diff --git a/src/cmd/compile/internal/inline/inlheur/analyze.go b/src/cmd/compile/internal/inline/inlheur/analyze.go
index d3d6383ba8..727851b6a4 100644
--- a/src/cmd/compile/internal/inline/inlheur/analyze.go
+++ b/src/cmd/compile/internal/inline/inlheur/analyze.go
@@ -113,11 +113,11 @@ func computeFuncProps(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int
 		fmt.Fprintf(os.Stderr, "=-= starting analysis of func %v:\n%+v\n",
 			fn, fn)
 	}
-	ra := makeResultsAnalyzer(fn, canInline, inlineMaxBudget)
-	pa := makeParamsAnalyzer(fn)
-	ffa := makeFuncFlagsAnalyzer(fn)
-	analyzers := []propAnalyzer{ffa, ra, pa}
 	funcProps := new(FuncProps)
+	ffa := makeFuncFlagsAnalyzer(fn)
+	analyzers := []propAnalyzer{ffa}
+	analyzers = addResultsAnalyzer(fn, canInline, inlineMaxBudget, analyzers, funcProps)
+	analyzers = addParamsAnalyzer(fn, analyzers, funcProps)
 	runAnalyzersOnFunction(fn, analyzers)
 	for _, a := range analyzers {
 		a.setResults(funcProps)
diff --git a/src/cmd/compile/internal/inline/inlheur/analyze_func_params.go b/src/cmd/compile/internal/inline/inlheur/analyze_func_params.go
index f65d8909e0..0faa798eeb 100644
--- a/src/cmd/compile/internal/inline/inlheur/analyze_func_params.go
+++ b/src/cmd/compile/internal/inline/inlheur/analyze_func_params.go
@@ -29,10 +29,33 @@ func getParams(fn *ir.Func) []*ir.Name {
 	return fn.Dcl[:numParams]
 }
 
-func makeParamsAnalyzer(fn *ir.Func) *paramsAnalyzer {
+// addParamsAnalyzer creates a new paramsAnalyzer helper object for
+// the function fn, appends it to the analyzers list, and returns the
+// new list. If the function in question doesn't have any interesting
+// parameters then the analyzer list is returned unchanged, and the
+// params flags in "fp" are updated accordingly.
+func addParamsAnalyzer(fn *ir.Func, analyzers []propAnalyzer, fp *FuncProps) []propAnalyzer {
+	pa, props := makeParamsAnalyzer(fn)
+	if pa != nil {
+		analyzers = append(analyzers, pa)
+	} else {
+		fp.ParamFlags = props
+	}
+	return analyzers
+}
+
+// makeParamAnalyzer creates a new helper object to analyze parameters
+// of function fn. If the function doesn't have any interesting
+// params, a nil helper is returned along with a set of default param
+// flags for the func.
+func makeParamsAnalyzer(fn *ir.Func) (*paramsAnalyzer, []ParamPropBits) {
 	params := getParams(fn) // includes receiver if applicable
+	if len(params) == 0 {
+		return nil, nil
+	}
 	vals := make([]ParamPropBits, len(params))
 	top := make([]bool, len(params))
+	interestingToAnalyze := false
 	for i, pn := range params {
 		if pn == nil {
 			continue
@@ -48,6 +71,7 @@ func makeParamsAnalyzer(fn *ir.Func) *paramsAnalyzer {
 			continue
 		}
 		top[i] = true
+		interestingToAnalyze = true
 	}
 
 	if debugTrace&debugTraceParams != 0 {
@@ -63,13 +87,18 @@ func makeParamsAnalyzer(fn *ir.Func) *paramsAnalyzer {
 		}
 	}
 
-	return &paramsAnalyzer{
+	if !interestingToAnalyze {
+		return nil, vals
+	}
+
+	pa := &paramsAnalyzer{
 		fname:            fn.Sym().Name,
 		values:           vals,
 		params:           params,
 		top:              top,
 		condLevelTracker: new(condLevelTracker),
 	}
+	return pa, nil
 }
 
 func (pa *paramsAnalyzer) setResults(funcProps *FuncProps) {
diff --git a/src/cmd/compile/internal/inline/inlheur/analyze_func_returns.go b/src/cmd/compile/internal/inline/inlheur/analyze_func_returns.go
index 3ee249fa9d..5eac02a37e 100644
--- a/src/cmd/compile/internal/inline/inlheur/analyze_func_returns.go
+++ b/src/cmd/compile/internal/inline/inlheur/analyze_func_returns.go
@@ -12,10 +12,10 @@ import (
 	"os"
 )
 
