Parse type variables of local functions before return type.

pkg/front_end/lib/src/fasta/kernel/body_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/body_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
index 720ed79084120164a6a5bff99955b66967bcdef7..afbab2f12293ecf3286cf09fbe8c8de4599587df 100644
--- a/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/body_builder.dart
@@ -2490,11 +2490,6 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
       exitLocalScope();
     }
     FormalParameters formals = pop();
-    List<TypeParameter> typeParameters = typeVariableBuildersToKernel(pop());
-    FunctionNode function = formals.addToFunction(new FunctionNode(body,
-        typeParameters: typeParameters, asyncMarker: asyncModifier)
-      ..fileOffset = formals.charOffset
-      ..fileEndOffset = token.charOffset);
     exitLocalScope();
     var declaration = pop();
     var returnType = pop();
@@ -2502,6 +2497,11 @@ class BodyBuilder extends ScopeListener<JumpTarget> implements BuilderHelper {
     returnType ??= const DynamicType();
     pop(); // Modifiers.
     exitFunction();
+    List<TypeParameter> typeParameters = typeVariableBuildersToKernel(pop());
+    FunctionNode function = formals.addToFunction(new FunctionNode(body,
+        typeParameters: typeParameters, asyncMarker: asyncModifier)
+      ..fileOffset = formals.charOffset
+      ..fileEndOffset = token.charOffset);
     if (declaration is FunctionDeclaration) {
       KernelFunctionDeclaration.setHasImplicitReturnType(
           declaration, hasImplicitReturnType);