From 67ec59003a9392052b70d2b36f23c4108d2e4b5c Mon Sep 17 00:00:00 2001
From: Grant Nelson <grant.nelson@workiva.com>
Date: Wed, 2 Oct 2024 16:23:24 -0600
Subject: [PATCH] Adding more tests around IndexExpr case

---
 compiler/internal/analysis/info.go      |  5 +++
 compiler/internal/analysis/info_test.go | 44 ++++++++++++++++++++++++-
 internal/srctesting/srctesting.go       |  2 +-
 3 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/compiler/internal/analysis/info.go b/compiler/internal/analysis/info.go
index 4a2e50078..4d83a6c04 100644
--- a/compiler/internal/analysis/info.go
+++ b/compiler/internal/analysis/info.go
@@ -356,6 +356,11 @@ func (fi *FuncInfo) visitCallExpr(n *ast.CallExpr) ast.Visitor {
 		// Register literal function call site in case it is identified as blocking.
 		fi.literalFuncCallees[f] = append(fi.literalFuncCallees[f], fi.visitorStack.copy())
 		return nil // No need to walk under this CallExpr, we already did it manually.
+	case *ast.IndexExpr:
+		// Collect info about the instantiated type or function.
+
+		fmt.Printf(">> %[1]T %#[1]v\n", n) // TODO(gn): Finish implementing!
+
 	default:
 		if astutil.IsTypeExpr(f, fi.pkgInfo.Info) {
 			// This is a type conversion, not a call. Type assertion itself is not
diff --git a/compiler/internal/analysis/info_test.go b/compiler/internal/analysis/info_test.go
index 7573fcb4c..cb567bf0a 100644
--- a/compiler/internal/analysis/info_test.go
+++ b/compiler/internal/analysis/info_test.go
@@ -55,7 +55,7 @@ func TestInstanceBlocking(t *testing.T) {
 		notBlocking []string
 	}{
 		{
-			name: "blocking instance",
+			name: `blocking instance`,
 			src: `package test
 				func blocking[T any]() {
 					c := make(chan T)
@@ -73,6 +73,48 @@ func TestInstanceBlocking(t *testing.T) {
 			blocking:    []string{`blocking`, `bInt`},
 			notBlocking: []string{`notBlocking`, `nbUint`},
 		},
+		{
+			name: `differentiate indexing`,
+			// Below calls notBlocking but since the function pointers
+			// are in the slice they will both be considered as blocking.
+			// This is just checking that the analysis can tell between
+			// indexing and instantiation of a generic.
+			src: `package test
+				func blocking() {
+					c := make(chan int)
+					<-c
+				}
+				func notBlocking() {
+					println()
+				}
+				var funcs = []func() { blocking, notBlocking }
+				func indexer() {
+					funcs[1]()
+				}`,
+			blocking:    []string{`blocking`, `indexer`},
+			notBlocking: []string{`notBlocking`},
+		},
+		{
+			name: `differentiate casting`,
+			// Below checks that casting to an instance type is treated as a
+			// cast an not accidentally treated as a function call.
+			src: `package test
+				type Foo[T any] interface {
+					Baz() T
+				}
+				type Bar struct {
+					name string
+				}
+				func (b Bar) Baz() string {
+					return b.name
+				}
+				func caster() {
+					a := Bar{"foo"}
+					b := Foo[string](a)
+					println(b.Baz())
+				}`,
+			notBlocking: []string{`caster`},
+		},
 	}
 
 	for _, test := range tests {
diff --git a/internal/srctesting/srctesting.go b/internal/srctesting/srctesting.go
index a74d31958..6bba9fced 100644
--- a/internal/srctesting/srctesting.go
+++ b/internal/srctesting/srctesting.go
@@ -71,7 +71,7 @@ func (f *Fixture) Check(importPath string, files ...*ast.File) (*types.Info, *ty
 	}
 	pkg, err := config.Check(importPath, f.FileSet, files, info)
 	if err != nil {
-		f.T.Fatalf("Filed to type check test source: %s", err)
+		f.T.Fatalf("Failed to type check test source: %s", err)
 	}
 	f.Packages[importPath] = pkg
 	return info, pkg