Add warnings for shadowed @GDScriptand @GlobalScope functions

[EdwardChanCH]

Closes: godotengine/godot-proposals#14425

Related: #106984

Note: Some previous code has been split into #117308 to keep this PR manageable.

Any help is appreciated!

[EdwardChanCH]

Discovered more bugs:

• When hovering over the middle of a named lambda name, the tooltip is shown only for @GDScript functions.
• When hovering over the left edge of a named lambda name, the tooltip is shown for native, @GDScript, @GlobalScope, and local functions.
  • The GDScript parser is incorrect. Reported in
    Incorrect auto-completion and tooltip for named lambda #117305.
• When hovering over the middle of a function name, the tooltip is shown only for native and @GDScript functions.
• When hovering over the left edge of a function name, the tooltip is shown only for native and @GDScript functions.

Edit: Fixed.

[EdwardChanCH]

Thanks for removing the 29 extra team reviews, not sure what happened there...

[EdwardChanCH]

Below is a full summary of what this PR fixed:

@warning_ignore_start("unused_parameter", "unused_variable", "unused_signal", "untyped_declaration", "inferred_declaration")

class_name ceil # Missing warning. <-- Too complex to fix in this PR.
extends Node

class floor extends Node: # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
	func f() -> void:
		pass

var sin = 111 # (SHADOWED_GLOBAL_IDENTIFIER)
const cos = 222 # (SHADOWED_GLOBAL_IDENTIFIER)

# Named enum identifier do not shadow anything, because it can only be accessed as NamedEnum.EnumIdentifier.

enum max { # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
	min = 333 # No warning as expected.
}

enum {
	clamp,       # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
	clampi = 444 # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
}

# Note: Signal parameter do not shadow anything.

signal sqrt # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)

signal s(pow) # No warning as expected.

func get(_property: StringName) -> Variant: # (NATIVE_METHOD_OVERRIDE)
	return 100

func char(code :int): # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
	return 200

func log(x: float): # Missing warning. <-- Fixed! Now warns (SHADOWED_GLOBAL_IDENTIFIER)
	return 300

func unique(log: float): # (SHADOWED_GLOBAL_IDENTIFIER)
	return 400

func unique2(...log): # (SHADOWED_GLOBAL_IDENTIFIER)
	return 500

# Note: Named lambdas do not override anything.

# No warning as expected.
var named_lambda_1 = func get():
	return null

# No warning as expected.
var named_lambda_2 = func char():
	return null

# No warning as expected.
var named_lambda_3 = func log():
	return null

var named_lambda_4 = func unique():
	return null

func _ready() -> void:
	var sinh = 1 # (SHADOWED_GLOBAL_IDENTIFIER)
	
	for char in []: # (SHADOWED_GLOBAL_IDENTIFIER)
		pass
	
	var k = 1
	match k:
		var abs: # (SHADOWED_GLOBAL_IDENTIFIER)
			pass
	
	# The new warnings are consistent with how GDScript is parsed.
	print(sin) # Prints 111
	print(cos) # Prints 222
	print(max) # Prints { "min": 333 }
	print(min) # Prints @GlobalScope::min
	print(max.min) # Prints 333
	print(clamp) # Prints 0
	print(clampi) # Prints 444
	print(ceil) # Prints (res://main.gd):<GDScript#-9223372002226600493>
	print(floor) # Prints ():<GDScript#-9223372002042051115>
	print(sqrt) # Prints Node(main.gd)::[signal]sqrt
	print(s) # Prints Node(main.gd)::[signal]s

[EdwardChanCH]

class_name ceil # Missing warning. <-- Too complex to fix in this PR.

Fixing this (in the future) will require changing GDScriptAnalyzer::is_shadowing(), since it detects the current script's class_name as a global identifier.