-// returnsAnalyzer stores state information for the process of
+// resultsAnalyzer stores state information for the process of
 // computing flags/properties for the return values of a specific Go
 // function, as part of inline heuristics synthesis.
-type returnsAnalyzer struct {
+type resultsAnalyzer struct {
 	fname           string
 	props           []ResultPropBits
 	values          []resultVal
@@ -36,38 +36,66 @@ type resultVal struct {
 	derived bool // see deriveReturnFlagsFromCallee below
 }
 
-func makeResultsAnalyzer(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32) *returnsAnalyzer {
+// addResultsAnalyzer creates a new resultsAnalyzer helper object for
+// the function fn, appends it to the analyzers list, and returns the
+// new list. If the function in question doesn't have any returns (or
+// any interesting returns) then the analyzer list is left as is, and
+// the result flags in "fp" are updated accordingly.
+func addResultsAnalyzer(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32, analyzers []propAnalyzer, fp *FuncProps) []propAnalyzer {
+	ra, props := makeResultsAnalyzer(fn, canInline, inlineMaxBudget)
+	if ra != nil {
+		analyzers = append(analyzers, ra)
+	} else {
+		fp.ResultFlags = props
+	}
+	return analyzers
+}
+
+// makeResultsAnalyzer creates a new helper object to analyze results
+// in function fn. If the function doesn't have any interesting
+// results, a nil helper is returned along with a set of default
+// result flags for the func.
+func makeResultsAnalyzer(fn *ir.Func, canInline func(*ir.Func), inlineMaxBudget int32) (*resultsAnalyzer, []ResultPropBits) {
 	results := fn.Type().Results()
+	if len(results) == 0 {
+		return nil, nil
+	}
 	props := make([]ResultPropBits, len(results))
 	vals := make([]resultVal, len(results))
+	interestingToAnalyze := false
 	for i := range results {
 		rt := results[i].Type
 		if !rt.IsScalar() && !rt.HasNil() {
 			// existing properties not applicable here (for things
 			// like structs, arrays, slices, etc).
-			props[i] = ResultNoInfo
 			continue
 		}
 		// set the "top" flag (as in "top element of data flow lattice")
 		// meaning "we have no info yet, but we might later on".
 		vals[i].top = true
+		interestingToAnalyze = true
 	}
-	return &returnsAnalyzer{
+	if !interestingToAnalyze {
+		return nil, props
+	}
+
+	ra := &resultsAnalyzer{
 		props:           props,
 		values:          vals,
 		canInline:       canInline,
 		inlineMaxBudget: inlineMaxBudget,
 	}
+	return ra, nil
 }
 
 // setResults transfers the calculated result properties for this
 // function to 'funcProps'.
-func (ra *returnsAnalyzer) setResults(funcProps *FuncProps) {
+func (ra *resultsAnalyzer) setResults(funcProps *FuncProps) {
 	// Promote ResultAlwaysSameFunc to ResultAlwaysSameInlinableFunc
 	for i := range ra.values {
 		if ra.props[i] == ResultAlwaysSameFunc && !ra.values[i].derived {
 			f := ra.values[i].fn.Func
-			// If the function being returns is a closure that hasn't
+			// If the function being returned is a closure that hasn't
 			// yet been checked by CanInline, invoke it now. NB: this
 			// is hacky, it would be better if things were structured
 			// so that all closures were visited ahead of time.
@@ -78,11 +106,11 @@ func (ra *returnsAnalyzer) setResults(funcProps *FuncProps) {
 			}
 			// HACK: in order to allow for call site score
 			// adjustments, we used a relaxed inline budget in
-			// determining inlinability. Here what we want to know is
-			// whether the func in question is likely to be inlined,
-			// as opposed to whether it might possibly be inlined if
-			// all the right score adjustments happened, so check the
-			// cost here as well.
+			// determining inlinability. For the check below, however,
+			// we want to know is whether the func in question is
+			// likely to be inlined, as opposed to whether it might
+			// possibly be inlined if all the right score adjustments
+			// happened, so do a simple check based on the cost.
 			if f.Inl != nil && f.Inl.Cost <= ra.inlineMaxBudget {
 				ra.props[i] = ResultAlwaysSameInlinableFunc
 			}
@@ -91,16 +119,16 @@ func (ra *returnsAnalyzer) setResults(funcProps *FuncProps) {
 	funcProps.ResultFlags = ra.props
 }
 
