go/ssa: remove outdated doc in CreatePackage and add respective test cases

It also removes the deprecated loader package and uses packages and
txtar to load the package for testing. Now all packages are created
under a go module.

Author: xieyuschen

go/ssa/builder_generic_test.go

@@ -14,7 +14,6 @@ import (
 	"testing"
 
 	"golang.org/x/tools/go/expect"
-	"golang.org/x/tools/go/loader"
 	"golang.org/x/tools/go/ssa"
 )
 
@@ -93,22 +92,22 @@ func TestGenericBodies(t *testing.T) {
 
 		func From() {
 			type A [4]byte
-			print(a[A]) //@ types("func(x p03.A)")
+			print(a[A]) //@ types("func(x example.com.A)")
 
 			type B *[4]byte
-			print(b[B]) //@ types("func(x p03.B)")
+			print(b[B]) //@ types("func(x example.com.B)")
 
 			type C []byte
-			print(c[C]) //@ types("func(x p03.C)")
+			print(c[C]) //@ types("func(x example.com.C)")
 
 			type D string
-			print(d[D]) //@ types("func(x p03.D)")
+			print(d[D]) //@ types("func(x example.com.D)")
 
 			type E map[int]string
-			print(e[E]) //@ types("func(x p03.E)")
+			print(e[E]) //@ types("func(x example.com.E)")
 
 			type F chan string
-			print(f[F]) //@ types("func(x p03.F)")
+			print(f[F]) //@ types("func(x example.com.F)")
 		}
 		`,
 		`
@@ -122,7 +121,7 @@ func TestGenericBodies(t *testing.T) {
 
 		func From() {
 			type F chan string
-			print(f[string, F]) //@ types("func(x p05.F)")
+			print(f[string, F]) //@ types("func(x example.com.F)")
 		}
 		`,
 		`
@@ -152,8 +151,8 @@ func TestGenericBodies(t *testing.T) {
 			type F chan int
 			c := make(F)
 			quit := make(F)
-			print(start[F], c, quit)     //@ types("func(c p06.F, quit p06.F)", "p06.F", "p06.F")
-			print(fibonacci[F], c, quit) //@ types("func(c p06.F, quit p06.F)", "p06.F", "p06.F")
+			print(start[F], c, quit)     //@ types("func(c example.com.F, quit example.com.F)", "example.com.F", "example.com.F")
+			print(fibonacci[F], c, quit) //@ types("func(c example.com.F, quit example.com.F)", "example.com.F", "example.com.F")
 		}
 		`,
 		`
@@ -165,7 +164,7 @@ func TestGenericBodies(t *testing.T) {
 		}
 		func From() {
 			type S struct{ x int; y string }
-			print(f[S])     //@ types("func(i int) p07.S")
+			print(f[S])     //@ types("func(i int) example.com.S")
 		}
 		`,
 		`
@@ -186,7 +185,7 @@ func TestGenericBodies(t *testing.T) {
 			type H []int32
 			print(f[F](F{}, 0, 0))  //@ types("[]int8")
 			print(g[G](nil, 0, 0)) //@ types("[]int16")
-			print(h[H](nil, 0, 0)) //@ types("p08.H")
+			print(h[H](nil, 0, 0)) //@ types("example.com.H")
 		}
 		`,
 		`
@@ -322,18 +321,18 @@ func TestGenericBodies(t *testing.T) {
 		type MyInterface interface{ foo() }
 
 		// ChangeType tests
-		func ct0(x int) { v := MyInt(x);  print(x, v) /*@ types(int, "p15.MyInt")*/ }
+		func ct0(x int) { v := MyInt(x);  print(x, v) /*@ types(int, "example.com.MyInt")*/ }
 		func ct1[T MyInt | Other, S int ](x S) { v := T(x);  print(x, v) /*@ types(S, T)*/ }
 		func ct2[T int, S MyInt | int ](x S) { v := T(x); print(x, v) /*@ types(S, T)*/ }
 		func ct3[T MyInt | Other, S MyInt | int ](x S) { v := T(x) ; print(x, v) /*@ types(S, T)*/ }
 
