GDScript: Disallow type inference with untyped initializer

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_local_variable.gd

@@ -0,0 +1,3 @@
+func test():
+	var untyped = 1
+	var inferred := untyped

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_local_variable.out

@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Cannot infer the type of "inferred" variable because the value doesn't have a set type.

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_member_variable.gd

@@ -0,0 +1,5 @@
+var untyped = 1
+var inferred := untyped
+
+func test():
+	pass

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_member_variable.out

@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Cannot infer the type of "inferred" variable because the value doesn't have a set type.

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_parameter.gd

@@ -0,0 +1,5 @@
+func check(untyped = 1, inferred := untyped):
+	pass
+
+func test():
+	check()

modules/gdscript/tests/scripts/analyzer/errors/inferring_with_weak_type_parameter.out

@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Cannot infer the type of "inferred" parameter because the value doesn't have a set type.