-func (ra *returnsAnalyzer) pessimize() {
+func (ra *resultsAnalyzer) pessimize() {
 	for i := range ra.props {
 		ra.props[i] = ResultNoInfo
 	}
 }
 
-func (ra *returnsAnalyzer) nodeVisitPre(n ir.Node) {
+func (ra *resultsAnalyzer) nodeVisitPre(n ir.Node) {
 }
 
-func (ra *returnsAnalyzer) nodeVisitPost(n ir.Node) {
+func (ra *resultsAnalyzer) nodeVisitPost(n ir.Node) {
 	if len(ra.values) == 0 {
 		return
 	}
@@ -153,7 +181,7 @@ func isFuncName(n ir.Node) (*ir.Name, bool, bool) {
 // applies a dataflow "meet" operation to combine this result with any
 // previous result (for the given return slot) that we've already
 // processed.
-func (ra *returnsAnalyzer) analyzeResult(ii int, n ir.Node) {
+func (ra *resultsAnalyzer) analyzeResult(ii int, n ir.Node) {
 	isAllocMem := isAllocatedMem(n)
 	isConcConvItf := isConcreteConvIface(n)
 	lit, isConst := isLiteral(n)
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/acrosscall.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/acrosscall.go
index 464e47c5e8..9cd4abfaea 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/acrosscall.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/acrosscall.go
@@ -12,7 +12,7 @@ package params
 // ParamFlags
 //   0 ParamFeedsIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[8],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[8],"ResultFlags":null}
 // callsite: acrosscall.go:20:12|0 flagstr "" flagval 0 score 60 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -24,7 +24,7 @@ func T_feeds_indirect_call_via_call_toplevel(f func(int)) {
 // ParamFlags
 //   0 ParamMayFeedIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[16],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[16],"ResultFlags":null}
 // callsite: acrosscall.go:33:13|0 flagstr "" flagval 0 score 60 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -38,7 +38,7 @@ func T_feeds_indirect_call_via_call_conditional(f func(int)) {
 // ParamFlags
 //   0 ParamMayFeedIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[16],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[16],"ResultFlags":null}
 // callsite: acrosscall.go:46:23|0 flagstr "" flagval 0 score 64 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -50,7 +50,7 @@ func T_feeds_conditional_indirect_call_via_call_toplevel(f func(int)) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // callsite: acrosscall.go:58:9|0 flagstr "" flagval 0 score 8 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -62,7 +62,7 @@ func T_feeds_if_via_call(x int) {
 // ParamFlags
 //   0 ParamMayFeedIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[64],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[64],"ResultFlags":null}
 // callsite: acrosscall.go:71:10|0 flagstr "" flagval 0 score 8 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -76,7 +76,7 @@ func T_feeds_if_via_call_conditional(x int) {
 // ParamFlags
 //   0 ParamMayFeedIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[64],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[64],"ResultFlags":null}
 // callsite: acrosscall.go:84:20|0 flagstr "" flagval 0 score 12 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -89,7 +89,7 @@ func T_feeds_conditional_if_via_call(x int) {
 //   0 ParamFeedsIndirectCall|ParamMayFeedIndirectCall
 //   1 ParamFeedsIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[24,8],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[24,8],"ResultFlags":null}
 // callsite: acrosscall.go:100:23|1 flagstr "" flagval 0 score 64 mask 0 maskstr ""
 // callsite: acrosscall.go:101:12|2 flagstr "" flagval 0 score 60 mask 0 maskstr ""
 // callsite: acrosscall.go:99:12|0 flagstr "" flagval 0 score 60 mask 0 maskstr ""
@@ -105,7 +105,7 @@ func T_multifeeds(f1, f2 func(int)) {
 // ResultFlags
 //   0 ResultAlwaysSameConstant
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[8]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[8]}
 // callsite: acrosscall.go:113:24|0 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -117,7 +117,7 @@ func T_acrosscall_returnsconstant() int {
 // ResultFlags
 //   0 ResultIsAllocatedMem
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[2]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[2]}
 // callsite: acrosscall.go:125:19|0 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
@@ -129,7 +129,7 @@ func T_acrosscall_returnsmem() *int {
 // ResultFlags
 //   0 ResultIsConcreteTypeConvertedToInterface
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[4]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[4]}
 // callsite: acrosscall.go:137:19|0 flagstr "" flagval 0 score 7 mask 0 maskstr ""
 // <endcallsites>
 // <endfuncpreamble>
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/calls.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/calls.go
index 4efc3c4003..c87e290947 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/calls.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/calls.go
@@ -12,7 +12,7 @@ import "os"
 