 		// Convert tests
-		func co0[T int | int8](x MyInt) { v := T(x); print(x, v) /*@ types("p15.MyInt", T)*/}
-		func co1[T int | int8](x T) { v := MyInt(x); print(x, v) /*@ types(T, "p15.MyInt")*/ }
+		func co0[T int | int8](x MyInt) { v := T(x); print(x, v) /*@ types("example.com.MyInt", T)*/}
+		func co1[T int | int8](x T) { v := MyInt(x); print(x, v) /*@ types(T, "example.com.MyInt")*/ }
 		func co2[S, T int | int8](x T) { v := S(x); print(x, v) /*@ types(T, S)*/ }
 
 		// MakeInterface tests
-		func mi0[T MyInterface](x T) { v := MyInterface(x); print(x, v) /*@ types(T, "p15.MyInterface")*/ }
+		func mi0[T MyInterface](x T) { v := MyInterface(x); print(x, v) /*@ types(T, "example.com.MyInterface")*/ }
 
 		// NewConst tests
 		func nc0[T any]() { v := (*T)(nil); print(v) /*@ types("*T")*/}
@@ -427,9 +426,9 @@ func TestGenericBodies(t *testing.T) {
 			Marker()
 		}](v T) {
 			v.Marker()
-			a := *(any(v).(*A)); print(a)  /*@ types("p23.A")*/
-			b := *(any(v).(*B)); print(b)  /*@ types("p23.B")*/
-			c := *(any(v).(*C)); print(c)  /*@ types("p23.C")*/
+			a := *(any(v).(*A)); print(a)  /*@ types("example.com.A")*/
+			b := *(any(v).(*B)); print(b)  /*@ types("example.com.B")*/
+			c := *(any(v).(*C)); print(c)  /*@ types("example.com.C")*/
 		}
 		`,
 		`
@@ -519,32 +518,14 @@ func TestGenericBodies(t *testing.T) {
 		contents := contents
 		pkgname := packageName(t, contents)
 		t.Run(pkgname, func(t *testing.T) {
-			// Parse
-			conf := loader.Config{ParserMode: parser.ParseComments}
-			f, err := conf.ParseFile("file.go", contents)
-			if err != nil {
-				t.Fatalf("parse: %v", err)
-			}
-			conf.CreateFromFiles(pkgname, f)
-
-			// Load
-			lprog, err := conf.Load()
-			if err != nil {
-				t.Fatalf("Load: %v", err)
-			}
+			info := ssa.LoadPackageFromSingleFile(t, contents, ssa.SanityCheckFunctions)
+			p := info.SPkg
+			prog := p.Prog
 
-			// Create and build SSA
-			prog := ssa.NewProgram(lprog.Fset, ssa.SanityCheckFunctions)
-			for _, info := range lprog.AllPackages {
-				if info.TransitivelyErrorFree {
-					prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
-				}
-			}
-			p := prog.Package(lprog.Package(pkgname).Pkg)
 			p.Build()
 
 			// Collect all notes in f, i.e. comments starting with "//@ types".
-			notes, err := expect.ExtractGo(prog.Fset, f)
+			notes, err := expect.ExtractGo(prog.Fset, info.File)
 			if err != nil {
 				t.Errorf("expect.ExtractGo: %v", err)
 			}
@@ -754,33 +735,13 @@ func TestInstructionString(t *testing.T) {
 	}
 	`
 
-	// Parse
-	conf := loader.Config{ParserMode: parser.ParseComments}
-	const fname = "p.go"
-	f, err := conf.ParseFile(fname, contents)
-	if err != nil {
-		t.Fatalf("parse: %v", err)
-	}
-	conf.CreateFromFiles("p", f)
-
-	// Load
-	lprog, err := conf.Load()
-	if err != nil {
-		t.Fatalf("Load: %v", err)
-	}
-
-	// Create and build SSA
-	prog := ssa.NewProgram(lprog.Fset, ssa.SanityCheckFunctions)
-	for _, info := range lprog.AllPackages {
-		if info.TransitivelyErrorFree {
-			prog.CreatePackage(info.Pkg, info.Files, &info.Info, info.Importable)
-		}
-	}
-	p := prog.Package(lprog.Package("p").Pkg)
+	info := ssa.LoadPackageFromSingleFile(t, contents, ssa.SanityCheckFunctions)
+	p := info.SPkg
+	prog := p.Prog
 	p.Build()
 
 	// Collect all notes in f, i.e. comments starting with "//@ instr".
-	notes, err := expect.ExtractGo(prog.Fset, f)
+	notes, err := expect.ExtractGo(prog.Fset, info.File)
 	if err != nil {
 		t.Errorf("expect.ExtractGo: %v", err)
 	}