ...)", as the other two search paths already do.

All three paths gave a type VariableCompletion, so editors drew a variable icon
beside an item whose detail read "type". Use InterfaceCompletion for an
interface and ClassCompletion otherwise. The standard library and module cache
indexes do not record whether a type is an interface, so those two paths always
use ClassCompletion.

Fixes golang/go#81369

Author: efrem0ff

gopls/internal/golang/completion/unimported.go

@@ -233,9 +233,15 @@ func (c *completer) pkgIDmatches(ctx context.Context, ids []metadata.PackageID,
 					}
 					kind = protocol.FunctionCompletion
 					detail = fmt.Sprintf("func (from %q)", pkg.PkgPath)
-				case protocol.Variable, protocol.Struct:
+				case protocol.Variable:
 					kind = protocol.VariableCompletion
 					detail = fmt.Sprintf("var (from %q)", pkg.PkgPath)
+				case protocol.Interface:
+					kind = protocol.InterfaceCompletion
+					detail = fmt.Sprintf("type (from %q)", pkg.PkgPath)
+				case protocol.Struct, protocol.Class:
+					kind = protocol.ClassCompletion
+					detail = fmt.Sprintf("type (from %q)", pkg.PkgPath)
 				case protocol.Constant:
 					kind = protocol.ConstantCompletion
 					detail = fmt.Sprintf("const (from %q)", pkg.PkgPath)
@@ -284,7 +290,7 @@ func (c *completer) stdlibMatches(pkgs []metadata.PackagePath, pkg metadata.Pack
 					kind = protocol.VariableCompletion
 					detail = fmt.Sprintf("var (from %q)", candpkg)
 				case stdlib.Type:
-					kind = protocol.VariableCompletion
+					kind = protocol.ClassCompletion
 					detail = fmt.Sprintf("type (from %q)", candpkg)
 				default:
 					continue
@@ -331,7 +337,7 @@ func (c *completer) modcacheMatches(pkg metadata.PackageName, prefix string) ([]
 			kind = protocol.ConstantCompletion
 			detail = fmt.Sprintf("const (from %s)", cand.ImportPath)
 		case modindex.Type: // might be a type alias
-			kind = protocol.VariableCompletion
+			kind = protocol.ClassCompletion
 			detail = fmt.Sprintf("type (from %s)", cand.ImportPath)
 		default:
 			continue

gopls/internal/test/marker/testdata/completion/unimported.txt

@@ -21,6 +21,13 @@ func Foo() {}
 package foo
 
 type StructFoo struct{ F int }
+type ArrayFoo [16]byte
+type InterfaceFoo interface{}
+type FuncFoo func(int)
+
+const ConstFoo = 1
+
+var VarFoo = 2
 
 -- baz/baz.go --
 package baz
@@ -41,6 +48,10 @@ func _() {
 	signature.Foo //@complete(re"()Foo", signaturefoo)
 
 	context.Bac //@complete(re"() \\/\\/", contextBackground)
+
+	// Every kind of exported declaration of a workspace package that is not
+	// imported yet.
+	foo. //@complete(re"foo.() \\/\\/", fooArray, fooConst, fooFunc, fooInterface, fooStruct, fooVar)
 }
 
 // Create markers for unimported std lib packages. Only for use by this test.
@@ -49,7 +60,14 @@ func _() {
 /* httptrace */ //@item(httptrace, "httptrace", "\"net/http/httptrace\"", "package")
 /* httputil */ //@item(httputil, "httputil", "\"net/http/httputil\"", "package")
 
-/* ring.Ring */ //@item(ringring, "Ring", "type (from \"container/ring\")", "var")
+/* ring.Ring */ //@item(ringring, "Ring", "type (from \"container/ring\")", "type")
+
+/* foo.ArrayFoo */ //@item(fooArray, "ArrayFoo", "type (from \"unimported.test/foo\")", "type")
+/* foo.ConstFoo */ //@item(fooConst, "ConstFoo", "const (from \"unimported.test/foo\")", "const")
+/* foo.FuncFoo */ //@item(fooFunc, "FuncFoo", "func (from \"unimported.test/foo\")", "func")
+/* foo.InterfaceFoo */ //@item(fooInterface, "InterfaceFoo", "type (from \"unimported.test/foo\")", "interface")
+/* foo.StructFoo */ //@item(fooStruct, "StructFoo", "type (from \"unimported.test/foo\")", "type")
+/* foo.VarFoo */ //@item(fooVar, "VarFoo", "var (from \"unimported.test/foo\")", "var")
 
 /* signature.Foo */ //@item(signaturefoo, "Foo", "func (from \"unimported.test/signature\")", "func")