cmd/go: populate module info even if an error occurs in loading package

The existing implementation ignores module info if there is any error loading the package.

Fixes golang#44287

Author: unbyte

src/cmd/go/internal/load/pkg.go

@@ -1846,6 +1846,14 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 	stk.Push(path)
 	defer stk.Pop()
 
+	mainPath := p.ImportPath
+	if p.Internal.CmdlineFiles {
+		mainPath = "command-line-arguments"
+	}
+	if cfg.ModulesEnabled {
+		p.Module = modload.PackageModuleInfo(ctx, mainPath)
+	}
+
 	p.EmbedFiles, p.Internal.Embed, err = resolveEmbed(p.Dir, p.EmbedPatterns)
 	if err != nil {
 		p.Incomplete = true
@@ -1905,6 +1913,10 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 	p.Internal.Imports = imports
 	p.collectDeps()
 
+	if cfg.ModulesEnabled && p.Error == nil && p.Name == "main" && len(p.DepsErrors) == 0 {
+		p.Internal.BuildInfo = modload.PackageBuildInfo(mainPath, p.Deps)
+	}
+
 	// unsafe is a fake package.
 	if p.Standard && (p.ImportPath == "unsafe" || cfg.BuildContext.Compiler == "gccgo") {
 		p.Target = ""
@@ -1944,17 +1956,6 @@ func (p *Package) load(ctx context.Context, opts PackageOpts, path string, stk *
 		setError(fmt.Errorf("Fortran source files not allowed when not using cgo or SWIG: %s", strings.Join(p.FFiles, " ")))
 		return
 	}
-
-	if cfg.ModulesEnabled && p.Error == nil {
-		mainPath := p.ImportPath
-		if p.Internal.CmdlineFiles {
-			mainPath = "command-line-arguments"
-		}
-		p.Module = modload.PackageModuleInfo(ctx, mainPath)
-		if p.Name == "main" && len(p.DepsErrors) == 0 {
-			p.Internal.BuildInfo = modload.PackageBuildInfo(mainPath, p.Deps)
-		}
-	}
 }
 
 // An EmbedError indicates a problem with a go:embed directive.

src/cmd/go/testdata/script/list_module_when_error.txt

@@ -0,0 +1,19 @@
+# The Module field should be populated even if there is an error loading the package.
+
+env GO111MODULE=on
+
+go list -e -f {{.Module}}
+stdout '^mod.com$'
+
+-- go.mod --
+module mod.com
+
+go 1.16
+
+-- blah.go --
+package blah
+
+import _ "embed"
+
+//go:embed README.md
+var readme string