skip analysis when seeing generics

The analyzers (or helpers that the analyzers use) currently do not
support generics. Use the `usesgenerics` analyzer from the x/tools
repository to detect usage of generics and return a synthesized empty
result in that case.

Updates google/issues/323

Author: chressie

internal/pkg/earpointer/analysis.go

@@ -26,6 +26,7 @@ import (
 
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/buildssa"
+	"golang.org/x/tools/go/analysis/passes/usesgenerics"
 	"golang.org/x/tools/go/callgraph"
 	"golang.org/x/tools/go/callgraph/static"
 	"golang.org/x/tools/go/ssa"
@@ -49,7 +50,7 @@ var Analyzer = &analysis.Analyzer{
 	Flags:      config.FlagSet,
 	Run:        run,
 	ResultType: reflect.TypeOf(new(Partitions)),
-	Requires:   []*analysis.Analyzer{buildssa.Analyzer},
+	Requires:   []*analysis.Analyzer{buildssa.Analyzer, usesgenerics.Analyzer},
 }
 
 // visitor traverse the instructions in a function and perform unifications
@@ -63,6 +64,11 @@ type visitor struct {
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
+	if r, ok := pass.ResultOf[usesgenerics.Analyzer].(*usesgenerics.Result); ok && r.Transitive != 0 {
+		// Generics are not supported yet (https://github.com/google/go-flow-levee/issues/323).
+		// TODO: Remove this check once the analyzers support generics.
+		return &Partitions{}, nil
+	}
 	conf, err := config.ReadConfig()
 	if err != nil {
 		return nil, err

internal/pkg/fieldpropagator/analyzer.go

@@ -26,6 +26,7 @@ import (
 	"github.com/google/go-flow-levee/internal/pkg/utils"
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/buildssa"
+	"golang.org/x/tools/go/analysis/passes/usesgenerics"
 	"golang.org/x/tools/go/ssa"
 )
 
@@ -53,12 +54,17 @@ var Analyzer = &analysis.Analyzer{
 A field propagator is a function that returns a value that is tainted by a source field.`,
 	Flags:      config.FlagSet,
 	Run:        run,
-	Requires:   []*analysis.Analyzer{buildssa.Analyzer, fieldtags.Analyzer},
+	Requires:   []*analysis.Analyzer{buildssa.Analyzer, fieldtags.Analyzer, usesgenerics.Analyzer},
 	ResultType: reflect.TypeOf(new(ResultType)).Elem(),
 	FactTypes:  []analysis.Fact{new(isFieldPropagator)},
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
+	if r := pass.ResultOf[usesgenerics.Analyzer].(*usesgenerics.Result); r.Transitive != 0 {
+		// Generics are not supported yet (https://github.com/google/go-flow-levee/issues/323).
+		// TODO: Remove this check once the analyzers support generics.
+		return ResultType{}, nil
+	}
 	taggedFields := pass.ResultOf[fieldtags.Analyzer].(fieldtags.ResultType)
 	ssaInput := pass.ResultOf[buildssa.Analyzer].(*buildssa.SSA)
 

internal/pkg/source/analyzer.go

@@ -23,6 +23,7 @@ import (
 	"github.com/google/go-flow-levee/internal/pkg/fieldtags"
 	"golang.org/x/tools/go/analysis"
 	"golang.org/x/tools/go/analysis/passes/buildssa"
+	"golang.org/x/tools/go/analysis/passes/usesgenerics"
 	"golang.org/x/tools/go/ssa"
 )
 
@@ -33,11 +34,16 @@ var Analyzer = &analysis.Analyzer{
 	Doc:        "This analyzer identifies ssa.Values that are sources.",
 	Flags:      config.FlagSet,
 	Run:        run,
-	Requires:   []*analysis.Analyzer{buildssa.Analyzer, fieldtags.Analyzer, fieldpropagator.Analyzer},
+	Requires:   []*analysis.Analyzer{buildssa.Analyzer, fieldtags.Analyzer, fieldpropagator.Analyzer, usesgenerics.Analyzer},
 	ResultType: reflect.TypeOf(new(ResultType)).Elem(),
 }
 
 func run(pass *analysis.Pass) (interface{}, error) {
+	if r := pass.ResultOf[usesgenerics.Analyzer].(*usesgenerics.Result); r.Transitive != 0 {
+		// Generics are not supported yet (https://github.com/google/go-flow-levee/issues/323).
+		// TODO: Remove this check once the analyzers support generics.
+		return map[*ssa.Function][]*Source{}, nil
+	}
 	ssaInput := pass.ResultOf[buildssa.Analyzer].(*buildssa.SSA)
 	taggedFields := pass.ResultOf[fieldtags.Analyzer].(fieldtags.ResultType)
 	fieldPropagators := pass.ResultOf[fieldpropagator.Analyzer].(fieldpropagator.ResultType)