 // calls.go T_call_in_panic_arg 19 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // callsite: calls.go:21:15|0 flagstr "CallSiteOnPanicPath" flagval 2 score 42 mask 1 maskstr "panicPathAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -24,7 +24,7 @@ func T_call_in_panic_arg(x int) {
 
 // calls.go T_calls_in_loops 32 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // callsite: calls.go:34:9|0 flagstr "CallSiteInLoop" flagval 1 score -3 mask 4 maskstr "inLoopAdj"
 // callsite: calls.go:37:9|1 flagstr "CallSiteInLoop" flagval 1 score -3 mask 4 maskstr "inLoopAdj"
 // <endcallsites>
@@ -40,7 +40,7 @@ func T_calls_in_loops(x int, q []string) {
 
 // calls.go T_calls_in_pseudo_loop 48 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // callsite: calls.go:50:9|0 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // callsite: calls.go:54:9|1 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // <endcallsites>
@@ -58,7 +58,7 @@ func T_calls_in_pseudo_loop(x int, q []string) {
 
 // calls.go T_calls_on_panic_paths 67 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // callsite: calls.go:69:9|0 flagstr "CallSiteOnPanicPath" flagval 2 score 42 mask 1 maskstr "panicPathAdj"
 // callsite: calls.go:73:9|1 flagstr "CallSiteOnPanicPath" flagval 2 score 42 mask 1 maskstr "panicPathAdj"
 // callsite: calls.go:77:12|2 flagstr "CallSiteOnPanicPath" flagval 2 score 102 mask 1 maskstr "panicPathAdj"
@@ -83,7 +83,7 @@ func T_calls_on_panic_paths(x int, q []string) {
 //   0 ParamFeedsIfOrSwitch|ParamMayFeedIfOrSwitch
 //   1 ParamNoInfo
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[96,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[96,0],"ResultFlags":null}
 // callsite: calls.go:103:9|0 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // callsite: calls.go:112:9|1 flagstr "" flagval 0 score 2 mask 0 maskstr ""
 // callsite: calls.go:115:9|2 flagstr "" flagval 0 score 2 mask 0 maskstr ""
@@ -122,7 +122,7 @@ func T_calls_not_on_panic_paths(x int, q []string) {
 
 // calls.go init.0 129 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":null}
 // callsite: calls.go:130:16|0 flagstr "CallSiteInInitFunc" flagval 4 score 22 mask 2 maskstr "initFuncAdj"
 // <endcallsites>
 // <endfuncpreamble>
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/funcflags.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/funcflags.go
index 4b9dbc2bb4..f3d74241b4 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/funcflags.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/funcflags.go
@@ -14,7 +14,7 @@ import "os"
 // funcflags.go T_simple 20 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":null,"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_simple() {
@@ -26,7 +26,7 @@ func T_simple() {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_nested(x int) {
@@ -40,7 +40,7 @@ func T_nested(x int) {
 // funcflags.go T_block1 46 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_block1(x int) {
@@ -54,7 +54,7 @@ func T_block1(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_block2(x int) {
@@ -69,7 +69,7 @@ func T_block2(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_switches1(x int) {
@@ -86,7 +86,7 @@ func T_switches1(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_switches1a(x int) {
@@ -100,7 +100,7 @@ func T_switches1a(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_switches2(x int) {
@@ -117,7 +117,7 @@ func T_switches2(x int) {
 
