go/analysis/passes/testinggoroutine: update for generics

Update the testinggoroutine analyzer to find bad calls via instantiated
function calls.

For golang/go#48704

Change-Id: I39ef43090a0e5dd04dfe094376517ac25441ad27
Reviewed-on: https://go-review.googlesource.com/c/tools/+/359401
Trust: Robert Findley <rfindley@google.com>
Trust: Zvonimir Pavlinovic <zpavlinovic@google.com>
Run-TryBot: Robert Findley <rfindley@google.com>
Run-TryBot: Zvonimir Pavlinovic <zpavlinovic@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Zvonimir Pavlinovic <zpavlinovic@google.com>

go/analysis/passes/testinggoroutine/testdata/src/typeparams/typeparams.go

@@ -0,0 +1,17 @@
+// Copyright 2021 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.
+
+package typeparams
+
+import (
+	"testing"
+)
+
+func f[P any](t *testing.T) {
+	t.Fatal("failed")
+}
+
+func TestBadFatalf[P any](t *testing.T) {
+	go f[int](t) // want "call to .+T.+Fatal from a non-test goroutine"
+}

go/analysis/passes/testinggoroutine/testinggoroutine.go

@@ -11,6 +11,7 @@ import (
 	"golang.org/x/tools/go/analysis/passes/inspect"
 	"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
 	"golang.org/x/tools/go/ast/inspector"
+	"golang.org/x/tools/internal/typeparams"
 )
 
 const Doc = `report calls to (*testing.T).Fatal from goroutines started by a test.
@@ -124,16 +125,30 @@ func typeIsTestingDotTOrB(expr ast.Expr) (string, bool) {
 // function literals declared in the same function, and
 // static calls within the same package are supported.
 func goStmtFun(goStmt *ast.GoStmt) ast.Node {
-	switch goStmt.Call.Fun.(type) {
-	case *ast.Ident:
-		id := goStmt.Call.Fun.(*ast.Ident)
-		// TODO(cuonglm): improve this once golang/go#48141 resolved.
+	switch fun := goStmt.Call.Fun.(type) {
+	case *ast.IndexExpr, *typeparams.IndexListExpr:
+		ix := typeparams.GetIndexExprData(fun)
+		if ix == nil {
+			break
+		}
+		id, _ := ix.X.(*ast.Ident)
+		if id == nil {
+			break
+		}
 		if id.Obj == nil {
 			break
 		}
 		if funDecl, ok := id.Obj.Decl.(ast.Node); ok {
 			return funDecl
 		}
+	case *ast.Ident:
+		// TODO(cuonglm): improve this once golang/go#48141 resolved.
+		if fun.Obj == nil {
+			break
+		}
+		if funDecl, ok := fun.Obj.Decl.(ast.Node); ok {
+			return funDecl
+		}
 	case *ast.FuncLit:
 		return goStmt.Call.Fun
 	}

go/analysis/passes/testinggoroutine/testinggoroutine_test.go

@@ -9,9 +9,14 @@ import (
 
 	"golang.org/x/tools/go/analysis/analysistest"
 	"golang.org/x/tools/go/analysis/passes/testinggoroutine"
+	"golang.org/x/tools/internal/typeparams"
 )
 
 func Test(t *testing.T) {
 	testdata := analysistest.TestData()
-	analysistest.Run(t, testdata, testinggoroutine.Analyzer, "a")
+	pkgs := []string{"a"}
+	if typeparams.Enabled {
+		pkgs = append(pkgs, "typeparams")
+	}
+	analysistest.Run(t, testdata, testinggoroutine.Analyzer, pkgs...)
 }