Rollup merge of #125100 - compiler-errors:faster, r=nnethercote

Don't do post-method-probe error reporting steps if we're in a suggestion
Currently in method probing, if we fail to pick a method, then we reset and try to collect relevant candidates for method errors:
https://github.com/rust-lang/rust/blob/34582118afaf00b0eb2d209a90b181c7156b501c/compiler/rustc_hir_typeck/src/method/probe.rs#L953-L993
However, we do method lookups via `lookup_method_for_diagnostic` and only care about the result if the method probe was a *success*.
Namely, we don't need to do a bunch of other lookups on failure, since we throw away these results anyways, such as an expensive call to:
https://github.com/rust-lang/rust/blob/34582118afaf00b0eb2d209a90b181c7156b501c/compiler/rustc_hir_typeck/src/method/probe.rs#L959
And:
https://github.com/rust-lang/rust/blob/34582118afaf00b0eb2d209a90b181c7156b501c/compiler/rustc_hir_typeck/src/method/probe.rs#L985
---
This PR also renames some methods so it's clear that they're for diagnostics.
r? `@nnethercote`

Author: compiler-errors

compiler/rustc_hir_typeck/src/demand.rs

@@ -938,14 +938,14 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 );
 }
 
-pubfnget_conversion_methods(
+pubfnget_conversion_methods_for_diagnostic(
 &self,
 span:Span,
 expected:Ty<'tcx>,
 checked_ty:Ty<'tcx>,
 hir_id: hir::HirId,
 ) -> Vec<AssocItem>{
-let methods = self.probe_for_return_type(
+let methods = self.probe_for_return_type_for_diagnostic(
  span,
  probe::Mode::MethodCall,
  expected,

compiler/rustc_hir_typeck/src/expr.rs

@@ -2414,7 +2414,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
 let guar = if field.name == kw::Empty{
 self.dcx().span_delayed_bug(field.span,"field name with no name")
-}elseifself.method_exists(field, base_ty, expr.hir_id, expected.only_has_type(self)){
+}elseifself.method_exists_for_diagnostic(
+ field,
+ base_ty,
+ expr.hir_id,
+ expected.only_has_type(self),
+){
 self.ban_take_value_of_method(expr, base_ty, field)
 }elseif !base_ty.is_primitive_ty(){
 self.ban_nonexisting_field(field, base, expr, base_ty)
@@ -2600,7 +2605,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 letmut err = self.private_field_err(field, base_did);
 
 // Also check if an accessible method exists, which is often what is meant.
-ifself.method_exists(field, expr_t, expr.hir_id, return_ty)
+ifself.method_exists_for_diagnostic(field, expr_t, expr.hir_id, return_ty)
  && !self.expr_in_place(expr.hir_id)
 {
 self.suggest_method_call(

compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs

@@ -290,7 +290,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 expected_ty_expr:Option<&'tcx hir::Expr<'tcx>>,
 ) -> bool{
 let expr = expr.peel_blocks();
-let methods = self.get_conversion_methods(expr.span, expected, found, expr.hir_id);
+let methods =
+self.get_conversion_methods_for_diagnostic(expr.span, expected, found, expr.hir_id);
 
 ifletSome((suggestion, msg, applicability, verbose, annotation)) =
 self.suggest_deref_or_ref(expr, found, expected)

compiler/rustc_hir_typeck/src/method/mod.rs

@@ -91,7 +91,7 @@ pub enum CandidateSource {
 impl<'a,'tcx>FnCtxt<'a,'tcx>{
 /// Determines whether the type `self_ty` supports a visible method named `method_name` or not.
 #[instrument(level = "debug", skip(self))]
-pubfnmethod_exists(
+pubfnmethod_exists_for_diagnostic(
 &self,
 method_name:Ident,
 self_ty:Ty<'tcx>,
@@ -102,7 +102,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
  probe::Mode::MethodCall,
  method_name,
  return_type,
-IsSuggestion(false),
+IsSuggestion(true),
  self_ty,
  call_expr_id,
 ProbeScope::TraitsInScope,

compiler/rustc_hir_typeck/src/method/probe.rs

@@ -90,6 +90,11 @@ pub(crate) struct ProbeContext<'a, 'tcx> {
 >,
 
 scope_expr_id:HirId,
+
+/// Is this probe being done for a diagnostic? This will skip some error reporting
+/// machinery, since we don't particularly care about, for example, similarly named
+/// candidates if we're *reporting* similarly named candidates.
+is_suggestion:IsSuggestion,
 }
 
