GDScript: Fix typing of lambda functions

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

@@ -0,0 +1,4 @@
+func test():
+	var lambda := func() -> int:
+		print('no return')
+	lambda.call()

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

@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Not all code paths return a value.

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

@@ -0,0 +1,4 @@
+func test():
+	var lambda := func() -> int:
+		return 'string'
+	print(lambda.call())

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

@@ -0,0 +1,2 @@
+GDTEST_ANALYZER_ERROR
+Cannot return value of type "String" because the function return type is "int".

modules/gdscript/tests/scripts/analyzer/features/lambda_typed.gd

@@ -0,0 +1,12 @@
+func test():
+	var lambda_0 := func() -> void:
+		print(0)
+	lambda_0.call()
+
+	var lambda_1 := func(printed: int) -> void:
+		print(printed)
+	lambda_1.call(1)
+
+	var lambda_2 := func(identity: int) -> int:
+		return identity
+	print(lambda_2.call(2))

modules/gdscript/tests/scripts/analyzer/features/lambda_typed.out

@@ -0,0 +1,4 @@
+GDTEST_OK
+0
+1
+2

modules/gdscript/tests/scripts/analyzer/warnings/lambda_shadowing_arg.gd

@@ -0,0 +1,6 @@
+var shadow: int
+
+func test():
+	var lambda := func(shadow: String) -> void:
+		print(shadow)
+	lambda.call('shadow')

modules/gdscript/tests/scripts/analyzer/warnings/lambda_shadowing_arg.out

@@ -0,0 +1,6 @@
+GDTEST_OK
+>> WARNING
+>> Line: 4
+>> SHADOWED_VARIABLE
+>> The local function parameter "shadow" is shadowing an already-declared variable at line 1.
+shadow

modules/gdscript/tests/scripts/analyzer/warnings/lambda_unused_arg.gd

@@ -0,0 +1,4 @@
+func test():
+	var lambda := func(unused: Variant) -> void:
+		pass
+	lambda.call()

modules/gdscript/tests/scripts/analyzer/warnings/lambda_unused_arg.out

@@ -0,0 +1,5 @@
+GDTEST_OK
+>> WARNING
+>> Line: 2
+>> UNUSED_PARAMETER
+>>