 // funcflags.go T_switches3 123 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_switches3(x interface{}) {
@@ -132,7 +132,7 @@ func T_switches3(x interface{}) {
 // funcflags.go T_switches4 138 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_switches4(x int) {
@@ -151,7 +151,7 @@ func T_switches4(x int) {
 
 // funcflags.go T_recov 157 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_recov(x int) {
@@ -163,7 +163,7 @@ func T_recov(x int) {
 // funcflags.go T_forloops1 169 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_forloops1(x int) {
@@ -174,7 +174,7 @@ func T_forloops1(x int) {
 
 // funcflags.go T_forloops2 180 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_forloops2(x int) {
@@ -189,7 +189,7 @@ func T_forloops2(x int) {
 
 // funcflags.go T_forloops3 195 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_forloops3(x int) {
@@ -209,7 +209,7 @@ func T_forloops3(x int) {
 
 // funcflags.go T_hasgotos 215 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_hasgotos(x int, y int) {
@@ -240,7 +240,7 @@ func T_hasgotos(x int, y int) {
 //   0 ParamMayFeedIfOrSwitch
 //   1 ParamNoInfo
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[64,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[64,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_break_with_label(x int, y int) {
@@ -262,7 +262,7 @@ lab1:
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_callsexit(x int) {
@@ -274,7 +274,7 @@ func T_callsexit(x int) {
 
 // funcflags.go T_exitinexpr 281 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // callsite: funcflags.go:286:18|0 flagstr "CallSiteOnPanicPath" flagval 2 score 102 mask 1 maskstr "panicPathAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -291,7 +291,7 @@ func T_exitinexpr(x int) {
 // funcflags.go T_select_noreturn 297 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[0,0,0],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[0,0,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_select_noreturn(chi chan int, chf chan float32, p *int) {
@@ -327,7 +327,7 @@ func T_select_mayreturn(chi chan int, chf chan float32, p *int) int {
 // funcflags.go T_calls_callsexit 334 0 1
 // Flags FuncPropNeverReturns
 // <endpropsdump>
-// {"Flags":1,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":1,"ParamFlags":[0],"ResultFlags":null}
 // callsite: funcflags.go:335:15|0 flagstr "CallSiteOnPanicPath" flagval 2 score 102 mask 1 maskstr "panicPathAdj"
 // <endcallsites>
 // <endfuncpreamble>
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/params.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/params.go
index 1d58b930e4..1a3073c25c 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/params.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/params.go
@@ -14,7 +14,7 @@ import "os"
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_simple(x int) {
@@ -29,7 +29,7 @@ func T_feeds_if_simple(x int) {
 //   0 ParamMayFeedIfOrSwitch
 //   1 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[64,32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[64,32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_nested(x, y int) {
@@ -45,7 +45,7 @@ func T_feeds_if_nested(x, y int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_pointer(xp *int) {
@@ -60,7 +60,7 @@ func T_feeds_if_pointer(xp *int) {
 //   0 ParamFeedsIfOrSwitch
 //   1 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32,32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32,32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func (r T) T_feeds_if_simple_method(x int) {
@@ -80,7 +80,7 @@ func (r T) T_feeds_if_simple_method(x int) {
 //   2 ParamNoInfo
 //   3 ParamNoInfo
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,32,0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,32,0,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_blanks(_ string, x int, _ bool, _ bool) {
@@ -95,7 +95,7 @@ func T_feeds_if_blanks(_ string, x int, _ bool, _ bool) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_with_copy(x int) {
@@ -109,7 +109,7 @@ func T_feeds_if_with_copy(x int) {
 
 // params.go T_feeds_if_with_copy_expr 115 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_with_copy_expr(x int) {
@@ -125,7 +125,7 @@ func T_feeds_if_with_copy_expr(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_switch(x int) {
@@ -140,7 +140,7 @@ func T_feeds_switch(x int) {
 