 impl<'a,'tcx>DerefforProbeContext<'a,'tcx>{
@@ -220,7 +225,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 /// would use to decide if a method is a plausible fit for
 /// ambiguity purposes).
 #[instrument(level = "debug", skip(self, candidate_filter))]
-pubfnprobe_for_return_type(
+pubfnprobe_for_return_type_for_diagnostic(
 &self,
 span:Span,
 mode:Mode,
@@ -459,6 +464,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 &orig_values,
  steps.steps,
  scope_expr_id,
+ is_suggestion,
 );
 
  probe_cx.assemble_inherent_candidates();
@@ -553,6 +559,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 orig_steps_var_values:&'aOriginalQueryValues<'tcx>,
 steps:&'tcx[CandidateStep<'tcx>],
 scope_expr_id:HirId,
+is_suggestion:IsSuggestion,
 ) -> ProbeContext<'a,'tcx>{
 ProbeContext{
  fcx,
@@ -570,6 +577,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 static_candidates:RefCell::new(Vec::new()),
 unsatisfied_predicates:RefCell::new(Vec::new()),
  scope_expr_id,
+ is_suggestion,
 }
 }
 
@@ -944,6 +952,18 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 return r;
 }
 
+// If it's a `lookup_probe_for_diagnostic`, then quit early. No need to
+// probe for other candidates.
+ifself.is_suggestion.0{
+returnErr(MethodError::NoMatch(NoMatchData{
+static_candidates:vec![],
+unsatisfied_predicates:vec![],
+out_of_scope_traits:vec![],
+similar_candidate:None,
+mode:self.mode,
+}));
+}
+
 debug!("pick: actual search failed, assemble diagnostics");
 
 let static_candidates = std::mem::take(self.static_candidates.get_mut());
@@ -1631,6 +1651,7 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
 self.orig_steps_var_values,
 self.steps,
 self.scope_expr_id,
+IsSuggestion(true),
 );
  pcx.allow_similar_names = true;
  pcx.assemble_inherent_candidates();

compiler/rustc_hir_typeck/src/method/suggest.rs

@@ -2841,7 +2841,8 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 Some(output_ty) => self.resolve_vars_if_possible(output_ty),
  _ => return,
 };
-let method_exists = self.method_exists(item_name, output_ty, call.hir_id, return_type);
+let method_exists =
+self.method_exists_for_diagnostic(item_name, output_ty, call.hir_id, return_type);
 debug!("suggest_await_before_method: is_method_exist={}", method_exists);
 if method_exists {
  err.span_suggestion_verbose(

