FIR: add equality call checker

Added checker for FirEqualityOperatorCall. It's surfaced as one of the
following diagnostics depending on the PSI structure and types under
comparison:

* INCOMPATIBLE_TYPES(_WARNING)
* EQUALITY_NOT_APPLICABLE(_WARNING)
* INCOMPATIBLE_ENUM_COMPARISON_ERROR

Comparing with FE1.0, the current implementation is more conservative
and only highlights error if the types are known to follow certain
contracts with `equals` method. Otherwise, the checker reports warnings
instead.

However, the current checker is more strict in the following situations:
1. it now rejects incompatible enum types like `Enum<E1>` and
  `Enum<E2>`, which was previously accepted
2. it now rejects incompatible class types like `Class<String>` and
  `Class<Int>`, which was previously accepted
3. the check now takes smart cast into consideration, so
  `if (x is String) x == 3` is now rejected

This commit is contained in:

Tianyu Geng

2021-04-02 20:49:50 -07:00

committed by

teamcityserver

parent 787c743333

commit 7bb81ef157

43 changed files with 1218 additions and 188 deletions

									
										compiler/testData/diagnostics/tests/BinaryCallsOnNullableValues.fir.kt
									
Vendored

		+3
		-3
	
												View File
												
				@@ -14,10 +14,10 @@ fun f(): Unit {

				    x == 1

				    x != 1

				    A() == 1

				    <!EQUALITY_NOT_APPLICABLE!>A() == 1<!>

				    x === "1"

				    x !== "1"

				    <!EQUALITY_NOT_APPLICABLE!>x === "1"<!>

				    <!EQUALITY_NOT_APPLICABLE!>x !== "1"<!>

				    x === 1

				    x !== 1