 // params.go T_feeds_if_toocomplex 146 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_toocomplex(x int, y int) {
@@ -155,7 +155,7 @@ func T_feeds_if_toocomplex(x int, y int) {
 
 // params.go T_feeds_if_redefined 161 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_redefined(x int) {
@@ -169,7 +169,7 @@ func T_feeds_if_redefined(x int) {
 
 // params.go T_feeds_if_redefined2 175 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_redefined2(x int) {
@@ -190,7 +190,7 @@ func T_feeds_if_redefined2(x int) {
 //   0 ParamFeedsIfOrSwitch
 //   1 ParamNoInfo
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32,0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_multi_if(x int, y int) {
@@ -210,7 +210,7 @@ func T_feeds_multi_if(x int, y int) {
 
 // params.go T_feeds_if_redefined_indirectwrite 216 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_redefined_indirectwrite(x int) {
@@ -225,7 +225,7 @@ func T_feeds_if_redefined_indirectwrite(x int) {
 
 // params.go T_feeds_if_redefined_indirectwrite_copy 231 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_redefined_indirectwrite_copy(x int) {
@@ -245,7 +245,7 @@ func T_feeds_if_redefined_indirectwrite_copy(x int) {
 // ParamFlags
 //   0 ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[32],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[32],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_expr1(x int) {
@@ -256,7 +256,7 @@ func T_feeds_if_expr1(x int) {
 
 // params.go T_feeds_if_expr2 262 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_expr2(x int) {
@@ -267,7 +267,7 @@ func T_feeds_if_expr2(x int) {
 
 // params.go T_feeds_if_expr3 273 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_expr3(x int) {
@@ -293,7 +293,7 @@ func T_feeds_if_shift_may_panic(x int) *int {
 
 // params.go T_feeds_if_maybe_divide_by_zero 299 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_if_maybe_divide_by_zero(x int) {
@@ -307,7 +307,7 @@ func T_feeds_if_maybe_divide_by_zero(x int) {
 // ParamFlags
 //   0 ParamMayFeedIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[16],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[16],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_indcall(x func()) {
@@ -320,7 +320,7 @@ func T_feeds_indcall(x func()) {
 // ParamFlags
 //   0 ParamMayFeedIndirectCall|ParamFeedsIfOrSwitch
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[48],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[48],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_indcall_and_if(x func()) {
@@ -333,7 +333,7 @@ func T_feeds_indcall_and_if(x func()) {
 // ParamFlags
 //   0 ParamFeedsIndirectCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[8],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[8],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_indcall_with_copy(x func()) {
@@ -348,7 +348,7 @@ func T_feeds_indcall_with_copy(x func()) {
 // ParamFlags
 //   0 ParamFeedsInterfaceMethodCall
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[2],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[2],"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_feeds_interface_method_call(i I) {
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/returns.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/returns.go
index ef04516c09..9c68e78cb5 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/returns.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/returns.go
@@ -15,7 +15,7 @@ import "unsafe"
 // ResultFlags
 //   0 ResultIsAllocatedMem
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[2]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[2]}
 // <endcallsites>
 // <endfuncpreamble>
 func T_simple_allocmem() *Bar {
@@ -66,7 +66,7 @@ func T_allocmem_three_returns(x int) []*Bar {
 // ResultFlags
 //   0 ResultAlwaysSameConstant
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[8]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[8]}
 // <endcallsites>
 // <endfuncpreamble>
 func T_return_nil() *Bar {
@@ -247,7 +247,7 @@ func T_return_concrete_type_to_itf_mixed(x, y int) Itf {
 // ResultFlags
 //   0 ResultAlwaysSameInlinableFunc
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[32]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[32]}
 // <endcallsites>
 // <endfuncpreamble>
 func T_return_same_func() func(int) int {
@@ -260,7 +260,7 @@ func T_return_same_func() func(int) int {
 