tests/ui/methods/probe-for-diagnostic-doesnt-do-extra-work.rs

@@ -0,0 +1,163 @@
+#![allow(non_snake_case)]
+
+// Ensures that we don't spend an unnecessary amount of compiler time building
+// suggestions for mistyped methods. This used to happen because when we had method
+// lookup failures, we would do subsequent method lookups, and those would themselves
+// do extra work that was unnecessary for the purposes of suggestions.
+// Fixed by #125100.
+
+macro_rules! traits {
+($($name:ident),*) => {
+ $(
+trait $name {
+fn $name(&self);
+}
+)*
+}
+}
+
+traits!(
+A0,A1,A2,A3,A4,A5,A6,A7,A8,A9,A10,A11,A12,A13,A14,A15,A16,A17,A18,A19,A20,
+A21,A22,A23,A24,A25,A26,A27,A28,A29,A30,A31,A32,A33,A34,A35,A36,A37,A38,A39,
+A40,A41,A42,A43,A44,A45,A46,A47,A48,A49,A50,A51,A52,A53,A54,A55,A56,A57,A58,
+A59,A60,A61,A62,A63,A64,A65,A66,A67,A68,A69,A70,A71,A72,A73,A74,A75,A76,A77,
+A78,A79,A80,A81,A82,A83,A84,A85,A86,A87,A88,A89,A90,A91,A92,A93,A94,A95,A96,
+A97,A98,A99,A100,A101,A102,A103,A104,A105,A106,A107,A108,A109,A110,A111,A112,
+A113,A114,A115,A116,A117,A118,A119,A120,A121,A122,A123,A124,A125,A126,A127,A128,
+A129,A130,A131,A132,A133,A134,A135,A136,A137,A138,A139,A140,A141,A142,A143,A144,
+A145,A146,A147,A148,A149,A150,A151,A152,A153,A154,A155,A156,A157,A158,A159,A160,
+A161,A162,A163,A164,A165,A166,A167,A168,A169,A170,A171,A172,A173,A174,A175,A176,
+A177,A178,A179,A180,A181,A182,A183,A184,A185,A186,A187,A188,A189,A190,A191,A192,
+A193,A194,A195,A196,A197,A198,A199,A200,A201,A202,A203,A204,A205,A206,A207,A208,
+A209,A210,A211,A212,A213,A214,A215,A216,A217,A218,A219,A220,A221,A222,A223,A224,
+A225,A226,A227,A228,A229,A230,A231,A232,A233,A234,A235,A236,A237,A238,A239,A240,
+A241,A242,A243,A244,A245,A246,A247,A248,A249,A250,A251,A252,A253,A254,A255,A256,
+A257,A258,A259,A260,A261,A262,A263,A264,A265,A266,A267,A268,A269,A270,A271,A272,
+A273,A274,A275,A276,A277,A278,A279,A280,A281,A282,A283,A284,A285,A286,A287,A288,
+A289,A290,A291,A292,A293,A294,A295,A296,A297,A298,A299,A300,A301,A302,A303,A304,
+A305,A306,A307,A308,A309,A310,A311,A312,A313,A314,A315,A316,A317,A318,A319,A320,
+A321,A322,A323,A324,A325,A326,A327,A328,A329,A330,A331,A332,A333,A334,A335,A336,
+A337,A338,A339,A340,A341,A342,A343,A344,A345,A346,A347,A348,A349,A350,A351,A352,
+A353,A354,A355,A356,A357,A358,A359,A360,A361,A362,A363,A364,A365,A366,A367,A368,
+A369,A370,A371,A372,A373,A374,A375,A376,A377,A378,A379,A380,A381,A382,A383,A384,
+A385,A386,A387,A388,A389,A390,A391,A392,A393,A394,A395,A396,A397,A398,A399,A400,
+A401,A402,A403,A404,A405,A406,A407,A408,A409,A410,A411,A412,A413,A414,A415,A416,
+A417,A418,A419,A420,A421,A422,A423,A424,A425,A426,A427,A428,A429,A430,A431,A432,
+A433,A434,A435,A436,A437,A438,A439,A440,A441,A442,A443,A444,A445,A446,A447,A448,
+A449,A450,A451,A452,A453,A454,A455,A456,A457,A458,A459,A460,A461,A462,A463,A464,
+A465,A466,A467,A468,A469,A470,A471,A472,A473,A474,A475,A476,A477,A478,A479,A480,
+A481,A482,A483,A484,A485,A486,A487,A488,A489,A490,A491,A492,A493,A494,A495,A496,
+A497,A498,A499,A500,A501,A502,A503,A504,A505,A506,A507,A508,A509,A510,A511,A512,
+A513,A514,A515,A516,A517,A518,A519,A520,A521,A522,A523,A524,A525,A526,A527,A528,
+A529,A530,A531,A532,A533,A534,A535,A536,A537,A538,A539,A540,A541,A542,A543,A544,
+A545,A546,A547,A548,A549,A550,A551,A552,A553,A554,A555,A556,A557,A558,A559,A560,
+A561,A562,A563,A564,A565,A566,A567,A568,A569,A570,A571,A572,A573,A574,A575,A576,
+A577,A578,A579,A580,A581,A582,A583,A584,A585,A586,A587,A588,A589,A590,A591,A592,
+A593,A594,A595,A596,A597,A598,A599,A600,A601,A602,A603,A604,A605,A606,A607,A608,
+A609,A610,A611,A612,A613,A614,A615,A616,A617,A618,A619,A620,A621,A622,A623,A624,
