update always_specify_types to lint generic methods

lib/src/rules/always_specify_types.dart

@@ -93,6 +93,7 @@ class AlwaysSpecifyTypes extends LintRule implements NodeLintRule {
     registry.addDeclaredIdentifier(this, visitor);
     registry.addListLiteral(this, visitor);
     registry.addMapLiteral(this, visitor);
+    registry.addMethodInvocation(this, visitor);
     registry.addSimpleFormalParameter(this, visitor);
     registry.addTypeName(this, visitor);
     registry.addVariableDeclarationList(this, visitor);
@@ -164,4 +165,16 @@ class _Visitor extends SimpleAstVisitor<void> {
       rule.reportLintForToken(list.keyword);
     }
   }
+
+  @override
+  void visitMethodInvocation(MethodInvocation node) {
+    if (node.typeArguments == null) {
+      final element = node.methodName.bestElement;
+      if (element is FunctionTypedElement &&
+          element.typeParameters.isNotEmpty &&
+          !element.metadata.any((a) => _isOptionalTypeArgs(a.element))) {
+        rule.reportLint(node.methodName);
+      }
+    }
+  }
 }

test/rules/always_specify_types.dart

@@ -100,3 +100,17 @@ void m() {
      print("won't happen");
   }
 }
+
+class A {
+  m1<T>() {}
+  @optionalTypeArgs
+  m2<T>() {}
+
+  m() {
+    A a;
+    a.m1(); // LINT
+    a.m1<int>(); // OK
+    a.m2(); // OK
+    a.m2<int>(); // OK
+  }
+}