 // returns.go T_return_different_funcs 266 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[0]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[0]}
 // <endcallsites>
 // <endfuncpreamble>
 func T_return_different_funcs() func(int) int {
@@ -275,7 +275,7 @@ func T_return_different_funcs() func(int) int {
 // ResultFlags
 //   0 ResultAlwaysSameInlinableFunc
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[32]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[32]}
 // <endcallsites>
 // <endfuncpreamble>
 // returns.go T_return_same_closure.func1 287 0 1
@@ -294,7 +294,7 @@ func T_return_same_closure() func(int) int {
 
 // returns.go T_return_different_closures 312 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[0]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":[0]}
 // <endcallsites>
 // <endfuncpreamble>
 // returns.go T_return_different_closures.func1 313 0 1
@@ -332,7 +332,7 @@ func T_return_different_closures() func(int) int {
 // <endfuncpreamble>
 // returns.go T_return_noninlinable.func1.1 340 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":null}
 // <endcallsites>
 // <endfuncpreamble>
 func T_return_noninlinable(x int) func(int) int {
diff --git a/src/cmd/compile/internal/inline/inlheur/testdata/props/returns2.go b/src/cmd/compile/internal/inline/inlheur/testdata/props/returns2.go
index 1bd23e74fa..7200926fb8 100644
--- a/src/cmd/compile/internal/inline/inlheur/testdata/props/returns2.go
+++ b/src/cmd/compile/internal/inline/inlheur/testdata/props/returns2.go
@@ -11,7 +11,7 @@ package returns2
 
 // returns2.go T_return_feeds_iface_call 18 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":null}
 // callsite: returns2.go:19:13|0 flagstr "" flagval 0 score 1 mask 16384 maskstr "returnFeedsConcreteToInterfaceCallAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -22,7 +22,7 @@ func T_return_feeds_iface_call() {
 
 // returns2.go T_multi_return_feeds_iface_call 29 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":null,"ResultFlags":null}
 // callsite: returns2.go:30:20|0 flagstr "" flagval 0 score 3 mask 16384 maskstr "returnFeedsConcreteToInterfaceCallAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -33,7 +33,7 @@ func T_multi_return_feeds_iface_call() {
 
 // returns2.go T_returned_inlinable_func_feeds_indirect_call 41 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // callsite: returns2.go:42:18|0 flagstr "" flagval 0 score -51 mask 8200 maskstr "passConstToIfAdj|returnFeedsInlinableFuncToIndCallAdj"
 // callsite: returns2.go:44:20|1 flagstr "" flagval 0 score -23 mask 8192 maskstr "returnFeedsInlinableFuncToIndCallAdj"
 // <endcallsites>
@@ -47,7 +47,7 @@ func T_returned_inlinable_func_feeds_indirect_call(q int) {
 
 // returns2.go T_returned_noninlineable_func_feeds_indirect_call 54 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // callsite: returns2.go:55:30|0 flagstr "" flagval 0 score -23 mask 4096 maskstr "returnFeedsFuncToIndCallAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -58,7 +58,7 @@ func T_returned_noninlineable_func_feeds_indirect_call(q int) {
 
 // returns2.go T_multi_return_feeds_indirect_call 65 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0],"ResultFlags":null}
 // callsite: returns2.go:66:29|0 flagstr "" flagval 0 score -21 mask 8192 maskstr "returnFeedsInlinableFuncToIndCallAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -125,7 +125,7 @@ func T_two_calls_feed_ifswitch(q int) int {
 
 // returns2.go T_chained_indirect_call 132 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // callsite: returns2.go:135:18|0 flagstr "" flagval 0 score -31 mask 8192 maskstr "returnFeedsInlinableFuncToIndCallAdj"
 // <endcallsites>
 // <endfuncpreamble>
@@ -137,7 +137,7 @@ func T_chained_indirect_call(x, y int) {
 
 // returns2.go T_chained_conc_iface_call 144 0 1
 // <endpropsdump>
-// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":[]}
+// {"Flags":0,"ParamFlags":[0,0],"ResultFlags":null}
 // callsite: returns2.go:148:8|0 flagstr "" flagval 0 score 1 mask 16384 maskstr "returnFeedsConcreteToInterfaceCallAdj"
 // <endcallsites>
 // <endfuncpreamble>