+A625,A626,A627,A628,A629,A630,A631,A632,A633,A634,A635,A636,A637,A638,A639,A640,
+A641,A642,A643,A644,A645,A646,A647,A648,A649,A650,A651,A652,A653,A654,A655,A656,
+A657,A658,A659,A660,A661,A662,A663,A664,A665,A666,A667,A668,A669,A670,A671,A672,
+A673,A674,A675,A676,A677,A678,A679,A680,A681,A682,A683,A684,A685,A686,A687,A688,
+A689,A690,A691,A692,A693,A694,A695,A696,A697,A698,A699,A700,A701,A702,A703,A704,
+A705,A706,A707,A708,A709,A710,A711,A712,A713,A714,A715,A716,A717,A718,A719,A720,
+A721,A722,A723,A724,A725,A726,A727,A728,A729,A730,A731,A732,A733,A734,A735,A736,
+A737,A738,A739,A740,A741,A742,A743,A744,A745,A746,A747,A748,A749,A750,A751,A752,
+A753,A754,A755,A756,A757,A758,A759,A760,A761,A762,A763,A764,A765,A766,A767,A768,
+A769,A770,A771,A772,A773,A774,A775,A776,A777,A778,A779,A780,A781,A782,A783,A784,
+A785,A786,A787,A788,A789,A790,A791,A792,A793,A794,A795,A796,A797,A798,A799,A800,
+A801,A802,A803,A804,A805,A806,A807,A808,A809,A810,A811,A812,A813,A814,A815,A816,
+A817,A818,A819,A820,A821,A822,A823,A824,A825,A826,A827,A828,A829,A830,A831,A832,
+A833,A834,A835,A836,A837,A838,A839,A840,A841,A842,A843,A844,A845,A846,A847,A848,
+A849,A850,A851,A852,A853,A854,A855,A856,A857,A858,A859,A860,A861,A862,A863,A864,
+A865,A866,A867,A868,A869,A870,A871,A872,A873,A874,A875,A876,A877,A878,A879,A880,
+A881,A882,A883,A884,A885,A886,A887,A888,A889,A890,A891,A892,A893,A894,A895,A896,
+A897,A898,A899,A900,A901,A902,A903,A904,A905,A906,A907,A908,A909,A910,A911,A912,
+A913,A914,A915,A916,A917,A918,A919,A920,A921,A922,A923,A924,A925,A926,A927,A928,
+A929,A930,A931,A932,A933,A934,A935,A936,A937,A938,A939,A940,A941,A942,A943,A944,
+A945,A946,A947,A948,A949,A950,A951,A952,A953,A954,A955,A956,A957,A958,A959,A960,
+A961,A962,A963,A964,A965,A966,A967,A968,A969,A970,A971,A972,A973,A974,A975,A976,
+A977,A978,A979,A980,A981,A982,A983,A984,A985,A986,A987,A988,A989,A990,A991,A992,
+A993,A994,A995,A996,A997,A998,A999
+);
+
+#[derive(Default)]
+structM0{
+m1:M1,
+m2:M1,
+m3:M1,
+m4:M1,
+m5:M1,
+m6:M1,
+m7:M1,
+m8:M1,
+m9:M1,
+m10:M1,
+m11:M1,
+m12:M1,
+m13:M1,
+m14:M1,
+m15:M1,
+}
+
+#[derive(Default)]
+structM1{
+m1:M2,
+m2:M2,
+m3:M2,
+m4:M2,
+m5:M2,
+m6:M2,
+m7:M2,
+m8:M2,
+m9:M2,
+m10:M2,
+m11:M2,
+m12:M2,
+m13:M2,
+m14:M2,
+m15:M2,
+}
+
+#[derive(Default)]
+structM2{
+m1:M3,
+m2:M3,
+m3:M3,
+m4:M3,
+m5:M3,
+m6:M3,
+m7:M3,
+m8:M3,
+m9:M3,
+m10:M3,
+m11:M3,
+m12:M3,
+m13:M3,
+m14:M3,
+m15:M3,
+}
+
+#[derive(Default)]
+structM3{}
+
+fnmain(){
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+M0::default().Au();
+//~^ ERROR no method named `Au` found for struct `M0` in the current scope
+}

tests/ui/methods/probe-for-diagnostic-doesnt-do-extra-work.stderr

@@ -0,0 +1,84 @@
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:145:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:147:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:149:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:151:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:153:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:155:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:157:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:159:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error[E0599]: no method named `Au` found for struct `M0` in the current scope
+ --> $DIR/probe-for-diagnostic-doesnt-do-extra-work.rs:161:19
+ |
+LL | struct M0 {
+ | --------- method `Au` not found for this struct
+...
+LL | M0::default().Au();
+ | ^^ method not found in `M0`
+
+error: aborting due to 9 previous errors
+
+For more information about this error, try `rustc --explain E0599`.